Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma

[linux-flexiantxendom0-3.2.10.git] / drivers / mtd / nand / gpmi-nand / gpmi-lib.c

diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
index 2a200ba..590dd5c 100644 (file)
--- a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
@@ -69,17 +69,19 @@ static int clear_poll_bit(void __iomem *addr, u32 mask)
  *  [1] enable the module.
  *  [2] reset the module.
  *
- * In most of the cases, it's ok. But there is a hardware bug in the BCH block.
+ * In most of the cases, it's ok.
+ * But in MX23, there is a hardware bug in the BCH block (see erratum #2847).
  * If you try to soft reset the BCH block, it becomes unusable until
  * the next hard reset. This case occurs in the NAND boot mode. When the board
  * boots by NAND, the ROM of the chip will initialize the BCH blocks itself.
  * So If the driver tries to reset the BCH again, the BCH will not work anymore.
- * You will see a DMA timeout in this case.
+ * You will see a DMA timeout in this case. The bug has been fixed
+ * in the following chips, such as MX28.
  *
  * To avoid this bug, just add a new parameter `just_enable` for
  * the mxs_reset_block(), and rewrite it here.
  */
-int gpmi_reset_block(void __iomem *reset_addr, bool just_enable)
+static int gpmi_reset_block(void __iomem *reset_addr, bool just_enable)
 {
        int ret;
        int timeout = 0x400;
@@ -206,7 +208,15 @@ int bch_set_geometry(struct gpmi_nand_data *this)
        if (ret)
                goto err_out;
 
-       ret = gpmi_reset_block(r->bch_regs, true);
+       /*
+       * Due to erratum #2847 of the MX23, the BCH cannot be soft reset on this
+       * chip, otherwise it will lock up. So we skip resetting BCH on the MX23.
+       * On the other hand, the MX28 needs the reset, because one case has been
+       * seen where the BCH produced ECC errors constantly after 10000
+       * consecutive reboots. The latter case has not been seen on the MX23 yet,
+       * still we don't know if it could happen there as well.
+       */
+       ret = gpmi_reset_block(r->bch_regs, GPMI_IS_MX23(this));
        if (ret)
                goto err_out;