[PATCH 0/5] The Beaglebone capemanager

[PATCH 0/5] The Beaglebone capemanager

[Pantelis Antoniou]

This patchset introduces the beaglebone capemanager.
It allows seamless support for plugin boards for the beaglebone
family of boards via means of automatically loaded device tree
overlays.

For the EEPROM access it performs it is dependent on
Srinivas Kandagatla's EEPROM framework as posted in
https://lkml.org/lkml/2015/3/30/731.

The patch that adds the EEPROM framework interface to the at24
driver has been posted today and the subject line is:
"i2c: eeprom: at24: Provide an EEPROM framework interface"

The first patch contains the driver itself, while the rest
are just documentation entries and MAINTAINERS file updates.

Pantelis Antoniou (5):
  misc: Beaglebone capemanager
  doc: misc: Beaglebone capemanager documentation
  doc: dt: beaglebone cape manager bindings.
  doc: ABI: bone_capemgr sysfs API
  MAINTAINERS: Beaglebone capemanager maintainer

 .../testing/sysfs-devices-platform-bone_capemgr    |   63 +
 .../devicetree/bindings/misc/bone_capemgr.txt      |  123 ++
 Documentation/misc-devices/bone_capemgr.txt        |   63 +
 MAINTAINERS                                        |    8 +
 drivers/misc/Kconfig                               |   10 +
 drivers/misc/Makefile                              |    1 +
 drivers/misc/bone_capemgr.c                        | 1926 ++++++++++++++++++++
 7 files changed, 2194 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
 create mode 100644 Documentation/devicetree/bindings/misc/bone_capemgr.txt
 create mode 100644 Documentation/misc-devices/bone_capemgr.txt
 create mode 100644 drivers/misc/bone_capemgr.c

-- 
1.7.12

[PATCH 1/5] misc: Beaglebone capemanager

[Pantelis Antoniou]

A cape loader based on DT overlays and DT objects.

This is the beaglebone cape manager which allows capes to be automatically
probed and instantiated via means of a device tree overlay deduced from
the part-number and version contained on the cape's EEPROM.

The reference manual contains information about the specification
and the contents of the EEPROM.

http://beagleboard.org/static/beaglebone/latest/Docs/Hardware/BONE_SRM.pdf

Documentation about the workings of the cape manager is located
in Documentation/misc-devices/bone_capemgr.txt

This driver is using the EEPROM framework interface to retrieve
the data stored on the baseboard and cape EEPROMs.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
---
 drivers/misc/Kconfig        |   10 +
 drivers/misc/Makefile       |    1 +
 drivers/misc/bone_capemgr.c | 1926 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1937 insertions(+)
 create mode 100644 drivers/misc/bone_capemgr.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 006242c..f9e09e1 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -515,6 +515,16 @@ config VEXPRESS_SYSCFG
 	  bus. System Configuration interface is one of the possible means
 	  of generating transactions on this bus.
 
+config BONE_CAPEMGR
+	tristate "Beaglebone cape manager"
+	depends on ARCH_OMAP2PLUS && OF
+	select EEPROM
+	select OF_OVERLAY
+	default n
+	help
+	  Say Y here to include support for automatic loading of
+	  beaglebone capes.
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 7d5c4cd..659b78b 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -56,3 +56,4 @@ obj-$(CONFIG_GENWQE)		+= genwqe/
 obj-$(CONFIG_ECHO)		+= echo/
 obj-$(CONFIG_VEXPRESS_SYSCFG)	+= vexpress-syscfg.o
 obj-$(CONFIG_CXL_BASE)		+= cxl/
+obj-$(CONFIG_BONE_CAPEMGR)	+= bone_capemgr.o
diff --git a/drivers/misc/bone_capemgr.c b/drivers/misc/bone_capemgr.c
new file mode 100644
index 0000000..423719c
--- /dev/null
+++ b/drivers/misc/bone_capemgr.c
@@ -0,0 +1,1926 @@
+/*
+ * TI Beaglebone cape manager
+ *
+ * Copyright (C) 2012 Texas Instruments Inc.
+ * Copyright (C) 2012-2015 Konsulko Group.
+ * Author: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/completion.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_fdt.h>
+#include <linux/slab.h>
+#include <linux/pm_runtime.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/firmware.h>
+#include <linux/err.h>
+#include <linux/ctype.h>
+#include <linux/string.h>
+#include <linux/memory.h>
+#include <linux/kthread.h>
+#include <linux/wait.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/eeprom-consumer.h>
+
+/* disabled capes */
+static char *disable_partno;
+module_param(disable_partno, charp, 0444);
+MODULE_PARM_DESC(disable_partno,
+		"Comma delimited list of PART-NUMBER[:REV] of disabled capes");
+
+/* enable capes */
+static char *enable_partno;
+module_param(enable_partno, charp, 0444);
+MODULE_PARM_DESC(enable_partno,
+		"Comma delimited list of PART-NUMBER[:REV] of enabled capes");
+
+/* delay to scan on boot until rootfs appears */
+static int boot_scan_period = 1000;
+module_param(boot_scan_period, int, 0444);
+MODULE_PARM_DESC(boot_scan_period,
+		"boot scan period until rootfs firmware is available");
+
+struct capemgr_info;
+
+struct slot_ee_attribute {
+	struct device_attribute devattr;
+	unsigned int field;
+	struct bone_cape_slot *slot;	/* this is filled when instantiated */
+};
+#define to_slot_ee_attribute(x) \
+	container_of((x), struct slot_ee_attribute, devattr)
+
+struct bbrd_ee_attribute {
+	struct device_attribute devattr;
+	unsigned int field;
+};
+#define to_bbrd_ee_attribute(x) \
+	container_of((x), struct bbrd_ee_attribute, devattr)
+
+struct bone_cape_slot {
+	struct list_head	node;
+	struct capemgr_info	*info;
+	int			slotno;
+	u32			eeprom_handle;
+	int			eeprom_addr;
+	struct eeprom_cell	*eeprom_cell;
+
+	char			text_id[256];
+	char			signature[256];
+	/* quick access */
+	char			board_name[32+1];
+	char			version[4+1];
+	char			manufacturer[16+1];
+	char			part_number[16+1];
+
+	/* attribute group */
+	char			*ee_attr_name;
+	int			ee_attrs_count;
+	struct slot_ee_attribute *ee_attrs;
+	struct attribute	**ee_attrs_tab;
+	struct attribute_group	attrgroup;
+
+	/* state flags */
+	unsigned int		probed : 1;
+	unsigned int		probe_failed : 1;
+	unsigned int		override : 1;
+	unsigned int		loading : 1;
+	unsigned int		loaded : 1;
+	unsigned int		retry_loading : 1;
+	unsigned int		disabled : 1;
+
+	char			*dtbo;
+	const struct firmware	*fw;
+	struct device_node	*overlay;
+	int			overlay_id;
+
+	/* loader thread */
+	struct task_struct	*loader_thread;
+
+	/* load priority */
+	int priority;
+};
+
+struct bone_baseboard {
+
+	/* from the matched boardmap node */
+	char			*compatible_name;
+
+	/* filled in by reading the eeprom */
+	char			signature[256];
+	char			text_id[64+1];
+
+	/* quick access */
+	char			board_name[8+1];
+	char			revision[4+1];
+	char			serial_number[12+1];
+
+	/* access to the eeprom */
+	u32			eeprom_handle;
+	int			eeprom_addr;
+	struct eeprom_cell	*eeprom_cell;
+};
+
+struct capemgr_info {
+	struct platform_device	*pdev;
+
+	atomic_t next_slot_nr;
+	struct list_head	slot_list;
+	struct mutex		slots_list_mutex;
+
+	/* baseboard EEPROM data */
+	struct bone_baseboard	baseboard;
+
+	/* wait queue for keeping the priorities straight */
+	wait_queue_head_t	load_wq;
+};
+
+static int bone_slot_fill_override(struct bone_cape_slot *slot,
+		struct device_node *node,
+		const char *part_number, const char *version);
+static struct bone_cape_slot *capemgr_add_slot(
+		struct capemgr_info *info, struct device_node *node,
+		const char *part_number, const char *version, int prio);
+static int capemgr_remove_slot_no_lock(struct bone_cape_slot *slot);
+static int capemgr_remove_slot(struct bone_cape_slot *slot);
+static int capemgr_load_slot(struct bone_cape_slot *slot);
+static int capemgr_unload_slot(struct bone_cape_slot *slot);
+
+/* baseboard EEPROM field definition */
+#define BBRD_EE_FIELD_HEADER		0
+#define BBRD_EE_FIELD_BOARD_NAME	1
+#define BBRD_EE_FIELD_REVISION		2
+#define BBRD_EE_FIELD_SERIAL_NUMBER	3
+#define BBRD_EE_FIELD_CONFIG_OPTION	4
+#define BBRD_EE_FILED_RSVD1		5
+#define BBRD_EE_FILED_RSVD2		6
+#define BBRD_EE_FILED_RSVD3		7
+
+/* cape EEPROM field definitions */
+#define CAPE_EE_FIELD_HEADER		0
+#define CAPE_EE_FIELD_EEPROM_REV	1
+#define CAPE_EE_FIELD_BOARD_NAME	2
+#define CAPE_EE_FIELD_VERSION		3
+#define CAPE_EE_FIELD_MANUFACTURER	4
+#define CAPE_EE_FIELD_PART_NUMBER	5
+#define CAPE_EE_FIELD_NUMBER_OF_PINS	6
+#define CAPE_EE_FIELD_SERIAL_NUMBER	7
+#define CAPE_EE_FIELD_PIN_USAGE		8
+#define CAPE_EE_FIELD_VDD_3V3EXP	9
+#define CAPE_EE_FIELD_VDD_5V		10
+#define CAPE_EE_FIELD_SYS_5V		11
+#define CAPE_EE_FIELD_DC_SUPPLIED	12
+#define CAPE_EE_FIELD_FIELDS_NR		13
+
+#define EE_FIELD_MAKE_HEADER(p)	\
+	({ \
+		const u8 *_p = (p); \
+		(((u32)_p[0] << 24) | ((u32)_p[1] << 16) | \
+		 ((u32)_p[2] <<  8) |  (u32)_p[3]); \
+	})
+
+#define EE_FIELD_HEADER_VALID	0xaa5533ee
+
+struct ee_field {
+	const char	*name;
+	int		start;
+	int		size;
+	unsigned int	ascii : 1;
+	unsigned int	strip_trailing_dots : 1;
+	const char	*override;
+};
+
+/* baseboard EEPROM definitions */
+static const struct ee_field bbrd_sig_fields[] = {
+	[BBRD_EE_FIELD_HEADER] = {
+		.name		= "header",
+		.start		= 0,
+		.size		= 4,
+		.ascii		= 0,
+		.override	= "\xaa\x55\x33\xee",	/* AA 55 33 EE */
+	},
+	[BBRD_EE_FIELD_BOARD_NAME] = {
+		.name		= "board-name",
+		.start		= 4,
+		.size		= 8,
+		.ascii		= 1,
+		.strip_trailing_dots = 1,
+		.override	= "Board Name",
+	},
+	[BBRD_EE_FIELD_REVISION] = {
+		.name		= "revision",
+		.start		= 12,
+		.size		= 4,
+		.ascii		= 1,
+		.override	= "00A0",
+	},
+	[BBRD_EE_FIELD_SERIAL_NUMBER] = {
+		.name		= "serial-number",
+		.start		= 16,
+		.size		= 12,
+		.ascii		= 1,
+		.override	= "0000000000",
+	},
+	[BBRD_EE_FIELD_CONFIG_OPTION] = {
+		.name		= "config-option",
+		.start		= 28,
+		.size		= 32,
+	},
+};
+
+/* cape EEPROM definitions */
+static const struct ee_field cape_sig_fields[] = {
+	[CAPE_EE_FIELD_HEADER] = {
+		.name		= "header",
+		.start		= 0,
+		.size		= 4,
+		.ascii		= 0,
+		.override	= "\xaa\x55\x33\xee",	/* AA 55 33 EE */
+	},
+	[CAPE_EE_FIELD_EEPROM_REV] = {
+		.name		= "eeprom-format-revision",
+		.start		= 4,
+		.size		= 2,
+		.ascii		= 1,
+		.override	= "A0",
+	},
+	[CAPE_EE_FIELD_BOARD_NAME] = {
+		.name		= "board-name",
+		.start		= 6,
+		.size		= 32,
+		.ascii		= 1,
+		.strip_trailing_dots = 1,
+		.override	= "Override Board Name",
+	},
+	[CAPE_EE_FIELD_VERSION] = {
+		.name		= "version",
+		.start		= 38,
+		.size		= 4,
+		.ascii		= 1,
+		.override	= "00A0",
+	},
+	[CAPE_EE_FIELD_MANUFACTURER] = {
+		.name		= "manufacturer",
+		.start		= 42,
+		.size		= 16,
+		.ascii		= 1,
+		.strip_trailing_dots = 1,
+		.override	= "Override Manuf",
+	},
+	[CAPE_EE_FIELD_PART_NUMBER] = {
+		.name		= "part-number",
+		.start		= 58,
+		.size		= 16,
+		.ascii		= 1,
+		.strip_trailing_dots = 1,
+		.override	= "Override Part#",
+	},
+	[CAPE_EE_FIELD_NUMBER_OF_PINS] = {
+		.name		= "number-of-pins",
+		.start		= 74,
+		.size		= 2,
+		.ascii		= 0,
+		.override	= NULL,
+	},
+	[CAPE_EE_FIELD_SERIAL_NUMBER] = {
+		.name		= "serial-number",
+		.start		= 76,
+		.size		= 12,
+		.ascii		= 1,
+		.override	= "0000000000",
+	},
+	[CAPE_EE_FIELD_PIN_USAGE] = {
+		.name		= "pin-usage",
+		.start		= 88,
+		.size		= 140,
+		.ascii		= 0,
+		.override	= NULL,
+	},
+	[CAPE_EE_FIELD_VDD_3V3EXP] = {
+		.name		= "vdd-3v3exp",
+		.start		= 228,
+		.size		= 2,
+		.ascii		= 0,
+		.override	= NULL,
+	},
+	[CAPE_EE_FIELD_VDD_5V] = {
+		.name		= "vdd-5v",
+		.start		= 230,
+		.size		= 2,
+		.ascii		= 0,
+		.override	= NULL,
+	},
+	[CAPE_EE_FIELD_SYS_5V] = {
+		.name		= "sys-5v",
+		.start		= 232,
+		.size		= 2,
+		.ascii		= 0,
+		.override	= NULL,
+	},
+	[CAPE_EE_FIELD_DC_SUPPLIED] = {
+		.name		= "dc-supplied",
+		.start		= 234,
+		.size		= 2,
+		.ascii		= 0,
+		.override	= NULL,
+	},
+};
+
+static char *ee_field_get(const struct ee_field *sig_field,
+		const void *data, int field, char *buf, int bufsz)
+{
+	int len;
+
+	/* enough space? */
+	if (bufsz < sig_field->size + sig_field->ascii)
+		return NULL;
+
+	memcpy(buf, (char *)data + sig_field->start, sig_field->size);
+
+	/* terminate ascii field */
+	if (sig_field->ascii)
+		buf[sig_field->size] = '\0';
+
+	if (sig_field->strip_trailing_dots) {
+		len = strlen(buf);
+		while (len > 1 && buf[len - 1] == '.')
+			buf[--len] = '\0';
+	}
+
+	return buf;
+}
+
+char *bbrd_ee_field_get(const void *data,
+		int field, char *buf, int bufsz)
+{
+	if ((unsigned int)field >= ARRAY_SIZE(bbrd_sig_fields))
+		return NULL;
+
+	return ee_field_get(&bbrd_sig_fields[field], data, field, buf, bufsz);
+}
+
+char *cape_ee_field_get(const void *data,
+		int field, char *buf, int bufsz)
+{
+	if ((unsigned int)field >= ARRAY_SIZE(cape_sig_fields))
+		return NULL;
+
+	return ee_field_get(&cape_sig_fields[field], data, field, buf, bufsz);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id capemgr_of_match[] = {
+	{
+		.compatible = "ti,bone-capemgr",
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, capemgr_of_match);
+
+#endif
+
+static int bone_baseboard_scan(struct bone_baseboard *bbrd)
+{
+	struct capemgr_info *info = container_of(bbrd,
+			struct capemgr_info, baseboard);
+	const u8 *p;
+	int ret;
+	size_t len;
+
+	p = eeprom_cell_read(bbrd->eeprom_cell, &len);
+	if (IS_ERR(p)) {
+		ret = PTR_ERR(p);
+		dev_err(&info->pdev->dev,
+			"Cannot read cell (ret=%d)\n", ret);
+		return ret;
+	}
+	if (len < sizeof(bbrd->signature)) {
+		dev_info(&info->pdev->dev,
+			"Short read %d (should be >= %d bytes)\n",
+			len, sizeof(bbrd->signature));
+		return -EINVAL;
+	}
+	memcpy(bbrd->signature, p, sizeof(bbrd->signature));
+
+	p = bbrd->signature;
+	if (EE_FIELD_MAKE_HEADER(p) != EE_FIELD_HEADER_VALID) {
+		dev_err(&info->pdev->dev, "Invalid board signature '%08x'\n",
+			EE_FIELD_MAKE_HEADER(p));
+		return -ENODEV;
+	}
+
+	bbrd_ee_field_get(bbrd->signature,
+			BBRD_EE_FIELD_BOARD_NAME,
+			bbrd->board_name, sizeof(bbrd->board_name));
+	bbrd_ee_field_get(bbrd->signature,
+			BBRD_EE_FIELD_REVISION,
+			bbrd->revision, sizeof(bbrd->revision));
+	bbrd_ee_field_get(bbrd->signature,
+			BBRD_EE_FIELD_SERIAL_NUMBER,
+			bbrd->serial_number, sizeof(bbrd->serial_number));
+
+	/* board_name,version,manufacturer,part_number */
+	snprintf(bbrd->text_id, sizeof(bbrd->text_id) - 1,
+			"%s,%s,%s", bbrd->board_name, bbrd->revision,
+			bbrd->serial_number);
+
+	/* terminate always */
+	bbrd->text_id[sizeof(bbrd->text_id) - 1] = '\0';
+
+	return 0;
+}
+
+static int bone_slot_scan(struct bone_cape_slot *slot)
+{
+	struct capemgr_info *info = slot->info;
+	const u8 *p;
+	int r;
+	ssize_t len;
+
+	/* need to read EEPROM? */
+	if (slot->probed)
+		goto slot_fail_check;
+
+	slot->probed = 1;
+
+	if (!slot->override) {
+
+		p = eeprom_cell_read(slot->eeprom_cell, &len);
+		if (IS_ERR(p)) {
+			r = PTR_ERR(p);
+			slot->probe_failed = 1;
+
+			/* timeout is normal when no cape is present */
+			if (r != -ETIMEDOUT)
+				dev_err(&info->pdev->dev,
+					"Cannot read cell (ret=%d)\n", r);
+			return r;
+		}
+		if (len < sizeof(slot->signature)) {
+			dev_info(&info->pdev->dev,
+				"Short read %d (should be >= %d bytes)\n",
+				len, sizeof(slot->signature));
+			return -EINVAL;
+		}
+		memcpy(slot->signature, p, sizeof(slot->signature));
+
+	} else
+		dev_info(&info->pdev->dev,
+			"Using override eeprom data at slot %d\n",
+			slot->slotno);
+
+	p = slot->signature;
+	if (EE_FIELD_MAKE_HEADER(p) != EE_FIELD_HEADER_VALID) {
+		dev_err(&info->pdev->dev,
+			"Invalid signature '%08x' at slot %d\n",
+			EE_FIELD_MAKE_HEADER(p), slot->slotno);
+		slot->probe_failed = 1;
+		return -ENODEV;
+	}
+
+	cape_ee_field_get(slot->signature,
+			CAPE_EE_FIELD_BOARD_NAME,
+			slot->board_name, sizeof(slot->board_name));
+	cape_ee_field_get(slot->signature,
+			CAPE_EE_FIELD_VERSION,
+			slot->version, sizeof(slot->version));
+	cape_ee_field_get(slot->signature,
+			CAPE_EE_FIELD_MANUFACTURER,
+			slot->manufacturer, sizeof(slot->manufacturer));
+	cape_ee_field_get(slot->signature,
+			CAPE_EE_FIELD_PART_NUMBER,
+			slot->part_number, sizeof(slot->part_number));
+
+	/* board_name,version,manufacturer,part_number */
+	snprintf(slot->text_id, sizeof(slot->text_id) - 1,
+			"%s,%s,%s,%s", slot->board_name, slot->version,
+			slot->manufacturer, slot->part_number);
+
+	/* terminate always */
+	slot->text_id[sizeof(slot->text_id) - 1] = '\0';
+
+slot_fail_check:
+	/* slot has failed and we don't support hotpluging */
+	if (slot->probe_failed)
+		return -ENODEV;
+
+	return 0;
+}
+
+/* return 0 if not matched,, 1 if matched */
+static int bone_match_cape(const char *match,
+		const char *part_number, const char *version)
+{
+	char *tmp_part_number, *tmp_version;
+	char *buf, *s, *e, *sn;
+	int found;
+
+	if (match == NULL || part_number == NULL)
+		return 0;
+
+	/* copy the argument to work on it */
+	buf = kstrdup(match, GFP_KERNEL);
+
+	/* no memory, too bad... */
+	if (buf == NULL)
+		return 0;
+
+	found = 0;
+	s = buf;
+	e = s + strlen(s);
+	while (s < e) {
+		/* find comma separator */
+		sn = strchr(s, ',');
+		if (sn != NULL)
+			*sn++ = '\0';
+		else
+			sn = e;
+		tmp_part_number = s;
+		tmp_version = strchr(tmp_part_number, ':');
+		if (tmp_version != NULL)
+			*tmp_version++ = '\0';
+		s = sn;
+
+		/* the part names must match */
+		if (strcmp(tmp_part_number, part_number) != 0)
+			continue;
+
+		/* if there's no version, match any */
+		if (version == NULL || tmp_version == NULL ||
+			strcmp(version, tmp_version) == 0) {
+			found = 1;
+			break;
+		}
+	}
+
+	kfree(buf);
+
+	return found;
+}
+
+/* helper method */
+static int of_multi_prop_cmp(const struct property *prop, const char *value)
+{
+	const char *cp;
+	int cplen, vlen, l;
+
+	/* check if it's directly compatible */
+	cp = prop->value;
+	cplen = prop->length;
+	vlen = strlen(value);
+
+	while (cplen > 0) {
+		/* compatible? */
+		if (of_compat_cmp(cp, value, vlen) == 0)
+			return 0;
+		l = strlen(cp) + 1;
+		cp += l;
+		cplen -= l;
+	}
+	return -1;
+}
+
+static ssize_t slot_ee_attr_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct slot_ee_attribute *ee_attr = to_slot_ee_attribute(attr);
+	struct bone_cape_slot *slot = ee_attr->slot;
+	const struct ee_field *sig_field;
+	int i, len;
+	char *p, *s;
+	u16 val;
+
+	/* add newline for ascii fields */
+	sig_field = &cape_sig_fields[ee_attr->field];
+
+	len = sig_field->size + sig_field->ascii;
+	p = kmalloc(len, GFP_KERNEL);
+	if (p == NULL)
+		return -ENOMEM;
+
+	s = cape_ee_field_get(slot->signature, ee_attr->field, p, len);
+	if (s == NULL)
+		return -EINVAL;
+
+	/* add newline for ascii fields and return */
+	if (sig_field->ascii) {
+		len = sprintf(buf, "%s\n", s);
+		goto out;
+	}
+
+	/* case by case handling */
+	switch (ee_attr->field) {
+	case CAPE_EE_FIELD_HEADER:
+		len = sprintf(buf, "%02x %02x %02x %02x\n",
+				s[0], s[1], s[2], s[3]);
+		break;
+
+		/* 2 bytes */
+	case CAPE_EE_FIELD_NUMBER_OF_PINS:
+	case CAPE_EE_FIELD_VDD_3V3EXP:
+	case CAPE_EE_FIELD_VDD_5V:
+	case CAPE_EE_FIELD_SYS_5V:
+	case CAPE_EE_FIELD_DC_SUPPLIED:
+		/* the bone is LE */
+		val = s[0] & (s[1] << 8);
+		len = sprintf(buf, "%u\n", (unsigned int)val & 0xffff);
+		break;
+
+	case CAPE_EE_FIELD_PIN_USAGE:
+
+		len = 0;
+		for (i = 0; i < sig_field->size / 2; i++) {
+			/* the bone is LE */
+			val = s[0] & (s[1] << 8);
+			sprintf(buf, "%04x\n", val);
+			buf += 5;
+			len += 5;
+			s += 2;
+		}
+
+		break;
+
+	default:
+		*buf = '\0';
+		len = 0;
+		break;
+	}
+
+out:
+	kfree(p);
+
+	return len;
+}
+
+#define SLOT_EE_ATTR(_name, _field) \
+	{ \
+		.devattr = __ATTR(_name, S_IRUGO, slot_ee_attr_show, NULL), \
+		.field = CAPE_EE_FIELD_##_field, \
+		.slot = NULL, \
+	}
+
+static const struct slot_ee_attribute slot_ee_attrs[] = {
+	SLOT_EE_ATTR(header, HEADER),
+	SLOT_EE_ATTR(eeprom-format-revision, EEPROM_REV),
+	SLOT_EE_ATTR(board-name, BOARD_NAME),
+	SLOT_EE_ATTR(version, VERSION),
+	SLOT_EE_ATTR(manufacturer, MANUFACTURER),
+	SLOT_EE_ATTR(part-number, PART_NUMBER),
+	SLOT_EE_ATTR(number-of-pins, NUMBER_OF_PINS),
+	SLOT_EE_ATTR(serial-number, SERIAL_NUMBER),
+	SLOT_EE_ATTR(pin-usage, PIN_USAGE),
+	SLOT_EE_ATTR(vdd-3v3exp, VDD_3V3EXP),
+	SLOT_EE_ATTR(vdd-5v, VDD_5V),
+	SLOT_EE_ATTR(sys-5v, SYS_5V),
+	SLOT_EE_ATTR(dc-supplied, DC_SUPPLIED),
+};
+
+static int bone_cape_slot_sysfs_register(struct bone_cape_slot *slot)
+{
+	struct capemgr_info *info = slot->info;
+	struct device *dev = &info->pdev->dev;
+	struct slot_ee_attribute *ee_attr;
+	struct attribute_group *attrgroup;
+	int i, err, sz;
+
+	slot->ee_attr_name = kasprintf(GFP_KERNEL, "slot-%d", slot->slotno);
+	if (slot->ee_attr_name == NULL) {
+		dev_err(dev, "slot #%d: Failed to allocate ee_attr_name\n",
+				slot->slotno);
+		err = -ENOMEM;
+		goto err_fail_no_ee_attr_name;
+	}
+
+	slot->ee_attrs_count = ARRAY_SIZE(slot_ee_attrs);
+
+	sz = slot->ee_attrs_count * sizeof(*slot->ee_attrs);
+	slot->ee_attrs = kmalloc(sz, GFP_KERNEL);
+	if (slot->ee_attrs == NULL) {
+		dev_err(dev, "slot #%d: Failed to allocate ee_attrs\n",
+				slot->slotno);
+		err = -ENOMEM;
+		goto err_fail_no_ee_attrs;
+	}
+
+	attrgroup = &slot->attrgroup;
+	memset(attrgroup, 0, sizeof(*attrgroup));
+	attrgroup->name = slot->ee_attr_name;
+
+	sz = sizeof(*slot->ee_attrs_tab) * (slot->ee_attrs_count + 1);
+	attrgroup->attrs = kmalloc(sz, GFP_KERNEL);
+	if (attrgroup->attrs == NULL) {
+		dev_err(dev, "slot #%d: Failed to allocate ee_attrs_tab\n",
+				slot->slotno);
+		err = -ENOMEM;
+		goto err_fail_no_ee_attrs_tab;
+	}
+	/* copy everything over */
+	memcpy(slot->ee_attrs, slot_ee_attrs, sizeof(slot_ee_attrs));
+
+	/* bind this attr to the slot */
+	for (i = 0; i < slot->ee_attrs_count; i++) {
+		ee_attr = &slot->ee_attrs[i];
+		ee_attr->slot = slot;
+		attrgroup->attrs[i] = &ee_attr->devattr.attr;
+	}
+	attrgroup->attrs[i] = NULL;
+
+	/* make lockdep happy */
+	for (i = 0; i < slot->ee_attrs_count; i++) {
+		ee_attr = &slot->ee_attrs[i];
+		sysfs_attr_init(&ee_attr->devattr.attr);
+	}
+
+	err = sysfs_create_group(&dev->kobj, attrgroup);
+	if (err != 0) {
+		dev_err(dev, "slot #%d: Failed to allocate ee_attrs_tab\n",
+				slot->slotno);
+		err = -ENOMEM;
+		goto err_fail_no_ee_attrs_group;
+	}
+
+	return 0;
+
+err_fail_no_ee_attrs_group:
+	kfree(slot->ee_attrs_tab);
+err_fail_no_ee_attrs_tab:
+	kfree(slot->ee_attrs);
+err_fail_no_ee_attrs:
+	kfree(slot->ee_attr_name);
+err_fail_no_ee_attr_name:
+	return err;
+}
+
+static void bone_cape_slot_sysfs_unregister(struct bone_cape_slot *slot)
+{
+	struct capemgr_info *info = slot->info;
+	struct device *dev = &info->pdev->dev;
+
+	sysfs_remove_group(&dev->kobj, &slot->attrgroup);
+	kfree(slot->ee_attrs_tab);
+	kfree(slot->ee_attrs);
+	kfree(slot->ee_attr_name);
+}
+
+static ssize_t bbrd_ee_attr_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct bbrd_ee_attribute *ee_attr = to_bbrd_ee_attribute(attr);
+	struct platform_device *pdev = to_platform_device(dev);
+	struct capemgr_info *info = platform_get_drvdata(pdev);
+	struct bone_baseboard *bbrd = &info->baseboard;
+	const struct ee_field *sig_field;
+	u16 val;
+	int i, len;
+	char *p, *s;
+
+	/* add newline for ascii fields */
+	sig_field = &bbrd_sig_fields[ee_attr->field];
+
+	len = sig_field->size + sig_field->ascii;
+	p = kmalloc(len, GFP_KERNEL);
+	if (p == NULL)
+		return -ENOMEM;
+
+	s = bbrd_ee_field_get(bbrd->signature, ee_attr->field, p, len);
+	if (s == NULL)
+		return -EINVAL;
+
+	/* add newline for ascii fields and return */
+	if (sig_field->ascii) {
+		len = sprintf(buf, "%s\n", s);
+		goto out;
+	}
+
+	/* case by case handling */
+	switch (ee_attr->field) {
+	case BBRD_EE_FIELD_HEADER:
+		len = sprintf(buf, "%02x %02x %02x %02x\n",
+				s[0], s[1], s[2], s[3]);
+		break;
+
+	case BBRD_EE_FIELD_CONFIG_OPTION:
+		len = 0;
+		for (i = 0; i < sig_field->size / 2; i++) {
+			/* the bone is LE */
+			val = s[0] & (s[1] << 8);
+			sprintf(buf, "%04x\n", val);
+			buf += 5;
+			len += 5;
+			s += 2;
+		}
+		break;
+
+	default:
+		*buf = '\0';
+		len = 0;
+		break;
+	}
+
+out:
+	kfree(p);
+
+	return len;
+}
+
+#define BBRD_EE_ATTR(_name, _field) \
+	{ \
+		.devattr = __ATTR(_name, 0440, bbrd_ee_attr_show, NULL), \
+		.field = BBRD_EE_FIELD_##_field, \
+	}
+
+static struct bbrd_ee_attribute bbrd_ee_attrs[] = {
+	BBRD_EE_ATTR(header, HEADER),
+	BBRD_EE_ATTR(board-name, BOARD_NAME),
+	BBRD_EE_ATTR(revision, REVISION),
+	BBRD_EE_ATTR(serial-number, SERIAL_NUMBER),
+	BBRD_EE_ATTR(config-option, CONFIG_OPTION),
+};
+
+static struct attribute *bbrd_attrs_flat[] = {
+	&bbrd_ee_attrs[BBRD_EE_FIELD_HEADER].devattr.attr,
+	&bbrd_ee_attrs[BBRD_EE_FIELD_BOARD_NAME].devattr.attr,
+	&bbrd_ee_attrs[BBRD_EE_FIELD_REVISION].devattr.attr,
+	&bbrd_ee_attrs[BBRD_EE_FIELD_SERIAL_NUMBER].devattr.attr,
+	&bbrd_ee_attrs[BBRD_EE_FIELD_CONFIG_OPTION].devattr.attr,
+	NULL,
+};
+
+static const struct attribute_group bbrd_attr_group = {
+	.name	= "baseboard",
+	.attrs	= bbrd_attrs_flat,
+};
+
+static ssize_t slots_show(struct device *dev, struct device_attribute *attr,
+		char *buf);
+static ssize_t slots_store(struct device *dev, struct device_attribute *attr,
+		 const char *buf, size_t count);
+
+static DEVICE_ATTR(slots, 0644, slots_show, slots_store);
+
+static struct attribute *root_attrs_flat[] = {
+	&dev_attr_slots.attr,
+	NULL,
+};
+
+static const struct attribute_group root_attr_group = {
+	.attrs = root_attrs_flat,
+};
+
+static const struct attribute_group *attr_groups[] = {
+	&root_attr_group,
+	&bbrd_attr_group,
+	NULL,
+};
+
+static ssize_t slots_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct capemgr_info *info = platform_get_drvdata(pdev);
+	struct bone_cape_slot *slot;
+	ssize_t len, sz;
+
+	mutex_lock(&info->slots_list_mutex);
+	sz = 0;
+	list_for_each_entry(slot, &info->slot_list, node) {
+
+		len = sprintf(buf, "%2d: %c%c%c%c%c%c %3d %s\n",
+				slot->slotno,
+				slot->probed       ? 'P' : '-',
+				slot->probe_failed ? 'F' : '-',
+				slot->override     ? 'O' : '-',
+				slot->loading	   ? 'l' : '-',
+				slot->loaded	   ? 'L' : '-',
+				slot->disabled     ? 'D' : '-',
+				slot->overlay_id, slot->text_id);
+
+		buf += len;
+		sz += len;
+	}
+	mutex_unlock(&info->slots_list_mutex);
+
+	return sz;
+}
+
+static ssize_t slots_store(struct device *dev, struct device_attribute *attr,
+		 const char *buf, size_t count)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct capemgr_info *info = platform_get_drvdata(pdev);
+	struct bone_cape_slot *slot;
+	struct device_node *pnode, *node, *slots_node;
+	char *s, *part_number, *version;
+	int ret;
+	int slotno;
+
+	/* check for remove slot */
+	if (strlen(buf) > 0 && buf[0] == '-') {
+		ret = kstrtoint(buf + 1, 10, &slotno);
+		if (ret != 0)
+			return ret;
+
+		/* now load each (take lock to be sure */
+		mutex_lock(&info->slots_list_mutex);
+		list_for_each_entry(slot, &info->slot_list, node) {
+			if (slotno == slot->slotno)
+				goto found;
+		}
+
+		mutex_unlock(&info->slots_list_mutex);
+		return -ENODEV;
+found:
+		/* the hardware slots just get unloaded */
+		if (!slot->override) {
+			ret = capemgr_unload_slot(slot);
+			if (ret == 0)
+				dev_info(&pdev->dev,
+					"Unloaded slot #%d\n", slotno);
+			else
+				dev_err(&pdev->dev,
+					"Failed to unload slot #%d\n", slotno);
+		} else {
+			ret = capemgr_remove_slot_no_lock(slot);
+			if (ret == 0)
+				dev_info(&pdev->dev,
+					"Removed slot #%d\n", slotno);
+			else
+				dev_err(&pdev->dev,
+					"Failed to remove slot #%d\n", slotno);
+		}
+		mutex_unlock(&info->slots_list_mutex);
+
+		return ret == 0 ? strlen(buf) : ret;
+	}
+
+	part_number = kstrdup(buf, GFP_KERNEL);
+	if (part_number == NULL)
+		return -ENOMEM;
+
+	/* remove trailing spaces dots and newlines */
+	s = part_number + strlen(part_number);
+	while (s > part_number &&
+			(isspace(s[-1]) || s[-1] == '\n' || s[-1] == '.'))
+		*--s = '\0';
+
+	version = strchr(part_number, ':');
+	if (version != NULL)
+		*version++ = '\0';
+
+	dev_info(&pdev->dev, "part_number '%s', version '%s'\n",
+			part_number, version ? version : "N/A");
+
+	pnode = pdev->dev.of_node;
+	node = NULL;
+	slot = NULL;
+	ret = 0;
+
+	/* no specific slot found, try immediate */
+	slot = capemgr_add_slot(info, NULL, part_number, version, 0);
+
+	if (IS_ERR_OR_NULL(slot)) {
+		dev_err(&pdev->dev, "Failed to add slot #%d\n",
+			atomic_read(&info->next_slot_nr) - 1);
+		ret = slot ? PTR_ERR(slot) : -ENODEV;
+		slot = NULL;
+		goto err_fail;
+	}
+
+	kfree(part_number);
+
+	ret = capemgr_load_slot(slot);
+	if (ret != 0)
+		capemgr_remove_slot(slot);
+
+	return ret == 0 ? strlen(buf) : ret;
+err_fail:
+	of_node_put(node);
+	of_node_put(slots_node);
+	kfree(part_number);
+	return ret;
+}
+
+/* verify the overlay */
+static int capemgr_verify_overlay(struct bone_cape_slot *slot)
+{
+	struct capemgr_info *info = slot->info;
+	struct device *dev = &info->pdev->dev;
+	struct bone_baseboard *bbrd = &info->baseboard;
+	struct device_node *node = slot->overlay;
+	struct property *prop;
+	struct bone_cape_slot *slotn;
+	int err, counta, countb, i, j;
+	const char *ra, *rb;
+
+	/* validate */
+	if (node == NULL) {
+		dev_err(dev, "slot #%d: No overlay for '%s'\n",
+				slot->slotno, slot->part_number);
+		return -EINVAL;
+	}
+
+	/* check if the slot is compatible with the board */
+	prop = of_find_property(node, "compatible", NULL);
+
+	/* no compatible property? */
+	if (prop == NULL) {
+		dev_err(dev, "slot #%d: No compatible property for '%s'\n",
+				slot->slotno, slot->part_number);
+		return -EINVAL;
+	}
+
+	/* verify that the cape is baseboard compatible */
+	if (of_multi_prop_cmp(prop, bbrd->compatible_name) != 0) {
+		dev_err(dev, "slot #%d: Incompatible with baseboard for '%s'\n",
+				slot->slotno, slot->part_number);
+		return -EINVAL;
+	}
+
+	/* count the strings */
+	counta = of_property_count_strings(node, "exclusive-use");
+	/* no valid property, or no resources; no matter, it's OK */
+	if (counta <= 0)
+		return 0;
+
+	/* and now check if there's a resource conflict */
+	err = 0;
+	mutex_lock(&info->slots_list_mutex);
+	for (i = 0; i < counta; i++) {
+
+		ra = NULL;
+		err = of_property_read_string_index(node, "exclusive-use",
+				i, &ra);
+		if (err != 0) {
+			dev_err(dev, "slot #%d: Could not read string #%d\n",
+					slot->slotno, i);
+			break;
+		}
+
+		list_for_each_entry(slotn, &info->slot_list, node) {
+
+			/* don't check against self */
+			if (slot == slotn)
+				continue;
+
+			/* only check against loaded or loading slots */
+			if (!slotn->loaded && !slotn->loading)
+				continue;
+
+			countb = of_property_count_strings(slotn->overlay,
+					"exclusive-use");
+			/* no valid property, or resources; it's OK */
+			if (countb <= 0)
+				continue;
+
+
+			for (j = 0; j < countb; j++) {
+
+				/* count the resources */
+				rb = NULL;
+				err = of_property_read_string_index(
+					slotn->overlay, "exclusive-use",
+						j, &rb);
+				if (err != 0) {
+					/* error, but we don't care */
+					err = 0;
+					break;
+				}
+
+				/* ignore case; just in case ;) */
+				if (strcasecmp(ra, rb) == 0) {
+
+					/* resource conflict */
+					err = -EEXIST;
+					dev_err(dev,
+						"slot #%d: %s conflict %s (#%d:%s)\n",
+						slot->slotno,
+						slot->part_number, ra,
+						slotn->slotno,
+						slotn->part_number);
+					goto out;
+				}
+			}
+		}
+	}
+out:
+	mutex_unlock(&info->slots_list_mutex);
+
+	return err;
+}
+
+static int capemgr_load_slot(struct bone_cape_slot *slot)
+{
+	struct capemgr_info *info = slot->info;
+	struct device *dev = &info->pdev->dev;
+	const char *dtbo;
+	int err;
+
+	if (slot->probe_failed) {
+		dev_err(dev, "slot #%d: probe failed for '%s'\n",
+			slot->slotno, slot->part_number);
+		return -ENODEV;
+	}
+
+	if (slot->loaded) {
+		dev_err(dev, "slot #%d: already loaded for '%s'\n",
+			slot->slotno, slot->part_number);
+		return -EAGAIN;
+	}
+
+	/* make sure we don't leak this on repeated calls */
+	kfree(slot->dtbo);
+	slot->dtbo = NULL;
+
+	dev_dbg(dev, "slot #%d: Requesting part number/version based '%s-%s.dtbo\n",
+			slot->slotno, slot->part_number, slot->version);
+
+	/* request the part number + .dtbo*/
+	slot->dtbo = kasprintf(GFP_KERNEL, "%s-%s.dtbo",
+			slot->part_number, slot->version);
+	if (slot->dtbo == NULL) {
+		dev_err(dev, "slot #%d: Failed to get dtbo '%s'\n",
+				slot->slotno, dtbo);
+		return -ENOMEM;
+	}
+
+	dev_dbg(dev, "slot #%d: Requesting firmware '%s' for board-name '%s', version '%s'%s\n",
+			slot->slotno,
+			slot->dtbo, slot->board_name, slot->version,
+			system_state == SYSTEM_BOOTING ? " - booting" : "");
+
+	err = request_firmware_direct(&slot->fw, slot->dtbo, dev);
+	if (err != 0) {
+		dev_dbg(dev, "failed to load firmware '%s'\n", slot->dtbo);
+		goto err_fail_no_fw;
+	}
+
+	dev_dbg(dev, "slot #%d: dtbo '%s' loaded; converting to live tree\n",
+			slot->slotno, slot->dtbo);
+
+	of_fdt_unflatten_tree((void *)slot->fw->data, &slot->overlay);
+	if (slot->overlay == NULL) {
+		dev_err(dev, "slot #%d: Failed to unflatten\n",
+				slot->slotno);
+		err = -EINVAL;
+		goto err_fail;
+	}
+
+	/* mark it as detached */
+	of_node_set_flag(slot->overlay, OF_DETACHED);
+
+	/* perform resolution */
+	err = of_resolve_phandles(slot->overlay);
+	if (err != 0) {
+		dev_err(dev, "slot #%d: Failed to resolve tree\n",
+				slot->slotno);
+		goto err_fail;
+	}
+
+	err = capemgr_verify_overlay(slot);
+	if (err != 0) {
+		dev_err(dev, "slot #%d: Failed verification\n",
+				slot->slotno);
+		goto err_fail;
+	}
+
+	err = of_overlay_create(slot->overlay);
+	if (err < 0) {
+		dev_err(dev, "slot #%d: Failed to create overlay\n",
+				slot->slotno);
+		goto err_fail;
+	}
+	slot->overlay_id = err;
+
+	slot->loading = 0;
+	slot->loaded = 1;
+
+	dev_info(dev, "slot #%d: dtbo '%s' loaded; overlay id #%d\n",
+			slot->slotno, slot->dtbo, slot->overlay_id);
+
+	return 0;
+
+err_fail:
+
+	/* TODO: free the overlay, we can't right now cause
+	 * the unflatten method does not track it */
+	slot->overlay = NULL;
+
+	release_firmware(slot->fw);
+	slot->fw = NULL;
+
+err_fail_no_fw:
+	slot->loading = 0;
+	return err;
+}
+
+static int capemgr_unload_slot(struct bone_cape_slot *slot)
+{
+	if (!slot->loaded || slot->overlay_id == -1)
+		return -EINVAL;
+
+	of_overlay_destroy(slot->overlay_id);
+	slot->overlay_id = -1;
+
+	slot->loaded = 0;
+
+	return 0;
+
+}
+
+/* slots_list_mutex must be taken */
+static int capemgr_remove_slot_no_lock(struct bone_cape_slot *slot)
+{
+	struct capemgr_info *info = slot->info;
+	struct device *dev = &info->pdev->dev;
+	int ret;
+
+	if (slot == NULL)
+		return 0;
+
+	if (slot->loaded && slot->overlay_id >= 0) {
+		/* unload just in case */
+		ret = capemgr_unload_slot(slot);
+		if (ret != 0) {
+			dev_err(dev, "Unable to unload slot #%d\n",
+				slot->slotno);
+			return ret;
+		}
+	}
+
+	/* if probed OK, remove the sysfs nodes */
+	if (slot->probed && !slot->probe_failed)
+		bone_cape_slot_sysfs_unregister(slot);
+
+	/* remove it from the list */
+	list_del(&slot->node);
+
+	if (slot->eeprom_cell)
+		eeprom_cell_put(slot->eeprom_cell);
+	devm_kfree(dev, slot);
+	return 0;
+}
+
+static int capemgr_remove_slot(struct bone_cape_slot *slot)
+{
+	struct capemgr_info *info = slot->info;
+	int ret;
+
+	mutex_lock(&info->slots_list_mutex);
+	ret = capemgr_remove_slot_no_lock(slot);
+	mutex_unlock(&info->slots_list_mutex);
+
+	return ret;
+}
+
+static int bone_slot_fill_override(struct bone_cape_slot *slot,
+		struct device_node *node,
+		const char *part_number, const char *version)
+{
+	const struct ee_field *sig_field;
+	struct property *prop;
+	int i, len, has_part_number;
+	u32 val;
+	char *p;
+
+	slot->probe_failed = 0;
+	slot->probed = 0;
+
+	/* zero out signature */
+	memset(slot->signature, 0,
+			sizeof(slot->signature));
+
+	/* first, fill in all with override defaults */
+	for (i = 0; i < ARRAY_SIZE(cape_sig_fields); i++) {
+
+		sig_field = &cape_sig_fields[i];
+
+		/* point to the entry */
+		p = slot->signature + sig_field->start;
+
+		if (sig_field->override)
+			memcpy(p, sig_field->override,
+					sig_field->size);
+		else
+			memset(p, 0, sig_field->size);
+	}
+
+	/* and now, fill any override data from the node */
+	has_part_number = 0;
+	if (node != NULL) {
+		for (i = 0; i < ARRAY_SIZE(cape_sig_fields); i++) {
+
+			sig_field = &cape_sig_fields[i];
+
+			/* find property with the same name (if any) */
+			prop = of_find_property(node, sig_field->name, NULL);
+			if (prop == NULL)
+				continue;
+
+			/* point to the entry */
+			p = slot->signature + sig_field->start;
+
+			/* copy and zero out any remainder */
+			len = prop->length;
+			if (prop->length > sig_field->size)
+				len = sig_field->size;
+			memcpy(p, prop->value, len);
+			if (len < sig_field->size)
+				memset(p + len, 0, sig_field->size - len);
+
+			/* remember if we got a part number which is required */
+			if (i == CAPE_EE_FIELD_PART_NUMBER && len > 0)
+				has_part_number = 1;
+		}
+
+		if (of_property_read_u32(node, "priority", &val) != 0)
+			val = 0;
+		slot->priority = val;
+	}
+
+	/* if a part_number is supplied use it */
+	len = part_number ? strlen(part_number) : 0;
+	if (len > 0) {
+		sig_field = &cape_sig_fields[CAPE_EE_FIELD_PART_NUMBER];
+
+		/* point to the entry */
+		p = slot->signature + sig_field->start;
+
+		/* copy and zero out any remainder */
+		if (len > sig_field->size)
+			len = sig_field->size;
+		memcpy(p, part_number, len);
+		if (len < sig_field->size)
+			memset(p + len, 0, sig_field->size - len);
+
+		has_part_number = 1;
+	}
+
+	/* if a version is supplied use it */
+	len = version ? strlen(version) : 0;
+	if (len > 0) {
+		sig_field = &cape_sig_fields[CAPE_EE_FIELD_VERSION];
+
+		/* point to the entry */
+		p = slot->signature + sig_field->start;
+
+		/* copy and zero out any remainder */
+		if (len > sig_field->size)
+			len = sig_field->size;
+		memcpy(p, version, len);
+		if (len < sig_field->size)
+			memset(p + len, 0, sig_field->size - len);
+	}
+
+	/* we must have a part number */
+	if (!has_part_number)
+		return -EINVAL;
+
+	slot->override = 1;
+
+	return 0;
+}
+
+static struct bone_cape_slot *
+capemgr_add_slot(struct capemgr_info *info, struct device_node *node,
+		const char *part_number, const char *version, int prio)
+{
+	struct bone_cape_slot *slot;
+	struct device *dev = &info->pdev->dev;
+	int slotno;
+	int ret;
+
+	slotno = atomic_inc_return(&info->next_slot_nr) - 1;
+
+	slot = devm_kzalloc(dev, sizeof(*slot), GFP_KERNEL);
+	if (slot == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	slot->info = info;
+	slot->slotno = slotno;
+	slot->priority = prio;
+	slot->overlay_id = -1;
+
+	if (node) {
+		slot->eeprom_cell = of_eeprom_cell_get(node, "eeprom");
+		if (IS_ERR(slot->eeprom_cell)) {
+			ret = PTR_ERR(slot->eeprom_cell);
+			if (ret != -EPROBE_DEFER)
+				dev_err(dev, "Failed to get slot eeprom cell\n");
+			slot->eeprom_cell = NULL;
+			goto err_out;
+		}
+	} else {
+		dev_info(dev, "slot #%d: override\n", slotno);
+
+		/* fill in everything with defaults first */
+		ret = bone_slot_fill_override(slot, node, part_number, version);
+		if (ret != 0) {
+			dev_err(dev, "slot #%d: override failed\n", slotno);
+			goto err_out;
+		}
+	}
+
+	ret = bone_slot_scan(slot);
+	if (ret != 0) {
+
+		if (!slot->probe_failed) {
+			dev_err(dev, "slot #%d: scan failed\n",
+					slotno);
+			goto err_out;
+		}
+
+		dev_err(dev, "slot #%d: No cape found\n", slotno);
+		/* but all is fine */
+	} else {
+
+		dev_info(dev, "slot #%d: '%s'\n",
+				slotno, slot->text_id);
+
+		ret = bone_cape_slot_sysfs_register(slot);
+		if (ret != 0) {
+			dev_err(dev, "slot #%d: sysfs register failed\n",
+					slotno);
+			goto err_out;
+		}
+
+	}
+
+	/* add to the slot list */
+	mutex_lock(&info->slots_list_mutex);
+	list_add_tail(&slot->node, &info->slot_list);
+	mutex_unlock(&info->slots_list_mutex);
+
+	return slot;
+
+err_out:
+	if (slot->eeprom_cell)
+		eeprom_cell_put(slot->eeprom_cell);
+	devm_kfree(dev, slot);
+	return ERR_PTR(ret);
+}
+
+/* return 1 if it makes sense to retry loading */
+static int retry_loading_condition(struct bone_cape_slot *slot)
+{
+	struct capemgr_info *info = slot->info;
+	struct device *dev = &info->pdev->dev;
+	struct bone_cape_slot *slotn;
+	int ret;
+
+	dev_dbg(dev, "loader: retry_loading slot-%d %s:%s (prio %d)\n",
+			slot->slotno, slot->part_number, slot->version,
+			slot->priority);
+
+	mutex_lock(&info->slots_list_mutex);
+	ret = 0;
+	list_for_each_entry(slotn, &info->slot_list, node) {
+		/* if same slot or not loading skip */
+		if (!slotn->loading || slotn->retry_loading)
+			continue;
+		/* at least one cape is still loading (without retrying) */
+		ret = 1;
+	}
+	mutex_unlock(&info->slots_list_mutex);
+	return ret;
+}
+
+/* return 1 if this slot is clear to try to load now */
+static int clear_to_load_condition(struct bone_cape_slot *slot)
+{
+	struct capemgr_info *info = slot->info;
+	int my_prio = slot->priority;
+	struct device *dev = &info->pdev->dev;
+	int ret;
+
+	dev_dbg(dev, "loader: check slot-%d %s:%s (prio %d)\n", slot->slotno,
+			slot->part_number, slot->version, slot->priority);
+
+	mutex_lock(&info->slots_list_mutex);
+	ret = 1;
+	list_for_each_entry(slot, &info->slot_list, node) {
+		/* if any slot is loading with lowest priority */
+		if (!slot->loading)
+			continue;
+		if (slot->priority < my_prio) {
+			ret = 0;
+			break;
+		}
+	}
+	mutex_unlock(&info->slots_list_mutex);
+	return ret;
+}
+
+static int capemgr_loader(void *data)
+{
+	struct bone_cape_slot *slot = data;
+	struct capemgr_info *info = slot->info;
+	struct device *dev = &info->pdev->dev;
+	int ret, done, other_loading, booting;
+
+	done = 0;
+
+	slot->retry_loading = 0;
+
+	dev_dbg(dev, "loader: before slot-%d %s:%s (prio %d)\n", slot->slotno,
+			slot->part_number, slot->version, slot->priority);
+
+	/*
+	 * We have a basic priority based arbitration system
+	 * Slots have priorities, so the lower priority ones
+	 * should start loading first. So each time we end up
+	 * here.
+	 */
+	ret = wait_event_interruptible(info->load_wq,
+			clear_to_load_condition(slot));
+	if (ret < 0) {
+		dev_warn(dev, "loader, Signal pending\n");
+		return ret;
+	}
+
+	dev_dbg(dev, "loader: after slot-%d %s:%s (prio %d)\n", slot->slotno,
+			slot->part_number, slot->version, slot->priority);
+
+	/* using the return value */
+	ret = capemgr_load_slot(slot);
+
+	/* wake up all just in case */
+	wake_up_interruptible_all(&info->load_wq);
+
+	if (ret == 0)
+		goto done;
+
+	dev_dbg(dev, "loader: retrying slot-%d %s:%s (prio %d)\n", slot->slotno,
+			slot->part_number, slot->version, slot->priority);
+
+	/* first attempt has failed; now try each time there's any change */
+	slot->retry_loading = 1;
+
+	for (;;) {
+		booting = (system_state == SYSTEM_BOOTING);
+		other_loading = retry_loading_condition(slot);
+		if (!booting && !other_loading)
+			break;
+
+		/* simple wait for someone to kick us */
+		if (other_loading) {
+			DEFINE_WAIT(__wait);
+
+			prepare_to_wait(&info->load_wq, &__wait,
+					TASK_INTERRUPTIBLE);
+			finish_wait(&info->load_wq, &__wait);
+		} else {
+			/* always delay when booting */
+			msleep(boot_scan_period);
+		}
+
+		if (signal_pending(current)) {
+			dev_warn(dev, "loader, Signal pending\n");
+			ret = -ERESTARTSYS;
+			goto done;
+		}
+
+		/* using the return value */
+		ret = capemgr_load_slot(slot);
+		if (ret == 0)
+			goto done;
+
+		/* wake up all just in case */
+		wake_up_interruptible_all(&info->load_wq);
+	}
+
+done:
+	slot->loading = 0;
+	slot->retry_loading = 0;
+
+	if (ret == 0) {
+		dev_dbg(dev, "loader: done slot-%d %s:%s (prio %d)\n",
+			slot->slotno, slot->part_number, slot->version,
+			slot->priority);
+	} else {
+		dev_err(dev, "loader: failed to load slot-%d %s:%s (prio %d)\n",
+			slot->slotno, slot->part_number, slot->version,
+			slot->priority);
+
+		/* if it's a override slot remove it */
+		if (slot->override)
+			capemgr_remove_slot(slot);
+	}
+
+	return ret;
+}
+
+static int
+capemgr_probe(struct platform_device *pdev)
+{
+	struct capemgr_info *info;
+	struct bone_baseboard *bbrd;
+	struct bone_cape_slot *slot;
+	struct device_node *pnode = pdev->dev.of_node;
+	struct device_node *baseboardmaps_node;
+	struct device_node *slots_node, *node;
+	const char *part_number;
+	const char *version;
+	const char *board_name;
+	const char *compatible_name;
+	int ret, len, prio;
+	long val;
+	char *wbuf, *s, *p, *e;
+
+	/* we don't use platform_data at all; we require OF */
+	if (pnode == NULL)
+		return -ENOTSUPP;
+
+	info = devm_kzalloc(&pdev->dev,
+			sizeof(struct capemgr_info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->pdev = pdev;
+	platform_set_drvdata(pdev, info);
+
+	atomic_set(&info->next_slot_nr, 0);
+	INIT_LIST_HEAD(&info->slot_list);
+	mutex_init(&info->slots_list_mutex);
+
+	init_waitqueue_head(&info->load_wq);
+
+	baseboardmaps_node = NULL;
+
+	/* find the baseboard */
+	bbrd = &info->baseboard;
+
+	baseboardmaps_node = of_get_child_by_name(pnode, "baseboardmaps");
+	if (baseboardmaps_node == NULL) {
+		dev_err(&pdev->dev, "Failed to get baseboardmaps node");
+		ret = -ENODEV;
+		goto err_exit;
+	}
+
+	bbrd->eeprom_cell = of_eeprom_cell_get(pnode, "eeprom");
+	if (IS_ERR(bbrd->eeprom_cell)) {
+		ret = PTR_ERR(bbrd->eeprom_cell);
+		if (ret != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "Failed to get baseboard eeprom cell\n");
+		bbrd->eeprom_cell = NULL;
+		goto err_exit;
+	}
+
+	ret = bone_baseboard_scan(bbrd);
+	if (ret != 0) {
+		dev_err(&pdev->dev, "Failed to scan baseboard eeprom\n");
+		goto err_exit;
+	}
+
+	dev_info(&pdev->dev, "Baseboard: '%s'\n", bbrd->text_id);
+
+	board_name = NULL;
+	compatible_name = NULL;
+	for_each_child_of_node(baseboardmaps_node, node) {
+		/* there must be board-name */
+		if (of_property_read_string(node, "board-name",
+					&board_name) != 0 ||
+		    of_property_read_string(node, "compatible-name",
+					&compatible_name) != 0)
+			continue;
+
+		if (strcmp(bbrd->board_name, board_name) == 0)
+			break;
+	}
+	of_node_put(baseboardmaps_node);
+	baseboardmaps_node = NULL;
+
+	if (node == NULL) {
+		dev_err(&pdev->dev, "Failed to find compatible map for %s\n",
+				bbrd->board_name);
+		ret = -ENODEV;
+		goto err_exit;
+	}
+	bbrd->compatible_name = kstrdup(compatible_name, GFP_KERNEL);
+	if (bbrd->compatible_name == NULL) {
+		ret = -ENOMEM;
+		goto err_exit;
+	}
+	of_node_put(node);
+
+	dev_info(&pdev->dev, "compatible-baseboard=%s\n",
+			bbrd->compatible_name);
+
+	/* iterate over any slots */
+	slots_node = of_get_child_by_name(pnode, "slots");
+	if (slots_node != NULL) {
+		for_each_child_of_node(slots_node, node) {
+
+			slot = capemgr_add_slot(info, node, NULL, NULL, 0);
+			if (IS_ERR(slot)) {
+				dev_err(&pdev->dev, "Failed to add slot #%d\n",
+					atomic_read(&info->next_slot_nr));
+				ret = PTR_ERR(slot);
+				goto err_exit;
+			}
+			/* note that slot may be NULL (means it was disabled) */
+		}
+		of_node_put(slots_node);
+	}
+	slots_node = NULL;
+
+	/* iterate over enable_partno (if there) */
+	if (enable_partno && strlen(enable_partno) > 0) {
+
+		/* allocate a temporary buffer */
+		wbuf = devm_kzalloc(&pdev->dev, PAGE_SIZE, GFP_KERNEL);
+		if (wbuf == NULL) {
+			ret = -ENOMEM;
+			goto err_exit;
+		}
+
+		/* add any enable_partno capes */
+		s = enable_partno;
+		while (*s) {
+			/* form is PART[:REV[:PRIO]],PART.. */
+			p = strchr(s, ',');
+			if (p == NULL)
+				e = s + strlen(s);
+			else
+				e = p;
+
+			/* copy to temp buffer */
+			len = e - s;
+			if (len >= PAGE_SIZE - 1)
+				len = PAGE_SIZE - 1;
+			memcpy(wbuf, s, len);
+			wbuf[len] = '\0';
+
+			/* move to the next */
+			s = *e ? e + 1 : e;
+
+			part_number = wbuf;
+
+			/* default version is NULL & prio is 0 */
+			version = NULL;
+			prio = 0;
+
+			/* now split the rev & prio part */
+			p = strchr(wbuf, ':');
+			if (p != NULL) {
+				*p++ = '\0';
+				if (*p != ':')
+					version = p;
+				p = strchr(p, ':');
+				if (p != NULL) {
+					*p++ = '\0';
+					ret = kstrtol(p, 10, &val);
+					if (ret == 0)
+						prio = val;
+				}
+			}
+
+			dev_info(&pdev->dev,
+				"enabled_partno PARTNO '%s' VER '%s' PR '%d'\n",
+					part_number,
+					version ? version : "N/A", prio);
+
+			/* only immediate slots are allowed here */
+			slot = capemgr_add_slot(info, NULL,
+					part_number, version, prio);
+
+			/* we continue even in case of an error */
+			if (IS_ERR_OR_NULL(slot)) {
+				dev_warn(&pdev->dev, "Failed to add slot #%d\n",
+					atomic_read(&info->next_slot_nr) - 1);
+			}
+		}
+
+		devm_kfree(&pdev->dev, wbuf);
+	}
+
+	pm_runtime_enable(&pdev->dev);
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (IS_ERR_VALUE(ret)) {
+		dev_err(&pdev->dev, "Failed to pm_runtime_get_sync()\n");
+		goto err_exit;
+	}
+
+	pm_runtime_put(&pdev->dev);
+
+	/* it is safe to create the attribute groups */
+	ret = sysfs_create_groups(&pdev->dev.kobj, attr_groups);
+	if (ret != 0) {
+		dev_err(&pdev->dev, "Failed to create sysfs attributes\n");
+		goto err_exit;
+	}
+	/* automatically cleared by driver core now */
+	pdev->dev.groups = attr_groups;
+
+	/* now load each (take lock to be sure */
+	mutex_lock(&info->slots_list_mutex);
+
+	list_for_each_entry(slot, &info->slot_list, node) {
+
+		/* if matches the disabled ones skip */
+		if (bone_match_cape(disable_partno, slot->part_number,
+					slot->version)) {
+			dev_info(&pdev->dev,
+				"Skipping loading of disabled cape with part# %s\n",
+				slot->part_number);
+			slot->disabled = 1;
+			continue;
+		}
+
+		if (!slot->probe_failed && !slot->loaded)
+			slot->loading = 1;
+	}
+
+	/* now start the loader thread(s) (all at once) */
+	list_for_each_entry(slot, &info->slot_list, node) {
+
+		if (!slot->loading)
+			continue;
+
+		slot->loader_thread = kthread_run(capemgr_loader,
+				slot, "capemgr-loader-%d",
+				slot->slotno);
+		if (IS_ERR(slot->loader_thread)) {
+			dev_warn(&pdev->dev, "slot #%d: Failed to start loader\n",
+					slot->slotno);
+			slot->loader_thread = NULL;
+		}
+	}
+	mutex_unlock(&info->slots_list_mutex);
+
+	dev_info(&pdev->dev, "initialized OK.\n");
+
+	return 0;
+
+err_exit:
+	if (bbrd->eeprom_cell)
+		eeprom_cell_put(bbrd->eeprom_cell);
+	of_node_put(baseboardmaps_node);
+	platform_set_drvdata(pdev, NULL);
+	devm_kfree(&pdev->dev, info);
+
+	return ret;
+}
+
+static int capemgr_remove(struct platform_device *pdev)
+{
+	struct capemgr_info *info = platform_get_drvdata(pdev);
+	struct bone_baseboard *bbrd = &info->baseboard;
+	struct bone_cape_slot *slot, *slotn;
+	int ret;
+
+	mutex_lock(&info->slots_list_mutex);
+	list_for_each_entry_safe(slot, slotn, &info->slot_list, node)
+		capemgr_remove_slot_no_lock(slot);
+	mutex_unlock(&info->slots_list_mutex);
+
+	platform_set_drvdata(pdev, NULL);
+
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (IS_ERR_VALUE(ret))
+		return ret;
+
+	pm_runtime_put(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
+	if (bbrd->eeprom_cell)
+		eeprom_cell_put(bbrd->eeprom_cell);
+	devm_kfree(&pdev->dev, info);
+
+	return 0;
+}
+
+static struct platform_driver capemgr_driver = {
+	.probe		= capemgr_probe,
+	.remove		= capemgr_remove,
+	.driver		= {
+		.name	= "bone_capemgr",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(capemgr_of_match),
+	},
+};
+
+module_platform_driver(capemgr_driver);
+
+MODULE_AUTHOR("Pantelis Antoniou");
+MODULE_DESCRIPTION("Beaglebone cape manager");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:bone_capemgr");
-- 
1.7.12

Re: [PATCH 1/5] misc: Beaglebone capemanager

[Greg Kroah-Hartman]

On Wed, May 13, 2015 at 10:59:41AM +0300, Pantelis Antoniou wrote:
> A cape loader based on DT overlays and DT objects.
> 
> This is the beaglebone cape manager which allows capes to be automatically
> probed and instantiated via means of a device tree overlay deduced from
> the part-number and version contained on the cape's EEPROM.
> 
> The reference manual contains information about the specification
> and the contents of the EEPROM.
> 
> http://beagleboard.org/static/beaglebone/latest/Docs/Hardware/BONE_SRM.pdf
> 
> Documentation about the workings of the cape manager is located
> in Documentation/misc-devices/bone_capemgr.txt
> 
> This driver is using the EEPROM framework interface to retrieve
> the data stored on the baseboard and cape EEPROMs.
> 
> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> ---
>  drivers/misc/Kconfig        |   10 +
>  drivers/misc/Makefile       |    1 +
>  drivers/misc/bone_capemgr.c | 1926 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1937 insertions(+)
>  create mode 100644 drivers/misc/bone_capemgr.c
> 
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 006242c..f9e09e1 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -515,6 +515,16 @@ config VEXPRESS_SYSCFG
>  	  bus. System Configuration interface is one of the possible means
>  	  of generating transactions on this bus.
>  
> +config BONE_CAPEMGR
> +	tristate "Beaglebone cape manager"
> +	depends on ARCH_OMAP2PLUS && OF
> +	select EEPROM
> +	select OF_OVERLAY
> +	default n

N is always the default, please remove.

> +	help
> +	  Say Y here to include support for automatic loading of
> +	  beaglebone capes.
> +

What about if it's a module?


>  source "drivers/misc/c2port/Kconfig"
>  source "drivers/misc/eeprom/Kconfig"
>  source "drivers/misc/cb710/Kconfig"
> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
> index 7d5c4cd..659b78b 100644
> --- a/drivers/misc/Makefile
> +++ b/drivers/misc/Makefile
> @@ -56,3 +56,4 @@ obj-$(CONFIG_GENWQE)		+= genwqe/
>  obj-$(CONFIG_ECHO)		+= echo/
>  obj-$(CONFIG_VEXPRESS_SYSCFG)	+= vexpress-syscfg.o
>  obj-$(CONFIG_CXL_BASE)		+= cxl/
> +obj-$(CONFIG_BONE_CAPEMGR)	+= bone_capemgr.o
> diff --git a/drivers/misc/bone_capemgr.c b/drivers/misc/bone_capemgr.c
> new file mode 100644
> index 0000000..423719c
> --- /dev/null
> +++ b/drivers/misc/bone_capemgr.c
> @@ -0,0 +1,1926 @@
> +/*
> + * TI Beaglebone cape manager
> + *
> + * Copyright (C) 2012 Texas Instruments Inc.
> + * Copyright (C) 2012-2015 Konsulko Group.
> + * Author: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.

I have to ask, do you really mean, "or any later version"?


> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/completion.h>
> +#include <linux/platform_device.h>
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_fdt.h>
> +#include <linux/slab.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/pinctrl/consumer.h>
> +#include <linux/firmware.h>
> +#include <linux/err.h>
> +#include <linux/ctype.h>
> +#include <linux/string.h>
> +#include <linux/memory.h>
> +#include <linux/kthread.h>
> +#include <linux/wait.h>
> +#include <linux/file.h>
> +#include <linux/fs.h>
> +#include <linux/eeprom-consumer.h>
> +
> +/* disabled capes */
> +static char *disable_partno;
> +module_param(disable_partno, charp, 0444);
> +MODULE_PARM_DESC(disable_partno,
> +		"Comma delimited list of PART-NUMBER[:REV] of disabled capes");
> +
> +/* enable capes */
> +static char *enable_partno;
> +module_param(enable_partno, charp, 0444);
> +MODULE_PARM_DESC(enable_partno,
> +		"Comma delimited list of PART-NUMBER[:REV] of enabled capes");
> +
> +/* delay to scan on boot until rootfs appears */
> +static int boot_scan_period = 1000;
> +module_param(boot_scan_period, int, 0444);
> +MODULE_PARM_DESC(boot_scan_period,
> +		"boot scan period until rootfs firmware is available");

Ick, no module parameters please, can't we drop these?

And we have a rootfs delay option already for the whole system, this
module shouldn't need a special one.

thanks,

greg k-h

Re: [PATCH 1/5] misc: Beaglebone capemanager

[Pantelis Antoniou]

Hi Greg,

> On May 13, 2015, at 14:55 , Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> 
> On Wed, May 13, 2015 at 10:59:41AM +0300, Pantelis Antoniou wrote:
>> A cape loader based on DT overlays and DT objects.
>> 
>> This is the beaglebone cape manager which allows capes to be automatically
>> probed and instantiated via means of a device tree overlay deduced from
>> the part-number and version contained on the cape's EEPROM.
>> 
>> The reference manual contains information about the specification
>> and the contents of the EEPROM.
>> 
>> http://beagleboard.org/static/beaglebone/latest/Docs/Hardware/BONE_SRM.pdf
>> 
>> Documentation about the workings of the cape manager is located
>> in Documentation/misc-devices/bone_capemgr.txt
>> 
>> This driver is using the EEPROM framework interface to retrieve
>> the data stored on the baseboard and cape EEPROMs.
>> 
>> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
>> ---
>> drivers/misc/Kconfig        |   10 +
>> drivers/misc/Makefile       |    1 +
>> drivers/misc/bone_capemgr.c | 1926 +++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 1937 insertions(+)
>> create mode 100644 drivers/misc/bone_capemgr.c
>> 
>> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
>> index 006242c..f9e09e1 100644
>> --- a/drivers/misc/Kconfig
>> +++ b/drivers/misc/Kconfig
>> @@ -515,6 +515,16 @@ config VEXPRESS_SYSCFG
>> 	  bus. System Configuration interface is one of the possible means
>> 	  of generating transactions on this bus.
>> 
>> +config BONE_CAPEMGR
>> +	tristate "Beaglebone cape manager"
>> +	depends on ARCH_OMAP2PLUS && OF
>> +	select EEPROM
>> +	select OF_OVERLAY
>> +	default n
> 
> N is always the default, please remove.
> 

OK

>> +	help
>> +	  Say Y here to include support for automatic loading of
>> +	  beaglebone capes.
>> +
> 
> What about if it's a module?
> 
> 

It should work but it’s going to be weird (i.e. no-one has used it as such).
I’ll update the blurb.

>> source "drivers/misc/c2port/Kconfig"
>> source "drivers/misc/eeprom/Kconfig"
>> source "drivers/misc/cb710/Kconfig"
>> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
>> index 7d5c4cd..659b78b 100644
>> --- a/drivers/misc/Makefile
>> +++ b/drivers/misc/Makefile
>> @@ -56,3 +56,4 @@ obj-$(CONFIG_GENWQE)		+= genwqe/
>> obj-$(CONFIG_ECHO)		+= echo/
>> obj-$(CONFIG_VEXPRESS_SYSCFG)	+= vexpress-syscfg.o
>> obj-$(CONFIG_CXL_BASE)		+= cxl/
>> +obj-$(CONFIG_BONE_CAPEMGR)	+= bone_capemgr.o
>> diff --git a/drivers/misc/bone_capemgr.c b/drivers/misc/bone_capemgr.c
>> new file mode 100644
>> index 0000000..423719c
>> --- /dev/null
>> +++ b/drivers/misc/bone_capemgr.c
>> @@ -0,0 +1,1926 @@
>> +/*
>> + * TI Beaglebone cape manager
>> + *
>> + * Copyright (C) 2012 Texas Instruments Inc.
>> + * Copyright (C) 2012-2015 Konsulko Group.
>> + * Author: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
> 
> I have to ask, do you really mean, "or any later version”?
> 

Yes, this is purely a community thing. No evil vendor at play at all.
 
> 
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/delay.h>
>> +#include <linux/err.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/completion.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/clk.h>
>> +#include <linux/io.h>
>> +#include <linux/of.h>
>> +#include <linux/of_device.h>
>> +#include <linux/of_fdt.h>
>> +#include <linux/slab.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/pinctrl/consumer.h>
>> +#include <linux/firmware.h>
>> +#include <linux/err.h>
>> +#include <linux/ctype.h>
>> +#include <linux/string.h>
>> +#include <linux/memory.h>
>> +#include <linux/kthread.h>
>> +#include <linux/wait.h>
>> +#include <linux/file.h>
>> +#include <linux/fs.h>
>> +#include <linux/eeprom-consumer.h>
>> +
>> +/* disabled capes */
>> +static char *disable_partno;
>> +module_param(disable_partno, charp, 0444);
>> +MODULE_PARM_DESC(disable_partno,
>> +		"Comma delimited list of PART-NUMBER[:REV] of disabled capes");
>> +
>> +/* enable capes */
>> +static char *enable_partno;
>> +module_param(enable_partno, charp, 0444);
>> +MODULE_PARM_DESC(enable_partno,
>> +		"Comma delimited list of PART-NUMBER[:REV] of enabled capes");
>> +
>> +/* delay to scan on boot until rootfs appears */
>> +static int boot_scan_period = 1000;
>> +module_param(boot_scan_period, int, 0444);
>> +MODULE_PARM_DESC(boot_scan_period,
>> +		"boot scan period until rootfs firmware is available");
> 
> Ick, no module parameters please, can't we drop these?
> 

In a nutshell, no :)

These has to be way to control whether a cape is disabled (if found) and enabled (if the manufacturer in it’s infinite wisdom removed the EEPROM to save $0.01 per cape).

The easiest way to achieve this is with the kernel command line.

> And we have a rootfs delay option already for the whole system, this
> module shouldn't need a special one.
> 

No, that won’t work.

You see the problem is as follows.

The capemanager is not built as a module, it is builtin.

By the time the probe method is called the rootfs has no been mounted yet.
This is actually what we want for the cases where the rootfs resides on a cape and
the cape’s dtbo firmware file is built-in the kernel image.

This does not work when the firmware file is located in the rootfs filesystem, since
the call to request_firmware will fail at that time.

That option controls the polling delay until the system boot state indicates that the
rootfs is available and the call will succeed.

There are lots of warts in our firmware loader.

> thanks,
> 
> greg k-h

Regards

— Pantelis

Re: [PATCH 1/5] misc: Beaglebone capemanager

[Greg Kroah-Hartman]

On Wed, May 13, 2015 at 03:10:25PM +0300, Pantelis Antoniou wrote:
> Hi Greg,
> 
> > On May 13, 2015, at 14:55 , Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> > 
> > On Wed, May 13, 2015 at 10:59:41AM +0300, Pantelis Antoniou wrote:
> >> A cape loader based on DT overlays and DT objects.
> >> 
> >> This is the beaglebone cape manager which allows capes to be automatically
> >> probed and instantiated via means of a device tree overlay deduced from
> >> the part-number and version contained on the cape's EEPROM.
> >> 
> >> The reference manual contains information about the specification
> >> and the contents of the EEPROM.
> >> 
> >> http://beagleboard.org/static/beaglebone/latest/Docs/Hardware/BONE_SRM.pdf
> >> 
> >> Documentation about the workings of the cape manager is located
> >> in Documentation/misc-devices/bone_capemgr.txt
> >> 
> >> This driver is using the EEPROM framework interface to retrieve
> >> the data stored on the baseboard and cape EEPROMs.
> >> 
> >> Signed-off-by: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
> >> ---
> >> drivers/misc/Kconfig        |   10 +
> >> drivers/misc/Makefile       |    1 +
> >> drivers/misc/bone_capemgr.c | 1926 +++++++++++++++++++++++++++++++++++++++++++
> >> 3 files changed, 1937 insertions(+)
> >> create mode 100644 drivers/misc/bone_capemgr.c
> >> 
> >> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> >> index 006242c..f9e09e1 100644
> >> --- a/drivers/misc/Kconfig
> >> +++ b/drivers/misc/Kconfig
> >> @@ -515,6 +515,16 @@ config VEXPRESS_SYSCFG
> >> 	  bus. System Configuration interface is one of the possible means
> >> 	  of generating transactions on this bus.
> >> 
> >> +config BONE_CAPEMGR
> >> +	tristate "Beaglebone cape manager"
> >> +	depends on ARCH_OMAP2PLUS && OF
> >> +	select EEPROM
> >> +	select OF_OVERLAY
> >> +	default n
> > 
> > N is always the default, please remove.
> > 
> 
> OK
> 
> >> +	help
> >> +	  Say Y here to include support for automatic loading of
> >> +	  beaglebone capes.
> >> +
> > 
> > What about if it's a module?
> > 
> > 
> 
> It should work but it’s going to be weird (i.e. no-one has used it as such).
> I’ll update the blurb.

You are saying it is a valid config option, so please test it as such,
or if it's not a valid config option, don't allow it.

> >> source "drivers/misc/c2port/Kconfig"
> >> source "drivers/misc/eeprom/Kconfig"
> >> source "drivers/misc/cb710/Kconfig"
> >> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
> >> index 7d5c4cd..659b78b 100644
> >> --- a/drivers/misc/Makefile
> >> +++ b/drivers/misc/Makefile
> >> @@ -56,3 +56,4 @@ obj-$(CONFIG_GENWQE)		+= genwqe/
> >> obj-$(CONFIG_ECHO)		+= echo/
> >> obj-$(CONFIG_VEXPRESS_SYSCFG)	+= vexpress-syscfg.o
> >> obj-$(CONFIG_CXL_BASE)		+= cxl/
> >> +obj-$(CONFIG_BONE_CAPEMGR)	+= bone_capemgr.o
> >> diff --git a/drivers/misc/bone_capemgr.c b/drivers/misc/bone_capemgr.c
> >> new file mode 100644
> >> index 0000000..423719c
> >> --- /dev/null
> >> +++ b/drivers/misc/bone_capemgr.c
> >> @@ -0,0 +1,1926 @@
> >> +/*
> >> + * TI Beaglebone cape manager
> >> + *
> >> + * Copyright (C) 2012 Texas Instruments Inc.
> >> + * Copyright (C) 2012-2015 Konsulko Group.
> >> + * Author: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
> >> + *
> >> + * This program is free software; you can redistribute it and/or modify
> >> + * it under the terms of the GNU General Public License as published by
> >> + * the Free Software Foundation; either version 2 of the License, or
> >> + * (at your option) any later version.
> > 
> > I have to ask, do you really mean, "or any later version”?
> > 
> 
> Yes, this is purely a community thing. No evil vendor at play at all.

I have no idea what that means.


> >> + *
> >> + * This program is distributed in the hope that it will be useful,
> >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> >> + * GNU General Public License for more details.
> >> + */
> >> +
> >> +#include <linux/module.h>
> >> +#include <linux/delay.h>
> >> +#include <linux/err.h>
> >> +#include <linux/interrupt.h>
> >> +#include <linux/completion.h>
> >> +#include <linux/platform_device.h>
> >> +#include <linux/clk.h>
> >> +#include <linux/io.h>
> >> +#include <linux/of.h>
> >> +#include <linux/of_device.h>
> >> +#include <linux/of_fdt.h>
> >> +#include <linux/slab.h>
> >> +#include <linux/pm_runtime.h>
> >> +#include <linux/pinctrl/consumer.h>
> >> +#include <linux/firmware.h>
> >> +#include <linux/err.h>
> >> +#include <linux/ctype.h>
> >> +#include <linux/string.h>
> >> +#include <linux/memory.h>
> >> +#include <linux/kthread.h>
> >> +#include <linux/wait.h>
> >> +#include <linux/file.h>
> >> +#include <linux/fs.h>
> >> +#include <linux/eeprom-consumer.h>
> >> +
> >> +/* disabled capes */
> >> +static char *disable_partno;
> >> +module_param(disable_partno, charp, 0444);
> >> +MODULE_PARM_DESC(disable_partno,
> >> +		"Comma delimited list of PART-NUMBER[:REV] of disabled capes");
> >> +
> >> +/* enable capes */
> >> +static char *enable_partno;
> >> +module_param(enable_partno, charp, 0444);
> >> +MODULE_PARM_DESC(enable_partno,
> >> +		"Comma delimited list of PART-NUMBER[:REV] of enabled capes");
> >> +
> >> +/* delay to scan on boot until rootfs appears */
> >> +static int boot_scan_period = 1000;
> >> +module_param(boot_scan_period, int, 0444);
> >> +MODULE_PARM_DESC(boot_scan_period,
> >> +		"boot scan period until rootfs firmware is available");
> > 
> > Ick, no module parameters please, can't we drop these?
> > 
> 
> In a nutshell, no :)
> 
> These has to be way to control whether a cape is disabled (if found) and enabled (if the manufacturer in it’s infinite wisdom removed the EEPROM to save $0.01 per cape).

Please line-wrap your responses.

> The easiest way to achieve this is with the kernel command line.

No it is not.  You can't easily change the kernel command line for an
embedded system (or so everyone keeps telling me when I say things like
"just update your kernel command line!")  So embedded people can't have
it both ways, sorry.

Can't you put these in a dt file?

> > And we have a rootfs delay option already for the whole system, this
> > module shouldn't need a special one.
> > 
> 
> No, that won’t work.
> 
> You see the problem is as follows.
> 
> The capemanager is not built as a module, it is builtin.

Not according to your Kconfig file :)

> By the time the probe method is called the rootfs has no been mounted yet.
> This is actually what we want for the cases where the rootfs resides on a cape and
> the cape’s dtbo firmware file is built-in the kernel image.
> 
> This does not work when the firmware file is located in the rootfs filesystem, since
> the call to request_firmware will fail at that time.

Then you let it happen later.  Or do it async.  Don't create new command
line options for when we already have the same command line option!

> That option controls the polling delay until the system boot state indicates that the
> rootfs is available and the call will succeed.

If this is such an issue, just sit and spin and wait for it to show up.

> There are lots of warts in our firmware loader.

You can fix them, don't make the kernel work around the warts because
you don't want to :)

thanks,

greg k-h

Re: [PATCH 1/5] misc: Beaglebone capemanager

[Pantelis Antoniou]

Hi Greg,

> On May 13, 2015, at 18:36 , Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> 
> On Wed, May 13, 2015 at 03:10:25PM +0300, Pantelis Antoniou wrote:
>> Hi Greg,
>> 
>>> On May 13, 2015, at 14:55 , Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
>>> 
>>> On Wed, May 13, 2015 at 10:59:41AM +0300, Pantelis Antoniou wrote:
>>>> A cape loader based on DT overlays and DT objects.
>>>> 
>>>> This is the beaglebone cape manager which allows capes to be automatically
>>>> probed and instantiated via means of a device tree overlay deduced from
>>>> the part-number and version contained on the cape's EEPROM.
>>>> 
>>>> The reference manual contains information about the specification
>>>> and the contents of the EEPROM.
>>>> 
>>>> http://beagleboard.org/static/beaglebone/latest/Docs/Hardware/BONE_SRM.pdf
>>>> 
>>>> Documentation about the workings of the cape manager is located
>>>> in Documentation/misc-devices/bone_capemgr.txt
>>>> 
>>>> This driver is using the EEPROM framework interface to retrieve
>>>> the data stored on the baseboard and cape EEPROMs.
>>>> 
>>>> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
>>>> ---
>>>> drivers/misc/Kconfig        |   10 +
>>>> drivers/misc/Makefile       |    1 +
>>>> drivers/misc/bone_capemgr.c | 1926 +++++++++++++++++++++++++++++++++++++++++++
>>>> 3 files changed, 1937 insertions(+)
>>>> create mode 100644 drivers/misc/bone_capemgr.c
>>>> 
>>>> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
>>>> index 006242c..f9e09e1 100644
>>>> --- a/drivers/misc/Kconfig
>>>> +++ b/drivers/misc/Kconfig
>>>> @@ -515,6 +515,16 @@ config VEXPRESS_SYSCFG
>>>> 	  bus. System Configuration interface is one of the possible means
>>>> 	  of generating transactions on this bus.
>>>> 
>>>> +config BONE_CAPEMGR
>>>> +	tristate "Beaglebone cape manager"
>>>> +	depends on ARCH_OMAP2PLUS && OF
>>>> +	select EEPROM
>>>> +	select OF_OVERLAY
>>>> +	default n
>>> 
>>> N is always the default, please remove.
>>> 
>> 
>> OK
>> 
>>>> +	help
>>>> +	  Say Y here to include support for automatic loading of
>>>> +	  beaglebone capes.
>>>> +
>>> 
>>> What about if it's a module?
>>> 
>>> 
>> 
>> It should work but it’s going to be weird (i.e. no-one has used it as such).
>> I’ll update the blurb.
> 
> You are saying it is a valid config option, so please test it as such,
> or if it's not a valid config option, don't allow it.
> 

It is a valid option, just no-one has a use for it. Who knows what kind of
crazy setup the end-users will use.

I’ll test it as a module to make sure.

>>>> source "drivers/misc/c2port/Kconfig"
>>>> source "drivers/misc/eeprom/Kconfig"
>>>> source "drivers/misc/cb710/Kconfig"
>>>> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
>>>> index 7d5c4cd..659b78b 100644
>>>> --- a/drivers/misc/Makefile
>>>> +++ b/drivers/misc/Makefile
>>>> @@ -56,3 +56,4 @@ obj-$(CONFIG_GENWQE)		+= genwqe/
>>>> obj-$(CONFIG_ECHO)		+= echo/
>>>> obj-$(CONFIG_VEXPRESS_SYSCFG)	+= vexpress-syscfg.o
>>>> obj-$(CONFIG_CXL_BASE)		+= cxl/
>>>> +obj-$(CONFIG_BONE_CAPEMGR)	+= bone_capemgr.o
>>>> diff --git a/drivers/misc/bone_capemgr.c b/drivers/misc/bone_capemgr.c
>>>> new file mode 100644
>>>> index 0000000..423719c
>>>> --- /dev/null
>>>> +++ b/drivers/misc/bone_capemgr.c
>>>> @@ -0,0 +1,1926 @@
>>>> +/*
>>>> + * TI Beaglebone cape manager
>>>> + *
>>>> + * Copyright (C) 2012 Texas Instruments Inc.
>>>> + * Copyright (C) 2012-2015 Konsulko Group.
>>>> + * Author: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
>>>> + *
>>>> + * This program is free software; you can redistribute it and/or modify
>>>> + * it under the terms of the GNU General Public License as published by
>>>> + * the Free Software Foundation; either version 2 of the License, or
>>>> + * (at your option) any later version.
>>> 
>>> I have to ask, do you really mean, "or any later version”?
>>> 
>> 
>> Yes, this is purely a community thing. No evil vendor at play at all.
> 
> I have no idea what that means.
> 
> 

That this is purely work for the community. No-one pays for it.

>>>> + *
>>>> + * This program is distributed in the hope that it will be useful,
>>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>>>> + * GNU General Public License for more details.
>>>> + */
>>>> +
>>>> +#include <linux/module.h>
>>>> +#include <linux/delay.h>
>>>> +#include <linux/err.h>
>>>> +#include <linux/interrupt.h>
>>>> +#include <linux/completion.h>
>>>> +#include <linux/platform_device.h>
>>>> +#include <linux/clk.h>
>>>> +#include <linux/io.h>
>>>> +#include <linux/of.h>
>>>> +#include <linux/of_device.h>
>>>> +#include <linux/of_fdt.h>
>>>> +#include <linux/slab.h>
>>>> +#include <linux/pm_runtime.h>
>>>> +#include <linux/pinctrl/consumer.h>
>>>> +#include <linux/firmware.h>
>>>> +#include <linux/err.h>
>>>> +#include <linux/ctype.h>
>>>> +#include <linux/string.h>
>>>> +#include <linux/memory.h>
>>>> +#include <linux/kthread.h>
>>>> +#include <linux/wait.h>
>>>> +#include <linux/file.h>
>>>> +#include <linux/fs.h>
>>>> +#include <linux/eeprom-consumer.h>
>>>> +
>>>> +/* disabled capes */
>>>> +static char *disable_partno;
>>>> +module_param(disable_partno, charp, 0444);
>>>> +MODULE_PARM_DESC(disable_partno,
>>>> +		"Comma delimited list of PART-NUMBER[:REV] of disabled capes");
>>>> +
>>>> +/* enable capes */
>>>> +static char *enable_partno;
>>>> +module_param(enable_partno, charp, 0444);
>>>> +MODULE_PARM_DESC(enable_partno,
>>>> +		"Comma delimited list of PART-NUMBER[:REV] of enabled capes");
>>>> +
>>>> +/* delay to scan on boot until rootfs appears */
>>>> +static int boot_scan_period = 1000;
>>>> +module_param(boot_scan_period, int, 0444);
>>>> +MODULE_PARM_DESC(boot_scan_period,
>>>> +		"boot scan period until rootfs firmware is available");
>>> 
>>> Ick, no module parameters please, can't we drop these?
>>> 
>> 
>> In a nutshell, no :)
>> 
>> These has to be way to control whether a cape is disabled (if found) and enabled (if the manufacturer in it’s infinite wisdom removed the EEPROM to save $0.01 per cape).
> 
> Please line-wrap your responses.
> 
>> The easiest way to achieve this is with the kernel command line.
> 
> No it is not.  You can't easily change the kernel command line for an
> embedded system (or so everyone keeps telling me when I say things like
> "just update your kernel command line!")  So embedded people can't have
> it both ways, sorry.
> 

Depends on the embedded system. On the ones I’m working with a sane bootloader
(for example u-boot) the command line is easily modified.

> Can't you put these in a dt file?
> 

Do you really want to start this argument? Didn’t we used to have great flamewars
about putting linux specific things in the DT?

Does enabling & disabling capes fall into ‘hardware description’?

I guess we’ll have to ask the DT maintainers for that.

Rob, Grant? 

>>> And we have a rootfs delay option already for the whole system, this
>>> module shouldn't need a special one.
>>> 
>> 
>> No, that won’t work.
>> 
>> You see the problem is as follows.
>> 
>> The capemanager is not built as a module, it is builtin.
> 
> Not according to your Kconfig file :)
> 

Touché

>> By the time the probe method is called the rootfs has no been mounted yet.
>> This is actually what we want for the cases where the rootfs resides on a cape and
>> the cape’s dtbo firmware file is built-in the kernel image.
>> 
>> This does not work when the firmware file is located in the rootfs filesystem, since
>> the call to request_firmware will fail at that time.
> 
> Then you let it happen later.  Or do it async.  Don't create new command
> line options for when we already have the same command line option!
> 

Err, the two options are nothing alike no? One deals is defined as:

rootdelay: "Delay (in seconds) to pause before attempting to mount the root filesystem"

The other is the period with which to perform period firmware requests.

>> That option controls the polling delay until the system boot state indicates that the
>> rootfs is available and the call will succeed.
> 
> If this is such an issue, just sit and spin and wait for it to show up.
> 

I can do that; that would get rid of the option too.

>> There are lots of warts in our firmware loader.
> 
> You can fix them, don't make the kernel work around the warts because
> you don't want to :)
> 

Yes, but that’s not the case here. I have in mind fixing some problems with the
firmware loader, but http://www.imdb.com/title/tt0070355/quotes?item=qt1629888


> thanks,
> 
> greg k-h


Regards

— Pantelis

Re: [PATCH 1/5] misc: Beaglebone capemanager

[Geert Uytterhoeven]

On Wed, May 13, 2015 at 9:59 AM, Pantelis Antoniou
<pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org> wrote:
> diff --git a/drivers/misc/bone_capemgr.c b/drivers/misc/bone_capemgr.c
> new file mode 100644
> index 0000000..423719c
> --- /dev/null
> +++ b/drivers/misc/bone_capemgr.c

> +static int capemgr_load_slot(struct bone_cape_slot *slot)
> +{

[...]

> +       of_fdt_unflatten_tree((void *)slot->fw->data, &slot->overlay);

After "[PATCH] of/fdt: Make fdt blob input parameters of unflatten functions
const", you can remove the cast.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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[PATCH 2/5] doc: misc: Beaglebone capemanager documentation

[Pantelis Antoniou]

Add beaglebone capemanager documentation entry.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
---
 Documentation/misc-devices/bone_capemgr.txt | 63 +++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 Documentation/misc-devices/bone_capemgr.txt

diff --git a/Documentation/misc-devices/bone_capemgr.txt b/Documentation/misc-devices/bone_capemgr.txt
new file mode 100644
index 0000000..2a8c766
--- /dev/null
+++ b/Documentation/misc-devices/bone_capemgr.txt
@@ -0,0 +1,63 @@
+---------------------------
+  Beaglebone Cape-Manager
+---------------------------
+
+The beaglebone cape manager driver allows the automatic use of external
+peripheral capes to be automatically supported by Linux without any manual
+setup required by the user.
+
+Each beaglebone cape should contain an EEPROM that describes
+it in a fixed I2C address on the i2c2 bus of the baseboard.
+The format of the EEPROM is defined in the beaglebone reference
+manual at:
+http://beagleboard.org/static/beaglebone/latest/Docs/Hardware/BONE_SRM.pdf
+
+Reading the part number and revision information the manager
+requests a firmware file formatted as a device tree overlay blob.
+
+Applying the overlay the devices are instantiated and the cape is
+ready to be used.
+
+For instance if the part-number is BB-BONE-SERL-03 and the version is 00A1
+the firmware file requested will be BB-BONE-SERL-03-00A1-00A1.dtbo
+It will be located by the in-kernel firmware
+loader in the usual place, i.e.  /lib/firmware/`uname -r`, /lib/firmware etc.
+
+The driver supports the following parameters (either as part of the kernel
+command line or supplied at module insertion time).
+
+disable_partno:   A comma delimited list of PART-NUMBER[:REV] of
+                  disabled capes.
+enable_partno:    A comma delimited list of PART-NUMBER[:REV[:PRIO]] of
+                  enabled capes.
+boot_scan_period: The boot scan period in ms. When the cape manager is built-in
+                  the kernel image, the firmware loader cannot find the files
+		  before the rootfs is mounted. This parameter controls the
+		  period with which the boot state is checked in that case.
+
+There's a sysfs control interface which is defined at the ABI documentation
+area.
+
+Theory of operation:
+--------------------
+
+On driver probe the I2C EEPROM of the baseboard is read and information about
+the current baseboard is retrieved. This information includes the mapping from
+baseboard board name to DT friendly compatible string. I.e. the "A335BONE" board
+name from EEPROM is mapped to the "ti,beaglebone" compatible string which should
+be present in the dtbo to be loaded.
+
+Afterwards the EEPROMs declared in each slot are probed, and the EEPROMs found
+are decoded keeping track the cape part-number and version data.
+
+Using the part-number and version a firmware file is requested (the firmware
+file requested is <part-number>-<version>.dtbo).
+
+The dtbo is unflattend and the resulting device tree is matched against a
+compatible baseboard, and in case of multiple parallel loading capes the
+priorities defined are honored.  That means that when there are multiple capes
+being loaded in parallel the ones with the lowest priority number are loaded
+first.
+
+Applying the device tree overlay makes the cape operational, as if it was part
+of the kernel's booting device tree.
-- 
1.7.12

[PATCH 3/5] doc: dt: beaglebone cape manager bindings.

[Pantelis Antoniou]

Bindings document for the beaglebone cape manager.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
---
 .../devicetree/bindings/misc/bone_capemgr.txt      | 123 +++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/misc/bone_capemgr.txt

diff --git a/Documentation/devicetree/bindings/misc/bone_capemgr.txt b/Documentation/devicetree/bindings/misc/bone_capemgr.txt
new file mode 100644
index 0000000..006f50c
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/bone_capemgr.txt
@@ -0,0 +1,123 @@
+* Beaglebone cape manager driver
+
+Required properties:
+- compatible: "ti,bone-capemgr"
+- eeprom: phandle to the EEPROM baseboard.
+          The EEPROM framework interface is use to obtain the data.
+
+Required children nodes:
+
+- baseboardmaps: Contains nodes, which each of the them defines a mapping from
+		 the baseboard EEPROM board-name ID to a DT friendly compatible
+		 string.
+
+  - board-name:      The baseboard EEPROM board name, i.e. A335BONE for the original
+		     beaglebone white.
+  - compatible-name: The DT friendly compatible string to be used for matching
+		     compatible capes, i.e. "ti,beaglebone"
+
+
+ - slots: Defines the slots (I2C addresses) that capes are available.
+  - eeprom: phandle to the EEPROM cape.
+            The EEPROM framework interface is used to obtain the data.
+
+- Example of a beaglebone cape-manager:
+
+bone_capemgr {
+	compatible = "ti,bone-capemgr";
+	status = "okay";
+
+	eeprom = <&baseboard_eeprom>;
+
+	/* map board revisions to compatible definitions */
+	baseboardmaps {
+		baseboard_beaglebone: board@0 {
+			board-name = "A335BONE";
+			compatible-name = "ti,beaglebone";
+		};
+
+		baseboard_beaglebone_black: board@1 {
+			board-name = "A335BNLT";
+			compatible-name = "ti,beaglebone-black";
+		};
+	};
+
+	/* only 4 slots defined */
+	slots {
+		slot@0 {
+			eeprom = <&cape_eeprom0>;
+		};
+
+		slot@1 {
+			eeprom = <&cape_eeprom1>;
+		};
+
+		slot@2 {
+			eeprom = <&cape_eeprom2>;
+		};
+
+		slot@3 {
+			eeprom = <&cape_eeprom3>;
+		};
+	};
+};
+
+The format of the cape to be loaded is in a standard overlay format with
+the following root properties that are interpreted by the cape manager:
+
+Required properties:
+ - compatible: Should be compatible to the baseboard according to the
+               baseboard map value, i.e. "ti,beaglebone".
+ - part-numer: Should contain the part-number as stored in the EEPROM.
+ - version:    Should contain a list of all the version that are supported
+               by the single cape dtbo, i.e. "00A1".
+
+Optional properties:
+ - exclusive-use: A string list which state the resources this cape requires.
+                  No processing or matching to anything regarding the internal
+		  kernel state is performed; it's purpose is to guard against
+		  conflicts with other capes.
+ - priority:      A priority to be assigned when loading a cape. A lower value
+                  has higher priority. The purpose of the priority is to control
+		  which cape is loaded first in case of a conflict.
+
+- Example of a serial cape:
+
+/dts-v1/;
+/plugin/;
+/ {
+        compatible = "ti,beaglebone", "ti,beaglebone-black";
+
+        /* identification */
+        part-number = "BB-BONE-SERL-03";
+        version = "00A1";
+
+        /* state the resources this cape uses */
+        exclusive-use =
+                /* the pin header uses */
+                "P9.21",        /* uart2_txd */
+                "P9.22",        /* uart2_rxd */
+                /* the hardware ip uses */
+                "uart2";
+
+        fragment@0 {
+                target = <&am33xx_pinmux>;
+                __overlay__ {
+                        bb_uart2_pins: pinmux_bb_uart2_pins {
+                                pinctrl-single,pins = <
+                                        0x150 0x21      /* spi0_sclk.uart2_rxd | MODE1 */
+                                        0x154 0x01      /* spi0_d0.uart2_txd | MODE1 */
+                                >;
+                        };
+                };
+        };
+
+        fragment@1 {
+                target = <&uart2>;
+                __overlay__ {
+                        status = "okay";
+                        pinctrl-names = "default";
+                        pinctrl-0 = <&bb_uart2_pins>;
+                };
+        };
+};
-- 
1.7.12

[PATCH 4/5] doc: ABI: bone_capemgr sysfs API

[Pantelis Antoniou]

Document the beaglebone's capemgr sysfs API

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
---
 .../testing/sysfs-devices-platform-bone_capemgr    | 63 ++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr

diff --git a/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr b/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
new file mode 100644
index 0000000..e2df613
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
@@ -0,0 +1,63 @@
+What:		/sys/devices/platform/bone_capemgr/slots
+Date:		May 2015
+KernelVersion:	4.0
+Contact:	Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+Description:
+		READ:
+		  Describe the state of all the slots of the beaglebone capemgr.
+		  Each line of the output describes a slot:
+		  The slot format is as following:
+		  <slot-id>: [P-][F-][O-][l-][L-][D-] \
+			  <overlay-id> <board-name>,<version>,
+			  <manufacturer>,<part-number>
+
+		Where the flags are:
+		P: Slot has been probed
+		F: Slot has failed probing (i.e. no EEPROM detected)
+		O: Slot has been overridden by the user
+		l: Slot is current loading
+		L: Slot has completed loading and is ready
+		D: Slot has been disabled
+
+		Example:
+		0: P---L-  -1 BeagleBone RS232 CAPE,00A1,Beagleboardtoys,BB-BONE-SERL-03
+		1: PF----  -1
+		2: PF----  -1
+		3: PF----  -1
+
+		WRITE:
+		  Writing a string of the form <part-number>[:version] issues a request to
+		  load a firmware blob containing an overlay. The name of the firmware blob
+		  is <part-number>-[version|00A0].dtbo. This act is defined as a slot override.
+
+		  Writing a negative slot id removes the slot if it was an overridden one, or
+		  unloads a slot that was probed.
+
+What:		/sys/devices/platform/bone_capemgr/baseboard/<eeprom-field>
+Date:		May 2015
+KernelVersion:	4.0
+Contact:	Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+Description:	Contains the probed base board EEPROM field; one of:
+		board-name		- board-name as stored in cape EEPROM
+		dc-supplied		- whether the cape draws or supplies DC
+		eeprom-format-revision	- EEPROM format rev, only 00A0 supported
+		header			- header; should be 'aa 55 33 ee'
+		manufacturer		- manufacturer string
+		part-number		- part-number of the cape
+		serial-number		- serial number of the cape
+		version			- version of the cape, i.e. 00A0
+		number-of-pins		- displayed but ignored
+		pin-usage		- displayed but ignored
+		sys-5v			- displayed but ignored
+		vdd-3v3exp		- displayed but ignored
+		vdd-5v			- displayed but ignored
+What:		/sys/devices/platform/bone_capemgr/slot-<n>/<eeprom-field>
+Date:		May 2015
+KernelVersion:	4.0
+Contact:	Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+Description:	Contains the probed cape's EEPROM field; the field is one of:
+		board-name		- baseboard name i.e. A335BNLT
+		header			- header; should be 'aa 55 33 ee'
+		revision		- baseboard revision
+		serial-number		- baseboard serial number
+		config-option		- displayed but ignored
-- 
1.7.12

Re: [PATCH 4/5] doc: ABI: bone_capemgr sysfs API

[Greg Kroah-Hartman]

On Wed, May 13, 2015 at 10:59:44AM +0300, Pantelis Antoniou wrote:
> Document the beaglebone's capemgr sysfs API
> 
> Signed-off-by: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
> ---
>  .../testing/sysfs-devices-platform-bone_capemgr    | 63 ++++++++++++++++++++++
>  1 file changed, 63 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
> 
> diff --git a/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr b/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
> new file mode 100644
> index 0000000..e2df613
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
> @@ -0,0 +1,63 @@
> +What:		/sys/devices/platform/bone_capemgr/slots
> +Date:		May 2015
> +KernelVersion:	4.0

I don't think that version is correct :)

> +Contact:	Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
> +Description:
> +		READ:
> +		  Describe the state of all the slots of the beaglebone capemgr.
> +		  Each line of the output describes a slot:

sysfs files are "one value per file", so a sysfs file that displays
multiple lines like this is not allowed at all, sorry.

Please either make it a debugfs file (if this is only for debugging, or
split it out into individual files, one per slot (hint, one per slot is
probably best.)

> +		  The slot format is as following:
> +		  <slot-id>: [P-][F-][O-][l-][L-][D-] \
> +			  <overlay-id> <board-name>,<version>,
> +			  <manufacturer>,<part-number>
> +
> +		Where the flags are:
> +		P: Slot has been probed
> +		F: Slot has failed probing (i.e. no EEPROM detected)
> +		O: Slot has been overridden by the user
> +		l: Slot is current loading
> +		L: Slot has completed loading and is ready
> +		D: Slot has been disabled
> +
> +		Example:
> +		0: P---L-  -1 BeagleBone RS232 CAPE,00A1,Beagleboardtoys,BB-BONE-SERL-03
> +		1: PF----  -1
> +		2: PF----  -1
> +		3: PF----  -1
> +
> +		WRITE:
> +		  Writing a string of the form <part-number>[:version] issues a request to
> +		  load a firmware blob containing an overlay. The name of the firmware blob
> +		  is <part-number>-[version|00A0].dtbo. This act is defined as a slot override.
> +
> +		  Writing a negative slot id removes the slot if it was an overridden one, or
> +		  unloads a slot that was probed.
> +
> +What:		/sys/devices/platform/bone_capemgr/baseboard/<eeprom-field>
> +Date:		May 2015
> +KernelVersion:	4.0
> +Contact:	Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
> +Description:	Contains the probed base board EEPROM field; one of:
> +		board-name		- board-name as stored in cape EEPROM
> +		dc-supplied		- whether the cape draws or supplies DC
> +		eeprom-format-revision	- EEPROM format rev, only 00A0 supported
> +		header			- header; should be 'aa 55 33 ee'

If it's always this value, why have the file?

> +		manufacturer		- manufacturer string
> +		part-number		- part-number of the cape
> +		serial-number		- serial number of the cape
> +		version			- version of the cape, i.e. 00A0
> +		number-of-pins		- displayed but ignored
> +		pin-usage		- displayed but ignored
> +		sys-5v			- displayed but ignored
> +		vdd-3v3exp		- displayed but ignored
> +		vdd-5v			- displayed but ignored

Are these all individual different files?

> +What:		/sys/devices/platform/bone_capemgr/slot-<n>/<eeprom-field>

No blank line?

> +Date:		May 2015
> +KernelVersion:	4.0
> +Contact:	Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
> +Description:	Contains the probed cape's EEPROM field; the field is one of:
> +		board-name		- baseboard name i.e. A335BNLT
> +		header			- header; should be 'aa 55 33 ee'
> +		revision		- baseboard revision
> +		serial-number		- baseboard serial number
> +		config-option		- displayed but ignored

Same here, are these all individual files?

thanks,

greg k-h

Re: [PATCH 4/5] doc: ABI: bone_capemgr sysfs API

[Pantelis Antoniou]

Hi Greg,

> On May 13, 2015, at 14:52 , Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> 
> On Wed, May 13, 2015 at 10:59:44AM +0300, Pantelis Antoniou wrote:
>> Document the beaglebone's capemgr sysfs API
>> 
>> Signed-off-by: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
>> ---
>> .../testing/sysfs-devices-platform-bone_capemgr    | 63 ++++++++++++++++++++++
>> 1 file changed, 63 insertions(+)
>> create mode 100644 Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
>> 
>> diff --git a/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr b/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
>> new file mode 100644
>> index 0000000..e2df613
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
>> @@ -0,0 +1,63 @@
>> +What:		/sys/devices/platform/bone_capemgr/slots
>> +Date:		May 2015
>> +KernelVersion:	4.0
> 
> I don't think that version is correct :)
> 

Bah, ++

>> +Contact:	Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
>> +Description:
>> +		READ:
>> +		  Describe the state of all the slots of the beaglebone capemgr.
>> +		  Each line of the output describes a slot:
> 
> sysfs files are "one value per file", so a sysfs file that displays
> multiple lines like this is not allowed at all, sorry.
> 
> Please either make it a debugfs file (if this is only for debugging, or
> split it out into individual files, one per slot (hint, one per slot is
> probably best.)
> 

Well, it’s a status file. And it’s been used as is for a couple of years
so it was worth a shot for backward compatibility.


>> +		  The slot format is as following:
>> +		  <slot-id>: [P-][F-][O-][l-][L-][D-] \
>> +			  <overlay-id> <board-name>,<version>,
>> +			  <manufacturer>,<part-number>
>> +
>> +		Where the flags are:
>> +		P: Slot has been probed
>> +		F: Slot has failed probing (i.e. no EEPROM detected)
>> +		O: Slot has been overridden by the user
>> +		l: Slot is current loading
>> +		L: Slot has completed loading and is ready
>> +		D: Slot has been disabled
>> +
>> +		Example:
>> +		0: P---L-  -1 BeagleBone RS232 CAPE,00A1,Beagleboardtoys,BB-BONE-SERL-03
>> +		1: PF----  -1
>> +		2: PF----  -1
>> +		3: PF----  -1
>> +
>> +		WRITE:
>> +		  Writing a string of the form <part-number>[:version] issues a request to
>> +		  load a firmware blob containing an overlay. The name of the firmware blob
>> +		  is <part-number>-[version|00A0].dtbo. This act is defined as a slot override.
>> +
>> +		  Writing a negative slot id removes the slot if it was an overridden one, or
>> +		  unloads a slot that was probed.
>> +
>> +What:		/sys/devices/platform/bone_capemgr/baseboard/<eeprom-field>
>> +Date:		May 2015
>> +KernelVersion:	4.0
>> +Contact:	Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
>> +Description:	Contains the probed base board EEPROM field; one of:
>> +		board-name		- board-name as stored in cape EEPROM
>> +		dc-supplied		- whether the cape draws or supplies DC
>> +		eeprom-format-revision	- EEPROM format rev, only 00A0 supported
>> +		header			- header; should be 'aa 55 33 ee'
> 
> If it's always this value, why have the file?
> 

These are the contents of the EEPROM. If the format of the EEPROM changes then the
header information will change.

>> +		manufacturer		- manufacturer string
>> +		part-number		- part-number of the cape
>> +		serial-number		- serial number of the cape
>> +		version			- version of the cape, i.e. 00A0
>> +		number-of-pins		- displayed but ignored
>> +		pin-usage		- displayed but ignored
>> +		sys-5v			- displayed but ignored
>> +		vdd-3v3exp		- displayed but ignored
>> +		vdd-5v			- displayed but ignored
> 
> Are these all individual different files?
> 

Yes

>> +What:		/sys/devices/platform/bone_capemgr/slot-<n>/<eeprom-field>
> 
> No blank line?
> 

OK

>> +Date:		May 2015
>> +KernelVersion:	4.0
>> +Contact:	Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
>> +Description:	Contains the probed cape's EEPROM field; the field is one of:
>> +		board-name		- baseboard name i.e. A335BNLT
>> +		header			- header; should be 'aa 55 33 ee'
>> +		revision		- baseboard revision
>> +		serial-number		- baseboard serial number
>> +		config-option		- displayed but ignored
> 
> Same here, are these all individual files?
> 

Yes.

> thanks,
> 
> greg k-h

Regards

— Pantelis

Re: [PATCH 4/5] doc: ABI: bone_capemgr sysfs API

[Greg Kroah-Hartman]

On Wed, May 13, 2015 at 02:56:49PM +0300, Pantelis Antoniou wrote:
> Hi Greg,
> 
> > On May 13, 2015, at 14:52 , Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> > 
> > On Wed, May 13, 2015 at 10:59:44AM +0300, Pantelis Antoniou wrote:
> >> Document the beaglebone's capemgr sysfs API
> >> 
> >> Signed-off-by: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
> >> ---
> >> .../testing/sysfs-devices-platform-bone_capemgr    | 63 ++++++++++++++++++++++
> >> 1 file changed, 63 insertions(+)
> >> create mode 100644 Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
> >> 
> >> diff --git a/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr b/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
> >> new file mode 100644
> >> index 0000000..e2df613
> >> --- /dev/null
> >> +++ b/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
> >> @@ -0,0 +1,63 @@
> >> +What:		/sys/devices/platform/bone_capemgr/slots
> >> +Date:		May 2015
> >> +KernelVersion:	4.0
> > 
> > I don't think that version is correct :)
> > 
> 
> Bah, ++
> 
> >> +Contact:	Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
> >> +Description:
> >> +		READ:
> >> +		  Describe the state of all the slots of the beaglebone capemgr.
> >> +		  Each line of the output describes a slot:
> > 
> > sysfs files are "one value per file", so a sysfs file that displays
> > multiple lines like this is not allowed at all, sorry.
> > 
> > Please either make it a debugfs file (if this is only for debugging, or
> > split it out into individual files, one per slot (hint, one per slot is
> > probably best.)
> > 
> 
> Well, it’s a status file. And it’s been used as is for a couple of years
> so it was worth a shot for backward compatibility.

There is not "backwards compatiblity" for when you do things wrong in
the first place, you can't claim that here, sorry.

And don't "try" to introduce things you know is wrong, that just makes
maintainers _very_ suspicious of everything else you are doing here...

> >> +		  The slot format is as following:
> >> +		  <slot-id>: [P-][F-][O-][l-][L-][D-] \
> >> +			  <overlay-id> <board-name>,<version>,
> >> +			  <manufacturer>,<part-number>
> >> +
> >> +		Where the flags are:
> >> +		P: Slot has been probed
> >> +		F: Slot has failed probing (i.e. no EEPROM detected)
> >> +		O: Slot has been overridden by the user
> >> +		l: Slot is current loading
> >> +		L: Slot has completed loading and is ready
> >> +		D: Slot has been disabled
> >> +
> >> +		Example:
> >> +		0: P---L-  -1 BeagleBone RS232 CAPE,00A1,Beagleboardtoys,BB-BONE-SERL-03
> >> +		1: PF----  -1
> >> +		2: PF----  -1
> >> +		3: PF----  -1
> >> +
> >> +		WRITE:
> >> +		  Writing a string of the form <part-number>[:version] issues a request to
> >> +		  load a firmware blob containing an overlay. The name of the firmware blob
> >> +		  is <part-number>-[version|00A0].dtbo. This act is defined as a slot override.
> >> +
> >> +		  Writing a negative slot id removes the slot if it was an overridden one, or
> >> +		  unloads a slot that was probed.
> >> +
> >> +What:		/sys/devices/platform/bone_capemgr/baseboard/<eeprom-field>
> >> +Date:		May 2015
> >> +KernelVersion:	4.0
> >> +Contact:	Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
> >> +Description:	Contains the probed base board EEPROM field; one of:
> >> +		board-name		- board-name as stored in cape EEPROM
> >> +		dc-supplied		- whether the cape draws or supplies DC
> >> +		eeprom-format-revision	- EEPROM format rev, only 00A0 supported
> >> +		header			- header; should be 'aa 55 33 ee'
> > 
> > If it's always this value, why have the file?
> > 
> 
> These are the contents of the EEPROM. If the format of the EEPROM changes then the
> header information will change.

Then don't say "should be", because what happens in the future if it is
not.

> >> +		manufacturer		- manufacturer string
> >> +		part-number		- part-number of the cape
> >> +		serial-number		- serial number of the cape
> >> +		version			- version of the cape, i.e. 00A0
> >> +		number-of-pins		- displayed but ignored
> >> +		pin-usage		- displayed but ignored
> >> +		sys-5v			- displayed but ignored
> >> +		vdd-3v3exp		- displayed but ignored
> >> +		vdd-5v			- displayed but ignored
> > 
> > Are these all individual different files?
> > 
> 
> Yes

Then write out the individual files please as different entries.

Also, the "displayed but ignored" doesn't make sense, please fix that
up.

greg k-h

Re: [PATCH 4/5] doc: ABI: bone_capemgr sysfs API

[Pantelis Antoniou]

Hi Greg,

> On May 13, 2015, at 15:08 , Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> 
> On Wed, May 13, 2015 at 02:56:49PM +0300, Pantelis Antoniou wrote:
>> Hi Greg,
>> 
>>> On May 13, 2015, at 14:52 , Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
>>> 
>>> On Wed, May 13, 2015 at 10:59:44AM +0300, Pantelis Antoniou wrote:
>>>> Document the beaglebone's capemgr sysfs API
>>>> 
>>>> Signed-off-by: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
>>>> ---
>>>> .../testing/sysfs-devices-platform-bone_capemgr    | 63 ++++++++++++++++++++++
>>>> 1 file changed, 63 insertions(+)
>>>> create mode 100644 Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
>>>> 
>>>> diff --git a/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr b/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
>>>> new file mode 100644
>>>> index 0000000..e2df613
>>>> --- /dev/null
>>>> +++ b/Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
>>>> @@ -0,0 +1,63 @@
>>>> +What:		/sys/devices/platform/bone_capemgr/slots
>>>> +Date:		May 2015
>>>> +KernelVersion:	4.0
>>> 
>>> I don't think that version is correct :)
>>> 
>> 
>> Bah, ++
>> 
>>>> +Contact:	Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
>>>> +Description:
>>>> +		READ:
>>>> +		  Describe the state of all the slots of the beaglebone capemgr.
>>>> +		  Each line of the output describes a slot:
>>> 
>>> sysfs files are "one value per file", so a sysfs file that displays
>>> multiple lines like this is not allowed at all, sorry.
>>> 
>>> Please either make it a debugfs file (if this is only for debugging, or
>>> split it out into individual files, one per slot (hint, one per slot is
>>> probably best.)
>>> 
>> 
>> Well, it’s a status file. And it’s been used as is for a couple of years
>> so it was worth a shot for backward compatibility.
> 
> There is not "backwards compatiblity" for when you do things wrong in
> the first place, you can't claim that here, sorry.
> 
> And don't "try" to introduce things you know is wrong, that just makes
> maintainers _very_ suspicious of everything else you are doing here…
> 

OK

>>>> +		  The slot format is as following:
>>>> +		  <slot-id>: [P-][F-][O-][l-][L-][D-] \
>>>> +			  <overlay-id> <board-name>,<version>,
>>>> +			  <manufacturer>,<part-number>
>>>> +
>>>> +		Where the flags are:
>>>> +		P: Slot has been probed
>>>> +		F: Slot has failed probing (i.e. no EEPROM detected)
>>>> +		O: Slot has been overridden by the user
>>>> +		l: Slot is current loading
>>>> +		L: Slot has completed loading and is ready
>>>> +		D: Slot has been disabled
>>>> +
>>>> +		Example:
>>>> +		0: P---L-  -1 BeagleBone RS232 CAPE,00A1,Beagleboardtoys,BB-BONE-SERL-03
>>>> +		1: PF----  -1
>>>> +		2: PF----  -1
>>>> +		3: PF----  -1
>>>> +
>>>> +		WRITE:
>>>> +		  Writing a string of the form <part-number>[:version] issues a request to
>>>> +		  load a firmware blob containing an overlay. The name of the firmware blob
>>>> +		  is <part-number>-[version|00A0].dtbo. This act is defined as a slot override.
>>>> +
>>>> +		  Writing a negative slot id removes the slot if it was an overridden one, or
>>>> +		  unloads a slot that was probed.
>>>> +
>>>> +What:		/sys/devices/platform/bone_capemgr/baseboard/<eeprom-field>
>>>> +Date:		May 2015
>>>> +KernelVersion:	4.0
>>>> +Contact:	Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
>>>> +Description:	Contains the probed base board EEPROM field; one of:
>>>> +		board-name		- board-name as stored in cape EEPROM
>>>> +		dc-supplied		- whether the cape draws or supplies DC
>>>> +		eeprom-format-revision	- EEPROM format rev, only 00A0 supported
>>>> +		header			- header; should be 'aa 55 33 ee'
>>> 
>>> If it's always this value, why have the file?
>>> 
>> 
>> These are the contents of the EEPROM. If the format of the EEPROM changes then the
>> header information will change.
> 
> Then don't say "should be", because what happens in the future if it is
> not.
> 

OK

>>>> +		manufacturer		- manufacturer string
>>>> +		part-number		- part-number of the cape
>>>> +		serial-number		- serial number of the cape
>>>> +		version			- version of the cape, i.e. 00A0
>>>> +		number-of-pins		- displayed but ignored
>>>> +		pin-usage		- displayed but ignored
>>>> +		sys-5v			- displayed but ignored
>>>> +		vdd-3v3exp		- displayed but ignored
>>>> +		vdd-5v			- displayed but ignored
>>> 
>>> Are these all individual different files?
>>> 
>> 
>> Yes
> 
> Then write out the individual files please as different entries.
> 
> Also, the "displayed but ignored" doesn't make sense, please fix that
> up.
> 

OK

> greg k-h

Regards

— Pantelis

[PATCH 5/5] MAINTAINERS: Beaglebone capemanager maintainer

[Pantelis Antoniou]

Add me as the capemanager maintainer.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
---
 MAINTAINERS | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index c97e090..87611c0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1964,6 +1964,14 @@ W:	http://bcache.evilpiepirate.org
 S:	Maintained:
 F:	drivers/md/bcache/
 
+BEAGLEBONE CAPEMANAGER
+M:	Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
+S:	Maintained
+F:	drivers/misc/beaglebone-capemgr.c
+F:	Documentation/misc-devices/bone_capemgr.txt
+F:	Documentation/devicetree/bindings/misc/bone_capemgr.txt
+F:	Documentation/ABI/testing/sysfs-devices-platform-bone_capemgr
+
 BEFS FILE SYSTEM
 S:	Orphan
 F:	Documentation/filesystems/befs.txt
-- 
1.7.12