[MTD] [NAND] atmel_nand: Work around AT32AP7000 ECC erratum

[linux-2.6-omap-h63xx.git] / drivers / mtd / nand / atmel_nand.c

diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index 4814fc9b237bffe0091defd9922a395b0e3465fd..99aec46e21450565e3e323adccfcb1f077597511 100644 (file)
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -33,6 +33,7 @@
 #include <linux/io.h>
 
 #include <asm/arch/board.h>
+#include <asm/arch/cpu.h>
 
 #ifdef CONFIG_MTD_NAND_ATMEL_ECC_HW
 #define hard_ecc       1
@@ -264,6 +265,19 @@ static int atmel_nand_read_page(struct mtd_info *mtd,
        uint8_t *ecc_pos;
        int stat;
 
+       /*
+        * Errata: ALE is incorrectly wired up to the ECC controller
+        * on the AP7000, so it will include the address cycles in the
+        * ECC calculation.
+        *
+        * Workaround: Reset the parity registers before reading the
+        * actual data.
+        */
+       if (cpu_is_at32ap7000()) {
+               struct atmel_nand_host *host = chip->priv;
+               ecc_writel(host->ecc, CR, ATMEL_ECC_RST);
+       }
+
        /* read the page */
        chip->read_buf(mtd, p, eccsize);
 
@@ -377,9 +391,16 @@ static int atmel_nand_correct(struct mtd_info *mtd, u_char *dat,
 }
 
 /*
- * Enable HW ECC : unsused
+ * Enable HW ECC : unused on most chips
  */
-static void atmel_nand_hwctl(struct mtd_info *mtd, int mode) { ; }
+static void atmel_nand_hwctl(struct mtd_info *mtd, int mode)
+{
+       if (cpu_is_at32ap7000()) {
+               struct nand_chip *nand_chip = mtd->priv;
+               struct atmel_nand_host *host = nand_chip->priv;
+               ecc_writel(host->ecc, CR, ATMEL_ECC_RST);
+       }
+}
 
 #ifdef CONFIG_MTD_PARTITIONS
 static const char *part_probes[] = { "cmdlinepart", NULL };