Commit 12658af5 authored by Linus Walleij's avatar Linus Walleij Committed by Ulf Hansson
Browse files

mmc: mxcmmc: 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.

Since this driver is using a worker, no atomic trickery
is needed.

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-v2-6-d8e732aa97d1@linaro.org


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 2761822c

drivers/mmc/host/mxcmmc.c

+33 −20
Original line number Diff line number Diff line
@@ -266,11 +266,18 @@ static inline void buffer_swap32(u32 *buf, int len) 


static void mxcmci_swap_buffers(struct mmc_data *data)

{

	struct scatterlist *sg;

	int i;

	struct sg_mapping_iter sgm;

	u32 *buf;



	for_each_sg(data->sg, sg, data->sg_len, i)

		buffer_swap32(sg_virt(sg), sg->length);

	sg_miter_start(&sgm, data->sg, data->sg_len,

		       SG_MITER_TO_SG | SG_MITER_FROM_SG);



	while (sg_miter_next(&sgm)) {

		buf = sgm.addr;

		buffer_swap32(buf, sgm.length);

	}



	sg_miter_stop(&sgm);

}

#else

static inline void mxcmci_swap_buffers(struct mmc_data *data) {}
@@ -526,10 +533,9 @@ static int mxcmci_poll_status(struct mxcmci_host *host, u32 mask) 
	} while (1);

}



static int mxcmci_pull(struct mxcmci_host *host, void *_buf, int bytes)

static int mxcmci_pull(struct mxcmci_host *host, u32 *buf, int bytes)

{

	unsigned int stat;

	u32 *buf = _buf;



	while (bytes > 3) {

		stat = mxcmci_poll_status(host,
@@ -555,10 +561,9 @@ static int mxcmci_pull(struct mxcmci_host *host, void *_buf, int bytes) 
	return 0;

}



static int mxcmci_push(struct mxcmci_host *host, void *_buf, int bytes)

static int mxcmci_push(struct mxcmci_host *host, u32 *buf, int bytes)

{

	unsigned int stat;

	u32 *buf = _buf;



	while (bytes > 3) {

		stat = mxcmci_poll_status(host, STATUS_BUF_WRITE_RDY);
@@ -586,31 +591,39 @@ static int mxcmci_push(struct mxcmci_host *host, void *_buf, int bytes) 
static int mxcmci_transfer_data(struct mxcmci_host *host)

{

	struct mmc_data *data = host->req->data;

	struct scatterlist *sg;

	int stat, i;

	struct sg_mapping_iter sgm;

	int stat;

	u32 *buf;



	host->data = data;

	host->datasize = 0;

	sg_miter_start(&sgm, data->sg, data->sg_len,

		       (data->flags & MMC_DATA_READ) ? SG_MITER_TO_SG : SG_MITER_FROM_SG);



	if (data->flags & MMC_DATA_READ) {

		for_each_sg(data->sg, sg, data->sg_len, i) {

			stat = mxcmci_pull(host, sg_virt(sg), sg->length);

		while (sg_miter_next(&sgm)) {

			buf = sgm.addr;

			stat = mxcmci_pull(host, buf, sgm.length);

			if (stat)

				return stat;

			host->datasize += sg->length;

				goto transfer_error;

			host->datasize += sgm.length;

		}

	} else {

		for_each_sg(data->sg, sg, data->sg_len, i) {

			stat = mxcmci_push(host, sg_virt(sg), sg->length);

		while (sg_miter_next(&sgm)) {

			buf = sgm.addr;

			stat = mxcmci_push(host, buf, sgm.length);

			if (stat)

				return stat;

			host->datasize += sg->length;

				goto transfer_error;

			host->datasize += sgm.length;

		}

		stat = mxcmci_poll_status(host, STATUS_WRITE_OP_DONE);

		if (stat)

			return stat;

			goto transfer_error;

	}

	return 0;



transfer_error:

	sg_miter_stop(&sgm);

	return stat;

}



static void mxcmci_datawork(struct work_struct *work)