Hi John,
the EBU doesn't allow unaligned read or write access thus Lantiq added
this alignment hack directly in hardware. The addr^=2 is only needed
during CFI probe because odd addresses are accessed. A simple solution
is inside your patch.
The spin_lock_irqsave(&ebu_lock, flags); is actually not needed because
the EBU does access arbitration and protection already in hardware.
Daniel
On 01/05/2011 08:56 PM, John Crispin wrote:
NOR flash is attached to the same EBU (External Bus Unit) as PCI. As described
in the PCI patch, the EBU is a little obscure, resulting in the upper and lower
16 bit of the data on a 32 bit read are swapped. (essentially we have a addr^=2)
This only happens on the read of data. In order to not have to high an impact
on the read performance from the EBU we store all data on the flash with
addr^=2. This allows us to do generic reads without having to do any swapping.
For the write to now work we need to swizzle the the 0x2 bit of the addr.
However this write swizzle needs to only happen when doing a CMD and not a DATA
write.
As the MTD layer currently makes no difference between a CMD and DATA read when
using complex maps, the map driver does not know when the swizzle and when not
to swizzle. The next patch in the series adds a hack to the MTD to workaround
this problem. I am sending these 2 patches to the mtd list aswell. There are
several ways to solve this generically in the mtd layer in a much better way.
This will have minor impact on the actual map code provided in this patch.
Signed-off-by: John Crispin<blogic@xxxxxxxxxxx>
Signed-off-by: Ralph Hempel<ralph.hempel@xxxxxxxxxx>
Cc: David Woodhouse<dwmw2@xxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: linux-mtd@xxxxxxxxxxxxxxxxxxx
---
drivers/mtd/maps/Kconfig | 7 ++
drivers/mtd/maps/Makefile | 1 +
drivers/mtd/maps/lantiq.c | 169 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 177 insertions(+), 0 deletions(-)
create mode 100644 drivers/mtd/maps/lantiq.c
diff --git a/drivers/mtd/maps/Kconfig b/drivers/mtd/maps/Kconfig
index a0dd7bb..ca69a7f 100644
--- a/drivers/mtd/maps/Kconfig
+++ b/drivers/mtd/maps/Kconfig
@@ -260,6 +260,13 @@ 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&& MTD_PARTITIONS
+ help
+ Support for NOR flash chips on Lantiq SoC. The Chips are connected
+ to the SoCs EBU (External Bus Unit)
+
config MTD_DILNETPC
tristate "CFI Flash device mapped on DIL/Net PC"
depends on X86&& MTD_CONCAT&& MTD_PARTITIONS&& MTD_CFI_INTELEXT&& BROKEN
diff --git a/drivers/mtd/maps/Makefile b/drivers/mtd/maps/Makefile
index c7869c7..bb2ce2f 100644
--- a/drivers/mtd/maps/Makefile
+++ b/drivers/mtd/maps/Makefile
@@ -59,3 +59,4 @@ obj-$(CONFIG_MTD_RBTX4939) += rbtx4939-flash.o
obj-$(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_LANTIQ) += lantiq.o
diff --git a/drivers/mtd/maps/lantiq.c b/drivers/mtd/maps/lantiq.c
new file mode 100644
index 0000000..e5a361e
--- /dev/null
+++ b/drivers/mtd/maps/lantiq.c
@@ -0,0 +1,169 @@
+/*
+ * 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@xxxxxxxxxxx>
+ */
+
+#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/magic.h>
+#include<linux/platform_device.h>
+#include<linux/mtd/physmap.h>
+
+#include<lantiq_soc.h>
+#include<lantiq_platform.h>
+
static int ltq_probing = 0;
+static map_word
+ltq_read16(struct map_info *map, unsigned long adr)
+{
+ unsigned long flags;
+ map_word temp;
+ spin_lock_irqsave(&ebu_lock, flags);
if (ltq_probing)
adr ^= 2;
+ 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;
+ spin_lock_irqsave(&ebu_lock, flags);
if (ltq_probing)
adr ^= 2;
+ *((__u16 *)(map->virt + adr)) = d.x[0];
+ spin_unlock_irqrestore(&ebu_lock, flags);
+}
+
+void
+ltq_copy_from(struct map_info *map, void *to,
+ unsigned long from, ssize_t len)
+{
+ unsigned char *p;
+ unsigned char *to_8;
+ unsigned long flags;
+ spin_lock_irqsave(&ebu_lock, flags);
+ from = (unsigned long)(from + map->virt);
+ p = (unsigned char *) from;
+ to_8 = (unsigned char *) to;
+ while (len--)
+ *to_8++ = *p++;
+ spin_unlock_irqrestore(&ebu_lock, flags);
+}
+
+void
+ltq_copy_to(struct map_info *map, unsigned long to,
+ const void *from, ssize_t len)
+{
+ unsigned char *p = (unsigned char *)from;
+ unsigned char *to_8;
+ unsigned long flags;
+ spin_lock_irqsave(&ebu_lock, flags);
+ to += (unsigned long) map->virt;
+ to_8 = (unsigned char *)to;
+ while (len--)
+ *p++ = *to_8++;
+ 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
+ltq_mtd_probe(struct platform_device *pdev)
+{
+ struct physmap_flash_data *ltq_mtd_data =
+ (struct physmap_flash_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;
+
+#ifdef CONFIG_SOC_TYPE_XWAY
+ ltq_w32(ltq_r32(LTQ_EBU_BUSCON0)& ~EBU_WRDIS, LTQ_EBU_BUSCON0);
+#endif
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "failed to get memory resource");
+ return -ENOENT;
+ }
+ res = request_mem_region(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 = ioremap_nocache(ltq_map.phys, ltq_map.size);
+
+ if (!ltq_map.virt) {
+ dev_err(&pdev->dev, "failed to ioremap!\n");
+ return -EIO;
+ }
+
ltq_probing = 1;
+ ltq_mtd = (struct mtd_info *) do_map_probe("cfi_probe",<q_map);
ltq_probing = 0;
+ if (!ltq_mtd) {
+ iounmap(ltq_map.virt);
+ dev_err(&pdev->dev, "probing failed\n");
+ return -ENXIO;
+ }
+
+ ltq_mtd->owner = THIS_MODULE;
+
+ 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 = {
+ .probe = ltq_mtd_probe,
+ .driver = {
+ .name = "ltq_nor",
+ .owner = THIS_MODULE,
+ },
+};
+
+int __init
+init_ltq_mtd(void)
+{
+ int ret = platform_driver_register(<q_mtd_driver);
+ 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@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Lantiq SoC NOR");
