[PATCH V5 06/10] MIPS: lantiq: add NOR flash support

John Crispin
2011-03-30T07:27:04Z

NOR flash is attached to the same EBU (External Bus Unit) as PCI. As described
in the PCI patch, the EBU is a little buggy, resulting in the upper and lower
16 bit of the data on a 32 bit read are swapped. (essentially we have a addr^=2)

To work around this we do a addr^=2 during the probe. Once probed we adapt
cfi->addr_unlock1 and cfi->addr_unlock2 to represent the endianess bug.

Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Ralph Hempel <ralph.hempel@lantiq.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-mtd@lists.infradead.org

---

Changes in V2
* handle the endianess bug inside the map code and not in the generic cfi code
* remove the addr swizzle patch

Changes in V3
* whitespace
* change __iomem void to void __iomem

Chanegs in V4
* fixes a checkpatch.pl bug, the second is a false positive
* whitespace cleanups
* remove unused typecasts
* cleanup ltq_copy_from and ltq_copy_to

drivers/mtd/maps/Kconfig | 9 ++
drivers/mtd/maps/Makefile | 1 +
drivers/mtd/maps/lantiq.c | 181 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 191 insertions(+), 0 deletions(-)
create mode 100644 drivers/mtd/maps/lantiq.c

diff --git a/drivers/mtd/maps/Kconfig b/drivers/mtd/maps/Kconfig
index 44b1f46..83376d3 100644
--- a/drivers/mtd/maps/Kconfig
+++ b/drivers/mtd/maps/Kconfig
@@ -260,6 +260,15 @@ config MTD_BCM963XX
Support for parsing CFE image tag and creating MTD partitions on
Broadcom BCM63xx boards.

+config MTD_LANTIQ
+ bool "Lantiq SoC NOR support"
+ depends on LANTIQ
+ select MTD_PARTITIONS
+ help
+ Lantiq SoCs have a EBU (External Bus Unit). This IP allows to attach
+ a number of different peripherals to the SoC. This driver adds
+ support for NOR chips to be added.
+
config MTD_DILNETPC
tristate "CFI Flash device mapped on DIL/Net PC"
depends on X86 && MTD_PARTITIONS && MTD_CFI_INTELEXT && BROKEN
diff --git a/drivers/mtd/maps/Makefile b/drivers/mtd/maps/Makefile
index 08533bd..0db4ba3 100644
--- a/drivers/mtd/maps/Makefile
+++ b/drivers/mtd/maps/Makefile
@@ -60,3 +60,4 @@ obj-$(CONFIG_MTD_VMU) += vmu-flash.o
obj-$(CONFIG_MTD_GPIO_ADDR) += gpio-addr-flash.o
obj-$(CONFIG_MTD_BCM963XX) += bcm963xx-flash.o
obj-$(CONFIG_MTD_LATCH_ADDR) += latch-addr-flash.o
+obj-$(CONFIG_MTD_LANTIQ) += lantiq.o
diff --git a/drivers/mtd/maps/lantiq.c b/drivers/mtd/maps/lantiq.c
new file mode 100644
index 0000000..96a0b57
--- /dev/null
+++ b/drivers/mtd/maps/lantiq.c
@@ -0,0 +1,181 @@
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * Copyright (C) 2004 Liu Peng Infineon IFAP DC COM CPE
+ * Copyright (C) 2010 John Crispin <blogic@openwrt.org>
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/map.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/cfi.h>
+#include <linux/platform_device.h>
+#include <linux/mtd/physmap.h>
+
+#include <lantiq_soc.h>
+#include <lantiq_platform.h>
+
+/* the NOR flash is connected to the same external bus unit (EBU) as PCI.
+ * To make PCI work we need to enable the endianess swapping of the addr
+ * written to the EBU. this however has some limitations and breaks when
+ * using NOR. it does not really matter if the onflash data is in a swapped
+ * order, however cfi sequences also fail. to workaround this we need to use
+ * a complex map. We essentially software swap all addresses during probe
+ * and then swizzle the unlock addresses.
+ */
+static int ltq_mtd_probing;
+
+static map_word
+ltq_read16(struct map_info *map, unsigned long adr)
+{
+ unsigned long flags;
+ map_word temp;
+
+ if (ltq_mtd_probing)
+ adr ^= 2;
+ spin_lock_irqsave(&ebu_lock, flags);
+ temp.x[0] = *((__u16 *)(map->virt + adr));
+ spin_unlock_irqrestore(&ebu_lock, flags);
+ return temp;
+}
+
+static void
+ltq_write16(struct map_info *map, map_word d, unsigned long adr)
+{
+ unsigned long flags;
+
+ if (ltq_mtd_probing)
+ adr ^= 2;
+ spin_lock_irqsave(&ebu_lock, flags);
+ *((__u16 *)(map->virt + adr)) = d.x[0];
+ spin_unlock_irqrestore(&ebu_lock, flags);
+}
+
+static void
+ltq_copy_from(struct map_info *map, void *to,
+ unsigned long from, ssize_t len)
+{
+ unsigned char *f = (unsigned char *) (map->virt + from);
+ unsigned char *t = (unsigned char *) to;
+ unsigned long flags;
+
+ spin_lock_irqsave(&ebu_lock, flags);
+ while (len--)
+ *t++ = *f++;
+ spin_unlock_irqrestore(&ebu_lock, flags);
+}
+
+static void
+ltq_copy_to(struct map_info *map, unsigned long to,
+ const void *from, ssize_t len)
+{
+ unsigned char *f = (unsigned char *) from;
+ unsigned char *t = (unsigned char *) (map->virt + to);
+ unsigned long flags;
+
+ spin_lock_irqsave(&ebu_lock, flags);
+ while (len--)
+ *t++ = *f++;
+ spin_unlock_irqrestore(&ebu_lock, flags);
+}
+
+static const char const *part_probe_types[] = {
+ "cmdlinepart", NULL };
+
+static struct map_info ltq_map = {
+ .name = "ltq_nor",
+ .bankwidth = 2,
+ .read = ltq_read16,
+ .write = ltq_write16,
+ .copy_from = ltq_copy_from,
+ .copy_to = ltq_copy_to,
+};
+
+static int __init
+ltq_mtd_probe(struct platform_device *pdev)
+{
+ struct physmap_flash_data *ltq_mtd_data =
+ dev_get_platdata(&pdev->dev);
+ struct mtd_info *ltq_mtd = NULL;
+ struct mtd_partition *parts = NULL;
+ struct resource *res = 0;
+ int nr_parts = 0;
+ struct cfi_private *cfi;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "failed to get memory resource");
+ return -ENOENT;
+ }
+ res = devm_request_mem_region(&pdev->dev, res->start,
+ resource_size(res), dev_name(&pdev->dev));
+ if (!res) {
+ dev_err(&pdev->dev, "failed to request mem resource");
+ return -EBUSY;
+ }
+
+ ltq_map.phys = res->start;
+ ltq_map.size = resource_size(res);
+ ltq_map.virt = devm_ioremap_nocache(&pdev->dev, ltq_map.phys,
+ ltq_map.size);
+ if (!ltq_map.virt) {
+ dev_err(&pdev->dev, "failed to ioremap!\n");
+ return -EIO;
+ }
+
+ ltq_mtd_probing = 1;
+ ltq_mtd = do_map_probe("cfi_probe", &ltq_map);
+ ltq_mtd_probing = 0;
+ if (!ltq_mtd) {
+ iounmap(ltq_map.virt);
+ dev_err(&pdev->dev, "probing failed\n");
+ return -ENXIO;
+ }
+ ltq_mtd->owner = THIS_MODULE;
+
+ cfi = ltq_map.fldrv_priv;
+ cfi->addr_unlock1 ^= 1;
+ cfi->addr_unlock2 ^= 1;
+
+ nr_parts = parse_mtd_partitions(ltq_mtd, part_probe_types, &parts, 0);
+ if (nr_parts > 0) {
+ dev_info(&pdev->dev,
+ "using %d partitions from cmdline", nr_parts);
+ } else {
+ nr_parts = ltq_mtd_data->nr_parts;
+ parts = ltq_mtd_data->parts;
+ }
+
+ add_mtd_partitions(ltq_mtd, parts, nr_parts);
+ return 0;
+}
+
+static struct platform_driver ltq_mtd_driver = {
+ .driver = {
+ .name = "ltq_nor",
+ .owner = THIS_MODULE,
+ },
+};
+
+int __init
+init_ltq_mtd(void)
+{
+ int ret = platform_driver_probe(&ltq_mtd_driver, ltq_mtd_probe);
+
+ if (ret)
+ printk(KERN_INFO "ltq_nor: error registering platfom driver");
+ return ret;
+}
+
+module_init(init_ltq_mtd);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
+MODULE_DESCRIPTION("Lantiq SoC NOR");
--
1.7.2.3