Re: [-mm patch 2/3] AVR32 MTD: Unlock flash if necessary (try 2)

From: Haavard Skinnemoen
Date: Mon Sep 18 2006 - 04:12:24 EST


On Fri, 15 Sep 2006 16:32:26 +0100
David Woodhouse <dwmw2@xxxxxxxxxxxxx> wrote:

> On Fri, 2006-09-15 at 16:37 +0200, Haavard Skinnemoen wrote:
> > If a cfi_cmdset_0002 fixup installs an unlock() operation, use it
> > to unlock the whole flash after the erase regions have been set up.
>
> There are cmdset_0001 chips which have this affliction too. I was
> thinking of having a flag MTD_STUPID_LOCK which you set when you
> determine that it's one of these chips, then add_mtd_device() can do
> the unlocking... or add_mtd_partitions() can do it but _only_ for
> writable partitions.

Ok, so how about something like this? Which other chips should be marked?

---

From: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx>
Subject: [-mm patch 2/3] AVR32 MTD: Unlock flash if necessary

Introduce the MTD_STUPID_LOCK flag which indicates that the flash chip
is always locked after power-up, so all sectors need to be unlocked
before it is usable.

If this flag is set, and the chip provides an unlock() operation,
mtd_add_device will unlock the whole MTD device if it's writeable. This
means that non-writeable partitions will stay locked.

Set MTD_STUPID_LOCK in fixup_use_atmel_lock() so that these chips will
work as expected.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx>
---
drivers/mtd/chips/cfi_cmdset_0002.c | 1 +
drivers/mtd/mtdcore.c | 10 ++++++++++
include/mtd/mtd-abi.h | 1 +
3 files changed, 12 insertions(+)

Index: linux-2.6.18-rc6-mm2/drivers/mtd/chips/cfi_cmdset_0002.c
===================================================================
--- linux-2.6.18-rc6-mm2.orig/drivers/mtd/chips/cfi_cmdset_0002.c 2006-09-18 09:43:02.000000000 +0200
+++ linux-2.6.18-rc6-mm2/drivers/mtd/chips/cfi_cmdset_0002.c 2006-09-18 10:02:31.000000000 +0200
@@ -212,6 +212,7 @@ static void fixup_use_atmel_lock(struct
{
mtd->lock = cfi_atmel_lock;
mtd->unlock = cfi_atmel_unlock;
+ mtd->flags |= MTD_STUPID_LOCK;
}

static struct cfi_fixup cfi_fixup_table[] = {
Index: linux-2.6.18-rc6-mm2/drivers/mtd/mtdcore.c
===================================================================
--- linux-2.6.18-rc6-mm2.orig/drivers/mtd/mtdcore.c 2006-09-18 09:36:56.000000000 +0200
+++ linux-2.6.18-rc6-mm2/drivers/mtd/mtdcore.c 2006-09-18 10:03:24.000000000 +0200
@@ -57,6 +57,16 @@ int add_mtd_device(struct mtd_info *mtd)
mtd->index = i;
mtd->usecount = 0;

+ /* Some chips always power up locked. Unlock them now */
+ if ((mtd->flags & MTD_WRITEABLE)
+ && (mtd->flags & MTD_STUPID_LOCK) && mtd->unlock) {
+ if (mtd->unlock(mtd, 0, mtd->size))
+ printk(KERN_WARNING
+ "%s: unlock failed, "
+ "writes may not work\n",
+ mtd->name);
+ }
+
DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);
/* No need to get a refcount on the module containing
the notifier, since we hold the mtd_table_mutex */
Index: linux-2.6.18-rc6-mm2/include/mtd/mtd-abi.h
===================================================================
--- linux-2.6.18-rc6-mm2.orig/include/mtd/mtd-abi.h 2006-09-18 09:34:14.000000000 +0200
+++ linux-2.6.18-rc6-mm2/include/mtd/mtd-abi.h 2006-09-18 09:35:27.000000000 +0200
@@ -34,6 +34,7 @@ struct mtd_oob_buf {
#define MTD_WRITEABLE 0x400 /* Device is writeable */
#define MTD_BIT_WRITEABLE 0x800 /* Single bits can be flipped */
#define MTD_NO_ERASE 0x1000 /* No erase necessary */
+#define MTD_STUPID_LOCK 0x2000 /* Always locked after reset */

// Some common devices / combinations of capabilities
#define MTD_CAP_ROM 0
-
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