RFC: arm pcm043 1315.6 IM950 timing (Numonyx Axcell Errata)

["Tim Sander" <tim.sander@hbm.com>]

Hi

I just found out that Phytec has some patches in its BSP and i think especially the patches
IM590_cfi_workaround for "Numonyx Axcell P33/P30 Specification Update" make me a little nervous.

We had some Problems getting the latest HW Revision of PCM043 (1315.6) up and
running and so i found these patches. I have ported some other patches i found
(which i will send later today) but i don't know enough about CFI to apply this patch
logically to the barebox tree nevertheless heres my educated guess:
(I am not sure if the patch belongs into intel CFI but since Numonyx has been owned by
intel partly...)

commit bfa486c0bd90055222b4a2702bfb0d6a0fe59d8e
Author: Tim Sander <tim.sander@hbm.com>
Date:   Tue Aug 23 14:03:49 2011 +0200

    IM590 cfi workaround

diff --git a/drivers/nor/cfi_flash_intel.c b/drivers/nor/cfi_flash_intel.c
index c3cbad5..30a54e6 100644
--- a/drivers/nor/cfi_flash_intel.c
+++ b/drivers/nor/cfi_flash_intel.c
@@ -132,12 +132,30 @@ static int intel_flash_status_check (struct flash_info *info, flash_sect_t secto
 static int intel_flash_real_protect (struct flash_info *info, long sector, int prot)
 {
        flash_write_cmd (info, sector, 0, FLASH_CMD_CLEAR_STATUS);
+       //flash_write_cmd (info, sector, 0, FLASH_CMD_PROTECT);
+       /*
+       * see errata called
+       * "Numonyx Axcell P33/P30 Specification Update" :)
+       */
+       flash_write_cmd (info, sector, 0, FLASH_CMD_READ_ID);
+       flash_isequal (info, sector, FLASH_OFFSET_PROTECT, prot);
+       /*
+       * cmd must come before FLASH_CMD_PROTECT + 20us
+       * Disable interrupts which might cause a timeout here.
+       */
+#ifdef CONFIG_USE_IRQ
+       int flag = disable_interrupts ();
+#endif
        flash_write_cmd (info, sector, 0, FLASH_CMD_PROTECT);
        if (prot)
                flash_write_cmd (info, sector, 0, FLASH_CMD_PROTECT_SET);
        else
                flash_write_cmd (info, sector, 0, FLASH_CMD_PROTECT_CLEAR);
-
+       
+#ifdef CONFIG_USE_IRQ
+       if(flag)
+               enable_interrupts();
+#endif
        return 0;
 }


This patch is against u-boot-v2-rc10 *not* againts barebox as reference. It is taken from the 
PD10.1.2 BSP for PCM043.
Index: u-boot-2.0.0-rc10/drivers/nor/cfi_flash.c        
===================================================================
--- u-boot-2.0.0-rc10.orig/drivers/nor/cfi_flash.c  2011-01-28 10:52:14.881458149 +0100
+++ u-boot-2.0.0-rc10/drivers/nor/cfi_flash.c   2011-01-28 11:09:40.241981535 +0100
@@ -599,14 +599,34 @@
 static int flash_real_protect (flash_info_t * info, long sector, int prot)
 {
    int retcode = 0;
+   unsigned short cmd;

    flash_write_cmd (info, sector, 0, FLASH_CMD_CLEAR_STATUS);
-   flash_write_cmd (info, sector, 0, FLASH_CMD_PROTECT);
+   /*
+    * see errata called
+    * "Numonyx Axcell P33/P30 Specification Update" :)
+    */
+   flash_write_cmd (info, sector, 0, FLASH_CMD_READ_ID);
+   flash_isequal (info, sector, FLASH_OFFSET_PROTECT, prot);
+   /*
+    * cmd must come before FLASH_CMD_PROTECT + 20us
+    * Disable interrupts which might cause a timeout here.
+    */
+#ifdef CONFIG_USE_IRQ
+   int flag = disable_interrupts ();
+#endif
    if (prot)
-       flash_write_cmd (info, sector, 0, FLASH_CMD_PROTECT_SET);
+       cmd = FLASH_CMD_PROTECT_SET;
    else
-       flash_write_cmd (info, sector, 0, FLASH_CMD_PROTECT_CLEAR);
+       cmd = FLASH_CMD_PROTECT_CLEAR;

+   flash_write_cmd (info, sector, 0, FLASH_CMD_PROTECT);
+   flash_write_cmd (info, sector, 0, cmd);
+#ifdef CONFIG_USE_IRQ
+   /* re-enable interrupts if necessary */
+   if (flag)
+       enable_interrupts ();
+#endif
    if ((retcode =
         flash_full_status_check (info, sector, info->erase_blk_tout,
                      prot ? "protect" : "unprotect")) == 0) {

--
Please CC as i'm not subscribed to the list.

Best regards
Tim

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