[PATCH] powerpc/powernv: Platform dump interface

[Vasant Hegde <hegdevasant@linux.vnet.ibm.com>]

This patch adds Platform dump retrieval interface.

Flow:
  - We register to OPAL notification event.
  - OPAL sends new dump available notification.
  - We retrieve the dump and send it to debugfs.
  - User copies the dump data and end ACKs via debugfs.
  - We send ACK to OPAL.

debugfs files:
  We create below dump related files under "fsp" directory.
  - dump		: Dump data
  - dump_available	: New dump available notification to userspace
  - dump_control	: ACK/initiate new dump
  - README		: README

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/opal.h                |   12 +
 arch/powerpc/platforms/powernv/Makefile        |    2 
 arch/powerpc/platforms/powernv/opal-dump.c     |  420 ++++++++++++++++++++++++
 arch/powerpc/platforms/powernv/opal-wrappers.S |    4 
 arch/powerpc/platforms/powernv/opal.c          |    2 
 5 files changed, 438 insertions(+), 2 deletions(-)
 create mode 100644 arch/powerpc/platforms/powernv/opal-dump.c

diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index d1af862..a1c5237 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -154,6 +154,10 @@ extern int opal_enter_rtas(struct rtas_args *args,
 #define OPAL_FLASH_VALIDATE			76
 #define OPAL_FLASH_MANAGE			77
 #define OPAL_FLASH_UPDATE			78
+#define OPAL_DUMP_INIT				81
+#define OPAL_DUMP_INFO				82
+#define OPAL_DUMP_READ				83
+#define OPAL_DUMP_ACK				84
 
 #ifndef __ASSEMBLY__
 
@@ -233,7 +237,8 @@ enum OpalPendingState {
 	OPAL_EVENT_ERROR_LOG		= 0x40,
 	OPAL_EVENT_EPOW			= 0x80,
 	OPAL_EVENT_LED_STATUS		= 0x100,
-	OPAL_EVENT_PCI_ERROR		= 0x200
+	OPAL_EVENT_PCI_ERROR		= 0x200,
+	OPAL_EVENT_DUMP_AVAIL		= 0x400,
 };
 
 /* Machine check related definitions */
@@ -752,6 +757,10 @@ int64_t opal_lpc_read(uint32_t chip_id, enum OpalLPCAddressType addr_type,
 int64_t opal_validate_flash(uint64_t buffer, uint32_t *size, uint32_t *result);
 int64_t opal_manage_flash(uint8_t op);
 int64_t opal_update_flash(uint64_t blk_list);
+int64_t opal_dump_init(uint8_t dump_type);
+int64_t opal_dump_info(uint32_t *dump_id, uint32_t *dump_size);
+int64_t opal_dump_read(uint32_t dump_id, uint64_t buffer);
+int64_t opal_dump_ack(uint32_t dump_id);
 
 /* Internal functions */
 extern int early_init_dt_scan_opal(unsigned long node, const char *uname, int depth, void *data);
@@ -781,6 +790,7 @@ extern void opal_get_rtc_time(struct rtc_time *tm);
 extern unsigned long opal_get_boot_time(void);
 extern void opal_nvram_init(void);
 extern void opal_flash_init(void);
+extern void opal_platform_dump_init(void);
 
 extern int opal_machine_check(struct pt_regs *regs);
 
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index 873fa13..379b215 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -1,6 +1,6 @@
 obj-y			+= setup.o opal-takeover.o opal-wrappers.o opal.o
 obj-y			+= opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
-obj-y			+= rng.o
+obj-y			+= rng.o opal-dump.o
 
 obj-$(CONFIG_SMP)	+= smp.o
 obj-$(CONFIG_PCI)	+= pci.o pci-p5ioc2.o pci-ioda.o
diff --git a/arch/powerpc/platforms/powernv/opal-dump.c b/arch/powerpc/platforms/powernv/opal-dump.c
new file mode 100644
index 0000000..e102a80
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-dump.c
@@ -0,0 +1,420 @@
+/*
+ * PowerNV OPAL Dump Interface
+ *
+ * Copyright 2013 IBM Corp.
+ *
+ * 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.
+ */
+
+#include <linux/kobject.h>
+#include <linux/debugfs.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/pagemap.h>
+#include <linux/delay.h>
+
+#include <asm/opal.h>
+
+/* Dump type */
+#define DUMP_TYPE_FSP	0x01
+
+/* Extract failed */
+#define DUMP_NACK_ID	0x00
+
+/* Dump record */
+struct dump_record {
+	uint8_t		type;
+	uint32_t	id;
+	uint32_t	size;
+	char		*buffer;
+};
+static struct dump_record dump_record;
+
+/* Dump available status */
+static u32 dump_avail;
+
+/* Binary blobs */
+static struct debugfs_blob_wrapper dump_blob;
+static struct debugfs_blob_wrapper readme_blob;
+
+/* Ignore dump notification, if we fail to create debugfs files */
+static bool dump_disarmed = false;
+
+
+static void free_dump_sg_list(struct opal_sg_list *list)
+{
+	struct opal_sg_list *sg1;
+	while (list) {
+		sg1 = list->next;
+		kfree(list);
+		list = sg1;
+	}
+	list = NULL;
+}
+
+/*
+ * Build dump buffer scatter gather list
+ */
+static struct opal_sg_list *dump_data_to_sglist(void)
+{
+	struct opal_sg_list *sg1, *list = NULL;
+	void *addr;
+	int64_t size;
+
+	addr = dump_record.buffer;
+	size = dump_record.size;
+
+	sg1 = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!sg1)
+		goto nomem;
+
+	list = sg1;
+	sg1->num_entries = 0;
+	while (size > 0) {
+		/* Translate virtual address to physical address */
+		sg1->entry[sg1->num_entries].data =
+			(void *)(vmalloc_to_pfn(addr) << PAGE_SHIFT);
+
+		if (size > PAGE_SIZE)
+			sg1->entry[sg1->num_entries].length = PAGE_SIZE;
+		else
+			sg1->entry[sg1->num_entries].length = size;
+
+		sg1->num_entries++;
+		if (sg1->num_entries >= SG_ENTRIES_PER_NODE) {
+			sg1->next = kzalloc(PAGE_SIZE, GFP_KERNEL);
+			if (!sg1->next)
+				goto nomem;
+
+			sg1 = sg1->next;
+			sg1->num_entries = 0;
+		}
+		addr += PAGE_SIZE;
+		size -= PAGE_SIZE;
+	}
+	return list;
+
+nomem:
+	pr_err("%s : Failed to allocate memory\n", __func__);
+	free_dump_sg_list(list);
+	return NULL;
+}
+
+/*
+ * Translate sg list address to absolute
+ */
+static void sglist_to_phy_addr(struct opal_sg_list *list)
+{
+	struct opal_sg_list *sg, *next;
+
+	for (sg = list; sg; sg = next) {
+		next = sg->next;
+		/* Don't translate NULL pointer for last entry */
+		if (sg->next)
+			sg->next = (struct opal_sg_list *)__pa(sg->next);
+		else
+			sg->next = NULL;
+
+		/* Convert num_entries to length */
+		sg->num_entries =
+			sg->num_entries * sizeof(struct opal_sg_entry) + 16;
+	}
+}
+
+static void free_dump_data_buf(void)
+{
+	vfree(dump_record.buffer);
+	dump_record.size = 0;
+}
+
+/*
+ * Allocate dump data buffer.
+ */
+static int alloc_dump_data_buf(void)
+{
+	dump_record.buffer = vzalloc(PAGE_ALIGN(dump_record.size));
+	if (!dump_record.buffer) {
+		pr_err("%s : Failed to allocate memory\n", __func__);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+/*
+ * Initiate FipS dump
+ */
+static int64_t dump_fips_init(uint8_t type)
+{
+	int rc;
+
+	rc = opal_dump_init(type);
+	if (rc)
+		pr_warn("%s: Failed to initiate FipS dump (%d)\n",
+			__func__, rc);
+	return rc;
+}
+
+/*
+ * Get dump ID and size.
+ */
+static int64_t dump_read_info(void)
+{
+	int rc;
+
+	rc = opal_dump_info(&dump_record.id, &dump_record.size);
+	if (rc)
+		pr_warn("%s: Failed to get dump info (%d)\n",
+			__func__, rc);
+	return rc;
+}
+
+/*
+ * Send acknoledgement to OPAL
+ */
+static int64_t dump_send_ack(uint32_t dump_id)
+{
+	int rc;
+
+	rc = opal_dump_ack(dump_id);
+	if (rc)
+		pr_warn("%s: Failed to send ack message to ID 0x%x (%d)\n",
+			__func__, dump_id, rc);
+	return rc;
+}
+
+/*
+ * Retrieve dump data
+ */
+static int64_t dump_read_data(void)
+{
+	struct opal_sg_list *list;
+	uint64_t addr;
+	int64_t rc;
+
+	/* Allocate memory */
+	rc = alloc_dump_data_buf();
+	if (rc)
+		goto out;
+
+	/* Generate SG list */
+	list = dump_data_to_sglist();
+	if (!list) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	/* Translate sg list addr to real address */
+	sglist_to_phy_addr(list);
+
+	/* First entry address */
+	addr = __pa(list);
+
+	/* Fetch data */
+	rc = OPAL_BUSY;
+	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
+		rc = opal_dump_read(dump_record.id, addr);
+		if (rc == OPAL_BUSY) {
+			opal_poll_events(NULL);
+			mdelay(10);
+		}
+	}
+
+	if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL)
+		pr_warn("%s: Extract dump failed for ID 0x%x\n",
+			__func__, dump_record.id);
+
+	/* Free SG list */
+	free_dump_sg_list(list);
+
+out:
+	return rc;
+}
+
+static int extract_dump(void)
+{
+	int rc;
+
+	/* Get dump ID, size */
+	rc = dump_read_info();
+	if (rc != OPAL_SUCCESS)
+		return rc;
+
+	/* Read dump data */
+	rc = dump_read_data();
+	if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL) {
+		/*
+		 * Failed to allocate memory to retrieve dump. Lets send
+		 * negative ack so that we get notification again.
+		 */
+		dump_send_ack(DUMP_NACK_ID);
+
+		/* Free dump buffer */
+		free_dump_data_buf();
+
+		return rc;
+	}
+	if (rc == OPAL_PARTIAL)
+		pr_info("%s: Partially read dump ID 0x%x\n",
+			__func__, dump_record.id);
+
+	pr_info("%s: New platform dump available. ID = 0x%x\n",
+		__func__, dump_record.id);
+
+	/* Update dump blob */
+	dump_blob.data = (void *)dump_record.buffer;
+	dump_blob.size = dump_record.size;
+
+	/* Update dump available status */
+	dump_avail = 1;
+
+	return rc;
+}
+
+static void dump_extract_fn(struct work_struct *work)
+{
+	extract_dump();
+}
+
+static DECLARE_WORK(dump_work, dump_extract_fn);
+
+/* Workqueue to extract dump */
+static void schedule_extract_dump(void)
+{
+	schedule_work(&dump_work);
+}
+
+/*
+ * New dump available notification
+ *
+ * Once we get notification, we extract dump via OPAL call
+ * and then write dump to file.
+ */
+static int dump_event(struct notifier_block *nb,
+		      unsigned long events, void *change)
+{
+	/*
+	 * Don't retrieve dump, if we don't have debugfs
+	 * interface to pass data to userspace.
+	 */
+	if (dump_disarmed)
+		return 0;
+
+	/* Check for dump available notification */
+	if (events & OPAL_EVENT_DUMP_AVAIL)
+		schedule_extract_dump();
+
+	return 0;
+}
+
+static struct notifier_block dump_nb = {
+	.notifier_call  = dump_event,
+	.next           = NULL,
+	.priority       = 0
+};
+
+
+/* FIXME: debugfs README message */
+static const char readme_msg[] =
+	"This file will be populated shortly..";
+
+/* debugfs dump_control file operations */
+static ssize_t dump_control_write(struct file *file,
+				  const char __user *user_buf,
+				  size_t count, loff_t *ppos)
+{
+	char buf[4];
+	size_t buf_size;
+
+	buf_size = min(count, (sizeof(buf) - 1));
+	if (copy_from_user(buf, user_buf, buf_size))
+		return -EFAULT;
+
+	switch (buf[0]) {
+	case '1':	/* Dump send ack */
+		if (dump_avail) {
+			dump_avail = 0;
+			free_dump_data_buf();
+			dump_send_ack(dump_record.id);
+		}
+		break;
+	case '2':	/* Initiate FipS dump */
+		dump_fips_init(DUMP_TYPE_FSP);
+		break;
+	default:
+		break;
+	}
+	return count;
+}
+
+static const struct file_operations dump_control_fops = {
+	.open	= simple_open,
+	.write	= dump_control_write,
+	.llseek	= default_llseek,
+};
+
+/*
+ * Create dump debugfs file
+ */
+static int debugfs_dump_init(void)
+{
+	struct dentry *dir, *file;
+
+	/* FSP dump directory */
+	dir = debugfs_create_dir("fsp", NULL);
+	if (!dir)
+		goto out;
+
+	/* README */
+	readme_blob.data = (void *)readme_msg;
+	readme_blob.size = strlen(readme_msg);
+	file = debugfs_create_blob("README", 0400, dir, &readme_blob);
+	if (!file)
+		goto remove_dir;
+
+	/* Dump available notification */
+	file = debugfs_create_u32("dump_avail", 0400, dir, &dump_avail);
+	if (!file)
+		goto remove_dir;
+
+	/* data file */
+	dump_blob.data = (void *)dump_record.buffer;
+	dump_blob.size = dump_record.size;
+	file = debugfs_create_blob("dump", 0400, dir, &dump_blob);
+	if (!file)
+		goto remove_dir;
+
+	/* Control file */
+	file = debugfs_create_file("dump_control", 0200, dir,
+				   NULL, &dump_control_fops);
+	if (!file)
+		goto remove_dir;
+
+	return 0;
+
+remove_dir:
+	debugfs_remove_recursive(dir);
+
+out:
+	dump_disarmed = true;
+	return -1;
+}
+
+void __init opal_platform_dump_init(void)
+{
+	int ret;
+
+	/* Register for opal notifier */
+	ret = opal_notifier_register(&dump_nb);
+	if (ret) {
+		pr_warn("%s: Can't register OPAL event notifier (%d)\n",
+			__func__, ret);
+		return;
+	}
+
+	/* debugfs interface */
+	ret = debugfs_dump_init();
+}
diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index e780650..1485a09 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -126,3 +126,7 @@ OPAL_CALL(opal_return_cpu,			OPAL_RETURN_CPU);
 OPAL_CALL(opal_validate_flash,			OPAL_FLASH_VALIDATE);
 OPAL_CALL(opal_manage_flash,			OPAL_FLASH_MANAGE);
 OPAL_CALL(opal_update_flash,			OPAL_FLASH_UPDATE);
+OPAL_CALL(opal_dump_init,			OPAL_DUMP_INIT);
+OPAL_CALL(opal_dump_info,			OPAL_DUMP_INFO);
+OPAL_CALL(opal_dump_read,			OPAL_DUMP_READ);
+OPAL_CALL(opal_dump_ack,			OPAL_DUMP_ACK);
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 1c798cd..7c7524c 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -442,6 +442,8 @@ static int __init opal_init(void)
 	if (rc == 0) {
 		/* Setup code update interface */
 		opal_flash_init();
+		/* Setup platform dump extract interface */
+		opal_platform_dump_init();
 	}
 
 	return 0;