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Commit 86ee26f5 authored by Wolfgang Muees's avatar Wolfgang Muees Committed by Linus Torvalds
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mmc: at91_mci: use DMA buffer for read 



Convert the read to use the DMA buffer as well.  The old code was doing
double-buffering DMA with the PDC; no way to make it work.  Replace it
with a single-PDC approach.  It also simplify things removing the need for
a pre_dma_read() function.

[nicolas.ferre@atmel.com coding style modifications]
Signed-off-by: default avatarWolfgang Muees <wolfgang.mues@auerswald.de>
Signed-off-by: default avatarNicolas Ferre <nicolas.ferre@atmel.com>
Cc: Andrew Victor <avictor.za@gmail.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3780d906

drivers/mmc/host/at91_mci.c

+32 −96
Original line number Diff line number Diff line
@@ -250,74 +250,6 @@ static inline void at91_mci_sg_to_dma(struct at91mci_host *host, struct mmc_data 
	BUG_ON(size != 0);

}



/*

 * Prepare a dma read

 */

static void at91_mci_pre_dma_read(struct at91mci_host *host)

{

	int i;

	struct scatterlist *sg;

	struct mmc_command *cmd;

	struct mmc_data *data;



	pr_debug("pre dma read\n");



	cmd = host->cmd;

	if (!cmd) {

		pr_debug("no command\n");

		return;

	}



	data = cmd->data;

	if (!data) {

		pr_debug("no data\n");

		return;

	}



	for (i = 0; i < 2; i++) {

		/* nothing left to transfer */

		if (host->transfer_index >= data->sg_len) {

			pr_debug("Nothing left to transfer (index = %d)\n", host->transfer_index);

			break;

		}



		/* Check to see if this needs filling */

		if (i == 0) {

			if (at91_mci_read(host, ATMEL_PDC_RCR) != 0) {

				pr_debug("Transfer active in current\n");

				continue;

			}

		}

		else {

			if (at91_mci_read(host, ATMEL_PDC_RNCR) != 0) {

				pr_debug("Transfer active in next\n");

				continue;

			}

		}



		/* Setup the next transfer */

		pr_debug("Using transfer index %d\n", host->transfer_index);



		sg = &data->sg[host->transfer_index++];

		pr_debug("sg = %p\n", sg);



		sg->dma_address = dma_map_page(NULL, sg_page(sg), sg->offset, sg->length, DMA_FROM_DEVICE);



		pr_debug("dma address = %08X, length = %d\n", sg->dma_address, sg->length);



		if (i == 0) {

			at91_mci_write(host, ATMEL_PDC_RPR, sg->dma_address);

			at91_mci_write(host, ATMEL_PDC_RCR, (data->blksz & 0x3) ? sg->length : sg->length / 4);

		}

		else {

			at91_mci_write(host, ATMEL_PDC_RNPR, sg->dma_address);

			at91_mci_write(host, ATMEL_PDC_RNCR, (data->blksz & 0x3) ? sg->length : sg->length / 4);

		}

	}



	pr_debug("pre dma read done\n");

}



/*

 * Handle after a dma read

 */
@@ -325,6 +257,8 @@ static void at91_mci_post_dma_read(struct at91mci_host *host) 
{

	struct mmc_command *cmd;

	struct mmc_data *data;

	unsigned int len, i, size;

	unsigned *dmabuf = host->buffer;



	pr_debug("post dma read\n");
@@ -340,42 +274,39 @@ static void at91_mci_post_dma_read(struct at91mci_host *host) 
		return;

	}



	while (host->in_use_index < host->transfer_index) {

		struct scatterlist *sg;

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

	len = data->sg_len;



		pr_debug("finishing index %d\n", host->in_use_index);

	at91_mci_write(host, AT91_MCI_IDR, AT91_MCI_ENDRX);

	at91_mci_write(host, AT91_MCI_IER, AT91_MCI_RXBUFF);



		sg = &data->sg[host->in_use_index++];

	for (i = 0; i < len; i++) {

		struct scatterlist *sg;

		int amount;

		unsigned int *sgbuffer;



		pr_debug("Unmapping page %08X\n", sg->dma_address);

		sg = &data->sg[i];



		dma_unmap_page(NULL, sg->dma_address, sg->length, DMA_FROM_DEVICE);

		sgbuffer = kmap_atomic(sg_page(sg), KM_BIO_SRC_IRQ) + sg->offset;

		amount = min(size, sg->length);

		size -= amount;



		if (cpu_is_at91rm9200()) {	/* AT91RM9200 errata */

			unsigned int *buffer;

			int index;



			/* Swap the contents of the buffer */

			buffer = kmap_atomic(sg_page(sg), KM_BIO_SRC_IRQ) + sg->offset;

			pr_debug("buffer = %p, length = %d\n", buffer, sg->length);



			for (index = 0; index < (sg->length / 4); index++)

				buffer[index] = swab32(buffer[index]);



			kunmap_atomic(buffer, KM_BIO_SRC_IRQ);

		}



		flush_dcache_page(sg_page(sg));



		data->bytes_xfered += sg->length;

			for (index = 0; index < (amount / 4); index++)

				sgbuffer[index] = swab32(*dmabuf++);

		} else {

			char *tmpv = (char *)dmabuf;

			memcpy(sgbuffer, tmpv, amount);

			tmpv += amount;

			dmabuf = (unsigned *)tmpv;

		}



	/* Is there another transfer to trigger? */

	if (host->transfer_index < data->sg_len)

		at91_mci_pre_dma_read(host);

	else {

		at91_mci_write(host, AT91_MCI_IDR, AT91_MCI_ENDRX);

		at91_mci_write(host, AT91_MCI_IER, AT91_MCI_RXBUFF);

		kunmap_atomic(((void *)sgbuffer)-sg->offset, KM_BIO_SRC_IRQ);

		dmac_flush_range((void *)sgbuffer, ((void *)sgbuffer) + amount);

		data->bytes_xfered += amount;

		if (size == 0)

			break;

	}



	pr_debug("post dma read done\n");
@@ -610,7 +541,12 @@ static void at91_mci_send_command(struct at91mci_host *host, struct mmc_command 
				 */

				host->total_length = 0;



				at91_mci_pre_dma_read(host);

				at91_mci_write(host, ATMEL_PDC_RPR, host->physical_address);

				at91_mci_write(host, ATMEL_PDC_RCR, (data->blksz & 0x3) ?

					(blocks * block_length) : (blocks * block_length) / 4);

				at91_mci_write(host, ATMEL_PDC_RNPR, 0);

				at91_mci_write(host, ATMEL_PDC_RNCR, 0);



				ier = AT91_MCI_ENDRX /* | AT91_MCI_RXBUFF */;

			}

			else {