Commit ed01d210 authored by Linus Walleij's avatar Linus Walleij Committed by Ulf Hansson
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mmc: davinci_mmc: Use sg_miter for PIO 



Use the scatterlist memory iterator instead of just
dereferencing virtual memory using sg_virt().
This make highmem references work properly.

Suggested-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/linux-mmc/20240122073423.GA25859@lst.de/


Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240127-mmc-proper-kmap-v2-1-d8e732aa97d1@linaro.org


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 3a999e57

drivers/mmc/host/davinci_mmc.c

+28 −33
Original line number Diff line number Diff line
@@ -180,12 +180,6 @@ struct mmc_davinci_host { 
#define DAVINCI_MMC_DATADIR_WRITE	2

	unsigned char data_dir;



	/* buffer is used during PIO of one scatterlist segment, and

	 * is updated along with buffer_bytes_left.  bytes_left applies

	 * to all N blocks of the PIO transfer.

	 */

	u8 *buffer;

	u32 buffer_bytes_left;

	u32 bytes_left;



	struct dma_chan *dma_tx;
@@ -196,8 +190,8 @@ struct mmc_davinci_host { 
	bool active_request;



	/* For PIO we walk scatterlists one segment at a time. */

	struct sg_mapping_iter sg_miter;

	unsigned int		sg_len;

	struct scatterlist *sg;



	/* Version of the MMC/SD controller */

	u8 version;
@@ -213,30 +207,24 @@ struct mmc_davinci_host { 
static irqreturn_t mmc_davinci_irq(int irq, void *dev_id);



/* PIO only */

static void mmc_davinci_sg_to_buf(struct mmc_davinci_host *host)

{

	host->buffer_bytes_left = sg_dma_len(host->sg);

	host->buffer = sg_virt(host->sg);

	if (host->buffer_bytes_left > host->bytes_left)

		host->buffer_bytes_left = host->bytes_left;

}



static void davinci_fifo_data_trans(struct mmc_davinci_host *host,

					unsigned int n)

{

	struct sg_mapping_iter *sgm = &host->sg_miter;

	size_t sglen;

	u8 *p;

	unsigned int i;



	if (host->buffer_bytes_left == 0) {

		host->sg = sg_next(host->data->sg);

		mmc_davinci_sg_to_buf(host);

	/*

	 * By adjusting sgm->consumed this will give a pointer to the

	 * current index into the sgm.

	 */

	if (!sg_miter_next(sgm)) {

		dev_err(mmc_dev(host->mmc), "ran out of sglist prematurely\n");

		return;

	}



	p = host->buffer;

	if (n > host->buffer_bytes_left)

		n = host->buffer_bytes_left;

	host->buffer_bytes_left -= n;

	host->bytes_left -= n;

	p = sgm->addr;

	sglen = sgm->length;



	/* NOTE:  we never transfer more than rw_threshold bytes

	 * to/from the fifo here; there's no I/O overlap.
@@ -261,7 +249,9 @@ static void davinci_fifo_data_trans(struct mmc_davinci_host *host, 
			p = p + (n & 3);

		}

	}

	host->buffer = p;



	sgm->consumed = n;

	host->bytes_left -= n;

}



static void mmc_davinci_start_command(struct mmc_davinci_host *host,
@@ -517,6 +507,7 @@ mmc_davinci_prepare_data(struct mmc_davinci_host *host, struct mmc_request *req) 
	int fifo_lev = (rw_threshold == 32) ? MMCFIFOCTL_FIFOLEV : 0;

	int timeout;

	struct mmc_data *data = req->data;

	unsigned int flags = SG_MITER_ATOMIC; /* Used from IRQ */



	if (host->version == MMC_CTLR_VERSION_2)

		fifo_lev = (rw_threshold == 64) ? MMCFIFOCTL_FIFOLEV : 0;
@@ -545,12 +536,14 @@ mmc_davinci_prepare_data(struct mmc_davinci_host *host, struct mmc_request *req) 


	/* Configure the FIFO */

	if (data->flags & MMC_DATA_WRITE) {

		flags |= SG_MITER_FROM_SG;

		host->data_dir = DAVINCI_MMC_DATADIR_WRITE;

		writel(fifo_lev | MMCFIFOCTL_FIFODIR_WR | MMCFIFOCTL_FIFORST,

			host->base + DAVINCI_MMCFIFOCTL);

		writel(fifo_lev | MMCFIFOCTL_FIFODIR_WR,

			host->base + DAVINCI_MMCFIFOCTL);

	} else {

		flags |= SG_MITER_TO_SG;

		host->data_dir = DAVINCI_MMC_DATADIR_READ;

		writel(fifo_lev | MMCFIFOCTL_FIFODIR_RD | MMCFIFOCTL_FIFORST,

			host->base + DAVINCI_MMCFIFOCTL);
@@ -558,7 +551,6 @@ mmc_davinci_prepare_data(struct mmc_davinci_host *host, struct mmc_request *req) 
			host->base + DAVINCI_MMCFIFOCTL);

	}



	host->buffer = NULL;

	host->bytes_left = data->blocks * data->blksz;



	/* For now we try to use DMA whenever we won't need partial FIFO
@@ -576,8 +568,7 @@ mmc_davinci_prepare_data(struct mmc_davinci_host *host, struct mmc_request *req) 
	} else {

		/* Revert to CPU Copy */

		host->sg_len = data->sg_len;

		host->sg = host->data->sg;

		mmc_davinci_sg_to_buf(host);

		sg_miter_start(&host->sg_miter, data->sg, data->sg_len, flags);

	}

}
@@ -843,6 +834,8 @@ davinci_abort_data(struct mmc_davinci_host *host, struct mmc_data *data) 
{

	mmc_davinci_reset_ctrl(host, 1);

	mmc_davinci_reset_ctrl(host, 0);

	if (!host->do_dma)

		sg_miter_stop(&host->sg_miter);

}



static irqreturn_t mmc_davinci_sdio_irq(int irq, void *dev_id)
@@ -919,11 +912,13 @@ static irqreturn_t mmc_davinci_irq(int irq, void *dev_id) 
	if (qstatus & MMCST0_DATDNE) {

		/* All blocks sent/received, and CRC checks passed */

		if (data != NULL) {

			if ((host->do_dma == 0) && (host->bytes_left > 0)) {

			if (!host->do_dma) {

				if (host->bytes_left > 0)

					/* if datasize < rw_threshold

					 * no RX ints are generated

					 */

					davinci_fifo_data_trans(host, host->bytes_left);

				sg_miter_stop(&host->sg_miter);

			}

			end_transfer = 1;

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