From 492d3223b076a9705b64897a061b60720f50d18b Mon Sep 17 00:00:00 2001 From: Stefan Roese Date: Mon, 29 Jun 2015 14:58:09 +0200 Subject: [PATCH] mmc: sdhci.c: Add config option to use a fixed buffer for transfers While implementing SDIO/MMC SPL booting for the Marvell Armada 38x, the following problem occured. The SPL runs in internal SRAM which is the L2 cache locked to memory. When the MMC buffers now are located on the stack (or bss), the SDIO controller (SDHCI) can't write into this L2 cache memory. This patch introduces a method to use a fixed buffer that will be used for all transfers by defining CONFIG_FIXED_SDHCI_ALIGNED_BUFFER. This way, the board can use this buffer address located in SDRAM for all transfers. This solves this SPL problem on the A38x and should only be used in the SPL U-Boot version. Tested for SPL booting on Marvell Armada 38x DB-88F6820-GP board. Signed-off-by: Stefan Roese Cc: Pantelis Antoniou Cc: Luka Perkov --- drivers/mmc/sdhci.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c index f72536b2aa..d89e302841 100644 --- a/drivers/mmc/sdhci.c +++ b/drivers/mmc/sdhci.c @@ -13,7 +13,11 @@ #include #include +#if defined(CONFIG_FIXED_SDHCI_ALIGNED_BUFFER) +void *aligned_buffer = (void *)CONFIG_FIXED_SDHCI_ALIGNED_BUFFER; +#else void *aligned_buffer; +#endif static void sdhci_reset(struct sdhci_host *host, u8 mask) { @@ -205,6 +209,17 @@ static int sdhci_send_command(struct mmc *mmc, struct mmc_cmd *cmd, memcpy(aligned_buffer, data->src, trans_bytes); } +#if defined(CONFIG_FIXED_SDHCI_ALIGNED_BUFFER) + /* + * Always use this bounce-buffer when + * CONFIG_FIXED_SDHCI_ALIGNED_BUFFER is defined + */ + is_aligned = 0; + start_addr = (unsigned long)aligned_buffer; + if (data->flags != MMC_DATA_READ) + memcpy(aligned_buffer, data->src, trans_bytes); +#endif + sdhci_writel(host, start_addr, SDHCI_DMA_ADDRESS); mode |= SDHCI_TRNS_DMA; #endif -- 2.39.5