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mmc: cmdq_hci: Fix ADMA error issue 

The controller triggers an ADMA error when ADMA engine is configured
and used in 32-bit mode. This is because the current code always
writes 64-bit address to 32-bit address field of a transfer
descriptor (bits [63:32]). This corrupts the first 32-bit value
of the next transfer descriptor.

Below scenario describes how ADMA error can happen -

1. Req#1 - uses slot 1, prepares it's descriptors, queues to the controller
2. Req#2 - uses slot 0, prepares max descriptors (cq_host->mmc->max_segs).
3. Req#1 gets ADMA error from the controller.

At step 2, when it prepares the last transfer descriptor (max_segs), it
overwrites the 32-bit address field with a 64-bit address and thus corrupts
the first entry of slot 1 transfer descriptor.

Change-Id: I3eb2dbb40c76ec77626f647d6ec24df4a0858fcb
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
This commit is contained in:
Sahitya Tummala 2015-09-30 15:55:41 +05:30 committed by Gerrit - the friendly Code Review server
parent 17cc5c6354
commit c3abdef6e0
1 changed files with 12 additions and 5 deletions
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17
drivers/mmc/host/cmdq_hci.c
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@ -449,10 +449,9 @@ static int cmdq_dma_map(struct mmc_host *host, struct mmc_request *mrq)
return sg_count;
}
static void cmdq_set_tran_desc(u8 *desc,
dma_addr_t addr, int len, bool end)
static void cmdq_set_tran_desc(u8 *desc, dma_addr_t addr, int len,
bool end, bool is_dma64)
{
__le64 *dataddr = (__le64 __force *)(desc + 4);
__le32 *attr = (__le32 __force *)desc;
*attr = (VALID(1) |
@ -461,7 +460,15 @@ static void cmdq_set_tran_desc(u8 *desc,
ACT(0x4) |
DAT_LENGTH(len));
dataddr[0] = cpu_to_le64(addr);
if (is_dma64) {
__le64 *dataddr = (__le64 __force *)(desc + 4);
dataddr[0] = cpu_to_le64(addr);
} else {
__le32 *dataddr = (__le32 __force *)(desc + 4);
dataddr[0] = cpu_to_le32(addr);
}
}
static int cmdq_prep_tran_desc(struct mmc_request *mrq,
@ -490,7 +497,7 @@ static int cmdq_prep_tran_desc(struct mmc_request *mrq,
if ((i+1) == sg_count)
end = true;
cmdq_set_tran_desc(desc, addr, len, end);
cmdq_set_tran_desc(desc, addr, len, end, cq_host->dma64);
desc += cq_host->trans_desc_len;
}