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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 <tgih.jun@samsung.com>
Tested-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Seungwon Jeon 2013-08-31 00:12:50 +09:00 committed by Chris Ball
parent 0976f16d2d
commit c537a1c5ff
1 changed files with 124 additions and 0 deletions
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124
drivers/mmc/host/dw_mmc-exynos.c
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@ -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"
@ -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[] = {