Commit e9968c6f authored by Ulf Hansson's avatar Ulf Hansson
Browse files

mmc: mmci: Send a CMD12 to clear the DPSM at errors 



The current approach with sending a CMD12 (STOP_TRANSMISSION) to complete a
data transfer request, either because of using the open-ended transmission
type or because of receiving an error during a pre-defined data transfer,
isn't sufficient for the STM32 sdmmc variant. More precisely, this variant
needs to clear the DPSM ("Data Path State Machine") by sending a CMD12, for
all failing ADTC commands.

Support this, by adding a struct mmc_command inside the struct mmci_host
and initialize it to a CMD12 during ->probe(). Let's also add checks for
the new conditions, to enable mmci_data_irq() and mmci_cmd_irq() to
postpone the calls to mmci_request_end(), but instead send the CMD12.

Cc: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Tested-by: default avatarLudovic Barre <ludovic.barre@st.com>
parent e9d6a371

drivers/mmc/host/mmci.c

+23 −2
Original line number Diff line number Diff line
@@ -1127,6 +1127,12 @@ mmci_start_command(struct mmci_host *host, struct mmc_command *cmd, u32 c) 
	writel(c, base + MMCICOMMAND);

}



static void mmci_stop_command(struct mmci_host *host)

{

	host->stop_abort.error = 0;

	mmci_start_command(host, &host->stop_abort, 0);

}



static void

mmci_data_irq(struct mmci_host *host, struct mmc_data *data,

	      unsigned int status)
@@ -1196,12 +1202,18 @@ mmci_data_irq(struct mmci_host *host, struct mmc_data *data, 
			/* The error clause is handled above, success! */

			data->bytes_xfered = data->blksz * data->blocks;



		if (!data->stop || (host->mrq->sbc && !data->error))

			mmci_request_end(host, data->mrq);

		if (!data->stop) {

			if (host->variant->cmdreg_stop && data->error)

				mmci_stop_command(host);

			else

				mmci_request_end(host, data->mrq);

		} else if (host->mrq->sbc && !data->error) {

			mmci_request_end(host, data->mrq);

		} else {

			mmci_start_command(host, data->stop, 0);

		}

	}

}



static void

mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
@@ -1298,6 +1310,10 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd, 
			mmci_dma_error(host);



			mmci_stop_data(host);

			if (host->variant->cmdreg_stop && cmd->error) {

				mmci_stop_command(host);

				return;

			}

		}

		mmci_request_end(host, host->mrq);

	} else if (sbc) {
@@ -1956,6 +1972,11 @@ static int mmci_probe(struct amba_device *dev, 
		mmc->max_busy_timeout = 0;

	}



	/* Prepare a CMD12 - needed to clear the DPSM on some variants. */

	host->stop_abort.opcode = MMC_STOP_TRANSMISSION;

	host->stop_abort.arg = 0;

	host->stop_abort.flags = MMC_RSP_R1B | MMC_CMD_AC;



	mmc->ops = &mmci_ops;



	/* We support these PM capabilities. */

drivers/mmc/host/mmci.h

+1 −0
Original line number Diff line number Diff line
@@ -377,6 +377,7 @@ struct mmci_host { 
	void __iomem		*base;

	struct mmc_request	*mrq;

	struct mmc_command	*cmd;

	struct mmc_command	stop_abort;

	struct mmc_data		*data;

	struct mmc_host		*mmc;

	struct clk		*clk;