Hello.
On 03-03-2011 13:03, 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 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)
"Are" not needed.
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@xxxxxxxxxxx>
Signed-off-by: Ralph Hempel<ralph.hempel@xxxxxxxxxx>
Cc: David Woodhouse<dwmw2@xxxxxxxxxxxxx>
Cc: Daniel Schwierzeck<daniel.schwierzeck@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: linux-mtd@xxxxxxxxxxxxxxxxxxx
[...]
diff --git a/drivers/mtd/maps/Kconfig b/drivers/mtd/maps/Kconfig
index 5d37d31..587468e 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
Maybe you should select MTD_PARTITIONS instead?
[...]
diff --git a/drivers/mtd/maps/lantiq.c b/drivers/mtd/maps/lantiq.c
new file mode 100644
index 0000000..674be0a
--- /dev/null
+++ b/drivers/mtd/maps/lantiq.c
@@ -0,0 +1,190 @@
+/*
+ * 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/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
Period at end of statment missing?
+ * 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;
Empty line should be here, not above.
+ 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);
Hm, what does this lock gain, if the read is atomic anyway?
+void
+ltq_copy_from(struct map_info *map, void *to,
> + unsigned long from, ssize_t len)
Shouldn't it be static?
+{
+ unsigned char *p;
+ unsigned char *to_8;
+ unsigned long flags;
+
+ spin_lock_irqsave(&ebu_lock, flags);
+ from = (unsigned long) (map->virt + from);
Why not:
from += (unsigned long) map->virt;
like you do in ltq_copy_to()?
+ p = (unsigned char *) from;
Could be done in initializer, like in ltq_copy_to().
+ to_8 = (unsigned char *) to;
+ while (len--)
+ *to_8++ = *p++;
BTW, you could use memcpy_fromio().
+ spin_unlock_irqrestore(&ebu_lock, flags);
+}
+
+void
+ltq_copy_to(struct map_info *map, unsigned long to,
+ const void *from, ssize_t len)
Shouldn't it be static?
+{
+ 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++;
I think you have this backwards. It should be:
*to_8++ = *p++;
BTW, you could use memcpy_toio().
+ spin_unlock_irqrestore(&ebu_lock, flags);
+}
[...]
+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);
Cast from 'void *' is automatic -- no need for explicit one.
+#ifdef CONFIG_SOC_TYPE_XWAY
+ ltq_ebu_w32(ltq_ebu_r32(LTQ_EBU_BUSCON0) & ~EBU_WRDIS, LTQ_EBU_BUSCON0);
+#endif
Hm, can't you do this in the platform code?
+ 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);
Hm, could you indent the last line more to the right?
+ if (!ltq_map.virt) {
+ dev_err(&pdev->dev, "failed to ioremap!\n");
+ return -EIO;
+ }
+
+ ltq_mtd_probing = 1;
+ ltq_mtd = (struct mtd_info *) do_map_probe("cfi_probe",<q_map);
do_map_probe() already returns that type, why cast to it?
+ 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 = (struct cfi_private *)ltq_map.fldrv_priv;
Cast from 'void *' is automatic -- no need for explicit one.
+int __init
+init_ltq_mtd(void)
+{
+ int ret = platform_driver_register(<q_mtd_driver);
Use platform_driver_probe() instead, as the device is not a hotplug one.
Then ltq_mtd_probe() can become '__init'.
WBR, Sergei
