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Commit e0cc2601 authored by Sahitya Tummala's avatar Sahitya Tummala Committed by Gerrit - the friendly Code Review server
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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: default avatarSahitya Tummala <stummala@codeaurora.org>
parent 1c6b02e6

drivers/mmc/host/cmdq_hci.c

+12 −5
Original line number Diff line number Diff line
@@ -486,10 +486,9 @@ 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) |
@@ -498,7 +497,15 @@ static void cmdq_set_tran_desc(u8 *desc, 
		 ACT(0x4) |

		 DAT_LENGTH(len));



	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,
@@ -527,7 +534,7 @@ 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;

	}