From b86d825323b4c5d0c406e5b1a85af614acf0cf5a Mon Sep 17 00:00:00 2001 From: James Hogan Date: Fri, 24 Jun 2011 13:57:18 +0100 Subject: [PATCH] mmc: dw_mmc: don't hard code fifo depth, fix usage The FIFO_DEPTH hardware configuration parameter can be found from the power-on value of RX_WMark in the FIFOTH register. This is used to initialise the watermarks, but when calculating the number of free fifo spaces a preprocessor definition is used which is hard coded to 32. Fix reading the value out of FIFOTH (the default value in the RX_WMark field is FIFO_DEPTH-1 not FIFO_DEPTH). Allow the fifo depth to be overriden by platform data (since a bootloader may have changed FIFOTH making auto-detection unreliable). Store the fifo_depth for later use. Also fix the calculation to find the number of free bytes in the fifo to include the fifo depth in the left shift by the data shift, since the fifo depth is measured in fifo items not bytes. Signed-off-by: James Hogan Acked-by: Will Newton Signed-off-by: Chris Ball --- drivers/mmc/host/dw_mmc.c | 23 ++++++++++++++++++----- drivers/mmc/host/dw_mmc.h | 1 - include/linux/mmc/dw_mmc.h | 8 ++++++++ 3 files changed, 26 insertions(+), 6 deletions(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index 3f610d55f38e..3832312ce7cb 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -1116,8 +1116,8 @@ static void dw_mci_write_data_pio(struct dw_mci *host) unsigned int nbytes = 0, len; do { - len = SDMMC_FIFO_SZ - - (SDMMC_GET_FCNT(mci_readl(host, STATUS)) << shift); + len = (host->fifo_depth - + SDMMC_GET_FCNT(mci_readl(host, STATUS))) << shift; if (offset + len <= sg->length) { host->push_data(host, (void *)(buf + offset), len); @@ -1659,8 +1659,19 @@ static int dw_mci_probe(struct platform_device *pdev) * FIFO threshold settings RxMark = fifo_size / 2 - 1, * Tx Mark = fifo_size / 2 DMA Size = 8 */ - fifo_size = mci_readl(host, FIFOTH); - fifo_size = (fifo_size >> 16) & 0x7ff; + if (!host->pdata->fifo_depth) { + /* + * Power-on value of RX_WMark is FIFO_DEPTH-1, but this may + * have been overwritten by the bootloader, just like we're + * about to do, so if you know the value for your hardware, you + * should put it in the platform data. + */ + fifo_size = mci_readl(host, FIFOTH); + fifo_size = 1 + ((fifo_size >> 16) & 0x7ff); + } else { + fifo_size = host->pdata->fifo_depth; + } + host->fifo_depth = fifo_size; host->fifoth_val = ((0x2 << 28) | ((fifo_size/2 - 1) << 16) | ((fifo_size/2) << 0)); mci_writel(host, FIFOTH, host->fifoth_val); @@ -1707,7 +1718,9 @@ static int dw_mci_probe(struct platform_device *pdev) mci_writel(host, CTRL, SDMMC_CTRL_INT_ENABLE); /* Enable mci interrupt */ dev_info(&pdev->dev, "DW MMC controller at irq %d, " - "%d bit host data width\n", irq, width); + "%d bit host data width, " + "%u deep fifo\n", + irq, width, fifo_size); if (host->quirks & DW_MCI_QUIRK_IDMAC_DTO) dev_info(&pdev->dev, "Internal DMAC interrupt fix enabled.\n"); diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h index bb9e5de76ae9..027d37735394 100644 --- a/drivers/mmc/host/dw_mmc.h +++ b/drivers/mmc/host/dw_mmc.h @@ -118,7 +118,6 @@ #define SDMMC_CMD_INDX(n) ((n) & 0x1F) /* Status register defines */ #define SDMMC_GET_FCNT(x) (((x)>>17) & 0x1FF) -#define SDMMC_FIFO_SZ 32 /* Internal DMAC interrupt defines */ #define SDMMC_IDMAC_INT_AI BIT(9) #define SDMMC_IDMAC_INT_NI BIT(8) diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h index dea48475c436..01db1a0b3dd1 100644 --- a/include/linux/mmc/dw_mmc.h +++ b/include/linux/mmc/dw_mmc.h @@ -74,6 +74,7 @@ struct mmc_data; * @pdev: Platform device associated with the MMC controller. * @pdata: Platform data associated with the MMC controller. * @slot: Slots sharing this MMC controller. + * @fifo_depth: depth of FIFO. * @data_shift: log2 of FIFO item size. * @push_data: Pointer to FIFO push function. * @pull_data: Pointer to FIFO pull function. @@ -146,6 +147,7 @@ struct dw_mci { struct dw_mci_slot *slot[MAX_MCI_SLOTS]; /* FIFO push and pull */ + int fifo_depth; int data_shift; void (*push_data)(struct dw_mci *host, void *buf, int cnt); void (*pull_data)(struct dw_mci *host, void *buf, int cnt); @@ -196,6 +198,12 @@ struct dw_mci_board { unsigned int bus_hz; /* Bus speed */ unsigned int caps; /* Capabilities */ + /* + * Override fifo depth. If 0, autodetect it from the FIFOTH register, + * but note that this may not be reliable after a bootloader has used + * it. + */ + unsigned int fifo_depth; /* delay in mS before detecting cards after interrupt */ u32 detect_delay_ms; -- 2.20.1