mmc/dw_mmc: Fix DMA descriptor corruption

In dwmci_prepare_data, the descriptors are allocated for DMA transfer.
These are allocated using the ALLOC_CACHE_ALIGN_BUFFER. This macro uses
the stack to allocate these descriptors. This becomes a problem if the
DMA transfer continues after the processor leaves the function in which
the descriptors were allocated.

Therefore, I have moved the allocated of the buffers up one level, to
dwmci_send_cmd(). The DMA transfer should be complete when leaving this
function.

Signed-off-by: Mischa Jonker <mjonker@synopsys.com>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Andy Fleming <afleming@gmail.com>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Acked-by: Pantelis Antoniou <panto@antoniou-consulting.com>

diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
index a82ee17a2503b51f8991f4171a1e9f45840dd80b..796a811876c7503faac7067f848eb994a68fd97c 100644 (file)
--- a/drivers/mmc/dw_mmc.c
+++ b/drivers/mmc/dw_mmc.c
@@ -41,12 +41,11 @@ static void dwmci_set_idma_desc(struct dwmci_idmac *idmac,
 }
 
 static void dwmci_prepare_data(struct dwmci_host *host,
-               struct mmc_data *data)
+               struct mmc_data *data, struct dwmci_idmac *cur_idmac)
 {
        unsigned long ctrl;
        unsigned int i = 0, flags, cnt, blk_cnt;
        ulong data_start, data_end, start_addr;
-       ALLOC_CACHE_ALIGN_BUFFER(struct dwmci_idmac, cur_idmac, data->blocks);
 
 
        blk_cnt = data->blocks;
@@ -111,6 +110,8 @@ static int dwmci_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
                struct mmc_data *data)
 {
        struct dwmci_host *host = (struct dwmci_host *)mmc->priv;
+       ALLOC_CACHE_ALIGN_BUFFER(struct dwmci_idmac, cur_idmac,
+                                data ? data->blocks : 0);
        int flags = 0, i;
        unsigned int timeout = 100000;
        u32 retry = 10000;
@@ -127,7 +128,7 @@ static int dwmci_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
        dwmci_writel(host, DWMCI_RINTSTS, DWMCI_INTMSK_ALL);
 
        if (data)
-               dwmci_prepare_data(host, data);
+               dwmci_prepare_data(host, data, cur_idmac);
 
        dwmci_writel(host, DWMCI_CMDARG, cmd->cmdarg);