Currently if a DMA buffer straddles a buffer alignment boundary (512KiB) then the DMA engine will pause and generate a DMA interrupt. Since the DMA interrupt is not enabled it will hang the MMC driver.
This patch adds support for restarting the DMA transfer. The SYSTEM_ADDRESS register contains the next address that would have been read/written when a boundary is hit. So we can read that and write it back. The write triggers the resumption of the transfer.
Signed-off-by: Anton Staaf robotboy@chromium.org Cc: Andy Fleming afleming@gmail.com Cc: Tom Warren twarren@nvidia.com Cc: Stephen Warren swarren@nvidia.com Cc: Albert Aribaud albert.u.boot@aribaud.net --- drivers/mmc/tegra2_mmc.c | 13 +++++++++++-- 1 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/tegra2_mmc.c b/drivers/mmc/tegra2_mmc.c index 2bea07d..159cef1 100644 --- a/drivers/mmc/tegra2_mmc.c +++ b/drivers/mmc/tegra2_mmc.c @@ -270,9 +270,16 @@ static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd, __func__, mask); return -1; } else if (mask & TEGRA_MMC_NORINTSTS_DMA_INTERRUPT) { - /* DMA Interrupt */ + /* + * DMA Interrupt, restart the transfer where + * it was interrupted. + */ + unsigned int address = readl(&host->reg->sysad); + debug("DMA end\n"); - break; + writel(TEGRA_MMC_NORINTSTS_DMA_INTERRUPT, + &host->reg->norintsts); + writel(address, &host->reg->sysad); } else if (mask & TEGRA_MMC_NORINTSTS_XFER_COMPLETE) { /* Transfer Complete */ debug("r/w is done\n"); @@ -419,6 +426,7 @@ static int mmc_core_init(struct mmc *mmc) * NORMAL Interrupt Status Enable Register init * [5] ENSTABUFRDRDY : Buffer Read Ready Status Enable * [4] ENSTABUFWTRDY : Buffer write Ready Status Enable + * [3] ENSTADMAINT : DMA boundary interrupt * [1] ENSTASTANSCMPLT : Transfre Complete Status Enable * [0] ENSTACMDCMPLT : Command Complete Status Enable */ @@ -426,6 +434,7 @@ static int mmc_core_init(struct mmc *mmc) mask &= ~(0xffff); mask |= (TEGRA_MMC_NORINTSTSEN_CMD_COMPLETE | TEGRA_MMC_NORINTSTSEN_XFER_COMPLETE | + TEGRA_MMC_NORINTSTSEN_DMA_INTERRUPT | TEGRA_MMC_NORINTSTSEN_BUFFER_WRITE_READY | TEGRA_MMC_NORINTSTSEN_BUFFER_READ_READY); writel(mask, &host->reg->norintstsen);