diff options
| author | Chen-Yu Tsai <wens@csie.org> | 2016-01-21 08:26:28 +0300 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2016-02-29 13:02:50 +0300 |
| commit | 0314cbd438d7b9c079c4daafbdf09e788df03be8 (patch) | |
| tree | 934d28faadbff0cf19f76f8925b9f1156b919fdf /drivers | |
| parent | 9f24b0f2542f60bde7b699469a97cd852e1eed79 (diff) | |
| download | linux-0314cbd438d7b9c079c4daafbdf09e788df03be8.tar.xz | |
mmc: sunxi: Document host init sequence
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@csie.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/mmc/host/sunxi-mmc.c | 12 |
1 files changed, 12 insertions, 0 deletions
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); |