From 86ee26f5b0a889bf7e9f6351bbf01516d0686461 Mon Sep 17 00:00:00 2001 From: Wolfgang Muees Date: Fri, 5 Mar 2010 13:43:41 -0800 Subject: [PATCH] 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: Wolfgang Muees Signed-off-by: Nicolas Ferre Cc: Andrew Victor Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/mmc/host/at91_mci.c | 128 +++++++++--------------------------- 1 file changed, 32 insertions(+), 96 deletions(-) diff --git a/drivers/mmc/host/at91_mci.c b/drivers/mmc/host/at91_mci.c index 76cb05ab9341..818b4e75708a 100644 --- a/drivers/mmc/host/at91_mci.c +++ b/drivers/mmc/host/at91_mci.c @@ -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); + 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; } - flush_dcache_page(sg_page(sg)); - - data->bytes_xfered += sg->length; - } - - /* 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 { -- 2.20.1