From df953925a504d3c7a2a8814143a044c14d6660c0 Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 26 Jan 2016 13:41:14 +0000 Subject: [PATCH] mmc: sdhci: consolidate the DMA/ADMA size/address quicks Rather than scanning the scatterlist multiple times for each quirk, scan it once, checking for each possible quirk. This should be cheaper due to the length and offset members commonly sharing the same cache line than scanning the scatterlist multiple times. Signed-off-by: Russell King Signed-off-by: Adrian Hunter Tested-by: Gregory CLEMENT Signed-off-by: Ulf Hansson --- drivers/mmc/host/sdhci.c | 48 ++++++++++++++++-------------------------------- 1 file changed, 16 insertions(+), 32 deletions(-) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 5119904..2bd6bc1 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -731,22 +731,35 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd) /* * FIXME: This doesn't account for merging when mapping the * scatterlist. + * + * The assumption here being that alignment and lengths are + * the same after DMA mapping to device address space. */ if (host->flags & SDHCI_REQ_USE_DMA) { struct scatterlist *sg; - unsigned int length_mask; + unsigned int length_mask, offset_mask; int i; length_mask = 0; + offset_mask = 0; if (host->flags & SDHCI_USE_ADMA) { - if (host->quirks & SDHCI_QUIRK_32BIT_ADMA_SIZE) + if (host->quirks & SDHCI_QUIRK_32BIT_ADMA_SIZE) { length_mask = 3; + /* + * As we use up to 3 byte chunks to work + * around alignment problems, we need to + * check the offset as well. + */ + offset_mask = 3; + } } else { if (host->quirks & SDHCI_QUIRK_32BIT_DMA_SIZE) length_mask = 3; + if (host->quirks & SDHCI_QUIRK_32BIT_DMA_ADDR) + offset_mask = 3; } - if (unlikely(length_mask)) { + if (unlikely(length_mask | offset_mask)) { for_each_sg(data->sg, sg, data->sg_len, i) { if (sg->length & length_mask) { DBG("Reverting to PIO because of transfer size (%d)\n", @@ -754,35 +767,6 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd) host->flags &= ~SDHCI_REQ_USE_DMA; break; } - } - } - } - - /* - * The assumption here being that alignment is the same after - * translation to device address space. - */ - if (host->flags & SDHCI_REQ_USE_DMA) { - struct scatterlist *sg; - unsigned int offset_mask; - int i; - - offset_mask = 0; - if (host->flags & SDHCI_USE_ADMA) { - /* - * As we use 3 byte chunks to work around - * alignment problems, we need to check this - * quirk. - */ - if (host->quirks & SDHCI_QUIRK_32BIT_ADMA_SIZE) - offset_mask = 3; - } else { - if (host->quirks & SDHCI_QUIRK_32BIT_DMA_ADDR) - offset_mask = 3; - } - - if (unlikely(offset_mask)) { - for_each_sg(data->sg, sg, data->sg_len, i) { if (sg->offset & offset_mask) { DBG("Reverting to PIO because of bad alignment\n"); host->flags &= ~SDHCI_REQ_USE_DMA; -- 2.7.4