From c537a1c5ff63d3553617a9ff80ef5ed1493028e2 Mon Sep 17 00:00:00 2001 From: Seungwon Jeon Date: Sat, 31 Aug 2013 00:12:50 +0900 Subject: [PATCH] mmc: dw_mmc: exynos: add variable delay tuning sequence Implements variable delay tuning. In this change, exynos host can determine the correct sampling point for the HS200 and SDR104 speed mode. Signed-off-by: Seungwon Jeon Tested-by: Alim Akhtar Signed-off-by: Chris Ball --- drivers/mmc/host/dw_mmc-exynos.c | 124 +++++++++++++++++++++++++++++++ 1 file changed, 124 insertions(+) diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c index 83405bd8ab4c..b86f51845230 100644 --- a/drivers/mmc/host/dw_mmc-exynos.c +++ b/drivers/mmc/host/dw_mmc-exynos.c @@ -14,8 +14,10 @@ #include #include #include +#include #include #include +#include #include "dw_mmc.h" #include "dw_mmc-pltfm.h" @@ -231,6 +233,127 @@ static int dw_mci_exynos_parse_dt(struct dw_mci *host) return 0; } +static inline u8 dw_mci_exynos_get_clksmpl(struct dw_mci *host) +{ + return SDMMC_CLKSEL_CCLK_SAMPLE(mci_readl(host, CLKSEL)); +} + +static inline void dw_mci_exynos_set_clksmpl(struct dw_mci *host, u8 sample) +{ + u32 clksel; + clksel = mci_readl(host, CLKSEL); + clksel = (clksel & ~0x7) | SDMMC_CLKSEL_CCLK_SAMPLE(sample); + mci_writel(host, CLKSEL, clksel); +} + +static inline u8 dw_mci_exynos_move_next_clksmpl(struct dw_mci *host) +{ + u32 clksel; + u8 sample; + + clksel = mci_readl(host, CLKSEL); + sample = (clksel + 1) & 0x7; + clksel = (clksel & ~0x7) | sample; + mci_writel(host, CLKSEL, clksel); + return sample; +} + +static s8 dw_mci_exynos_get_best_clksmpl(u8 candiates) +{ + const u8 iter = 8; + u8 __c; + s8 i, loc = -1; + + for (i = 0; i < iter; i++) { + __c = ror8(candiates, i); + if ((__c & 0xc7) == 0xc7) { + loc = i; + goto out; + } + } + + for (i = 0; i < iter; i++) { + __c = ror8(candiates, i); + if ((__c & 0x83) == 0x83) { + loc = i; + goto out; + } + } + +out: + return loc; +} + +static int dw_mci_exynos_execute_tuning(struct dw_mci_slot *slot, u32 opcode, + struct dw_mci_tuning_data *tuning_data) +{ + struct dw_mci *host = slot->host; + struct mmc_host *mmc = slot->mmc; + const u8 *blk_pattern = tuning_data->blk_pattern; + u8 *blk_test; + unsigned int blksz = tuning_data->blksz; + u8 start_smpl, smpl, candiates = 0; + s8 found = -1; + int ret = 0; + + blk_test = kmalloc(blksz, GFP_KERNEL); + if (!blk_test) + return -ENOMEM; + + start_smpl = dw_mci_exynos_get_clksmpl(host); + + do { + struct mmc_request mrq = {NULL}; + struct mmc_command cmd = {0}; + struct mmc_command stop = {0}; + struct mmc_data data = {0}; + struct scatterlist sg; + + cmd.opcode = opcode; + cmd.arg = 0; + cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC; + + stop.opcode = MMC_STOP_TRANSMISSION; + stop.arg = 0; + stop.flags = MMC_RSP_R1B | MMC_CMD_AC; + + data.blksz = blksz; + data.blocks = 1; + data.flags = MMC_DATA_READ; + data.sg = &sg; + data.sg_len = 1; + + sg_init_one(&sg, blk_test, blksz); + mrq.cmd = &cmd; + mrq.stop = &stop; + mrq.data = &data; + host->mrq = &mrq; + + mci_writel(host, TMOUT, ~0); + smpl = dw_mci_exynos_move_next_clksmpl(host); + + mmc_wait_for_req(mmc, &mrq); + + if (!cmd.error && !data.error) { + if (!memcmp(blk_pattern, blk_test, blksz)) + candiates |= (1 << smpl); + } else { + dev_dbg(host->dev, + "Tuning error: cmd.error:%d, data.error:%d\n", + cmd.error, data.error); + } + } while (start_smpl != smpl); + + found = dw_mci_exynos_get_best_clksmpl(candiates); + if (found >= 0) + dw_mci_exynos_set_clksmpl(host, found); + else + ret = -EIO; + + kfree(blk_test); + return ret; +} + /* Common capabilities of Exynos4/Exynos5 SoC */ static unsigned long exynos_dwmmc_caps[4] = { MMC_CAP_UHS_DDR50 | MMC_CAP_1_8V_DDR | @@ -247,6 +370,7 @@ static const struct dw_mci_drv_data exynos_drv_data = { .prepare_command = dw_mci_exynos_prepare_command, .set_ios = dw_mci_exynos_set_ios, .parse_dt = dw_mci_exynos_parse_dt, + .execute_tuning = dw_mci_exynos_execute_tuning, }; static const struct of_device_id dw_mci_exynos_match[] = { -- 2.30.2