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 <tgih.jun@xxxxxxxxxxx>
---
drivers/mmc/host/dw_mmc-exynos.c | 124 ++++++++++++++++++++++++++++++++++++++
1 files changed, 124 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
index 866edef..90f9335 100644
--- a/drivers/mmc/host/dw_mmc-exynos.c
+++ b/drivers/mmc/host/dw_mmc-exynos.c
@@ -14,8 +14,10 @@
#include <linux/clk.h>
#include <linux/mmc/host.h>
#include <linux/mmc/dw_mmc.h>
+#include <linux/mmc/mmc.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
+#include <linux/slab.h>
#include "dw_mmc.h"
#include "dw_mmc-pltfm.h"
@@ -150,6 +152,127 @@ 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 |
@@ -166,6 +289,7 @@ 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[] = {
--
1.7.0.4
--
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
