From 3780d90602dfef6df3d8b39b203d6bf7fb99f22a Mon Sep 17 00:00:00 2001 From: Wolfgang Muees Date: Fri, 5 Mar 2010 13:43:40 -0800 Subject: [PATCH] mmc: at91_mci: use one coherent DMA buffer The TX DMA buffer is allocated only once, because the allocation/deallocation of the buffer for EACH chunk of data is time-consuming and prone to memory fragmentation. Using a coherent DMA buffer avoids extra data cache calls. [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 | 49 ++++++++++++++++++------------------- 1 file changed, 24 insertions(+), 25 deletions(-) diff --git a/drivers/mmc/host/at91_mci.c b/drivers/mmc/host/at91_mci.c index 37efe6b3f12d..76cb05ab9341 100644 --- a/drivers/mmc/host/at91_mci.c +++ b/drivers/mmc/host/at91_mci.c @@ -88,6 +88,10 @@ #define at91_mci_read(host, reg) __raw_readl((host)->baseaddr + (reg)) #define at91_mci_write(host, reg, val) __raw_writel((val), (host)->baseaddr + (reg)) +#define MCI_BLKSIZE 512 +#define MCI_MAXBLKSIZE 4095 +#define MCI_BLKATONCE 256 +#define MCI_BUFSIZE (MCI_BLKSIZE * MCI_BLKATONCE) /* * Low level type for this driver @@ -604,7 +608,6 @@ static void at91_mci_send_command(struct at91mci_host *host, struct mmc_command /* * Handle a read */ - host->buffer = NULL; host->total_length = 0; at91_mci_pre_dma_read(host); @@ -623,20 +626,8 @@ static void at91_mci_send_command(struct at91mci_host *host, struct mmc_command if (host->total_length < 12) host->total_length = 12; - host->buffer = kmalloc(host->total_length, GFP_KERNEL); - if (!host->buffer) { - pr_debug("Can't alloc tx buffer\n"); - cmd->error = -ENOMEM; - mmc_request_done(host->mmc, host->request); - return; - } - at91_mci_sg_to_dma(host, data); - host->physical_address = dma_map_single(NULL, - host->buffer, host->total_length, - DMA_TO_DEVICE); - pr_debug("Transmitting %d bytes\n", host->total_length); at91_mci_write(host, ATMEL_PDC_TPR, host->physical_address); @@ -703,14 +694,6 @@ static void at91_mci_completed_command(struct at91mci_host *host, unsigned int s cmd->resp[2] = at91_mci_read(host, AT91_MCI_RSPR(2)); cmd->resp[3] = at91_mci_read(host, AT91_MCI_RSPR(3)); - if (host->buffer) { - dma_unmap_single(NULL, - host->physical_address, host->total_length, - DMA_TO_DEVICE); - kfree(host->buffer); - host->buffer = NULL; - } - pr_debug("Status = %08X/%08x [%08X %08X %08X %08X]\n", status, at91_mci_read(host, AT91_MCI_SR), cmd->resp[0], cmd->resp[1], cmd->resp[2], cmd->resp[3]); @@ -1012,12 +995,12 @@ static int __init at91_mci_probe(struct platform_device *pdev) mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34; mmc->caps = MMC_CAP_SDIO_IRQ; - mmc->max_blk_size = 4095; - mmc->max_blk_count = mmc->max_req_size; + mmc->max_blk_size = MCI_MAXBLKSIZE; + mmc->max_blk_count = MCI_BLKATONCE; + mmc->max_req_size = MCI_BUFSIZE; host = mmc_priv(mmc); host->mmc = mmc; - host->buffer = NULL; host->bus_mode = 0; host->board = pdev->dev.platform_data; if (host->board->wire4) { @@ -1028,6 +1011,14 @@ static int __init at91_mci_probe(struct platform_device *pdev) " - using 1 wire\n"); } + host->buffer = dma_alloc_coherent(&pdev->dev, MCI_BUFSIZE, + &host->physical_address, GFP_KERNEL); + if (!host->buffer) { + ret = -ENOMEM; + dev_err(&pdev->dev, "Can't allocate transmit buffer\n"); + goto fail5; + } + /* * Reserve GPIOs ... board init code makes sure these pins are set * up as GPIOs with the right direction (input, except for vcc) @@ -1036,7 +1027,7 @@ static int __init at91_mci_probe(struct platform_device *pdev) ret = gpio_request(host->board->det_pin, "mmc_detect"); if (ret < 0) { dev_dbg(&pdev->dev, "couldn't claim card detect pin\n"); - goto fail5; + goto fail4b; } } if (host->board->wp_pin) { @@ -1136,6 +1127,10 @@ static int __init at91_mci_probe(struct platform_device *pdev) fail4: if (host->board->det_pin) gpio_free(host->board->det_pin); +fail4b: + if (host->buffer) + dma_free_coherent(&pdev->dev, MCI_BUFSIZE, + host->buffer, host->physical_address); fail5: mmc_free_host(mmc); fail6: @@ -1158,6 +1153,10 @@ static int __exit at91_mci_remove(struct platform_device *pdev) host = mmc_priv(mmc); + if (host->buffer) + dma_free_coherent(&pdev->dev, MCI_BUFSIZE, + host->buffer, host->physical_address); + if (host->board->det_pin) { if (device_can_wakeup(&pdev->dev)) free_irq(gpio_to_irq(host->board->det_pin), host);