sunxi_mmc_init_host() originated from Allwinner kernel sources. The magic numbers written to various registers was never documented. Add comments for values found in Allwinner user manuals. Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx> --- drivers/mmc/host/sunxi-mmc.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c index 83de82bceafc..cce5ca540857 100644 --- a/drivers/mmc/host/sunxi-mmc.c +++ b/drivers/mmc/host/sunxi-mmc.c @@ -284,16 +284,28 @@ static int sunxi_mmc_init_host(struct mmc_host *mmc) if (sunxi_mmc_reset_host(host)) return -EIO; + /* + * Burst 8 transfers, RX trigger level: 7, TX trigger level: 8 + * + * TODO: sun9i has a larger FIFO and supports higher trigger values + */ mmc_writel(host, REG_FTRGL, 0x20070008); + /* Maximum timeout value */ mmc_writel(host, REG_TMOUT, 0xffffffff); + /* Unmask SDIO interrupt if needed */ mmc_writel(host, REG_IMASK, host->sdio_imask); + /* Clear all pending interrupts */ mmc_writel(host, REG_RINTR, 0xffffffff); + /* Debug register? undocumented */ mmc_writel(host, REG_DBGC, 0xdeb); + /* Enable CEATA support */ mmc_writel(host, REG_FUNS, SDXC_CEATA_ON); + /* Set DMA descriptor list base address */ mmc_writel(host, REG_DLBA, host->sg_dma); rval = mmc_readl(host, REG_GCTRL); rval |= SDXC_INTERRUPT_ENABLE_BIT; + /* Undocumented, but found in Allwinner code */ rval &= ~SDXC_ACCESS_DONE_DIRECT; mmc_writel(host, REG_GCTRL, rval); -- 2.7.0.rc3 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
