Re: [PATCH v1 1/2] mmc: mediatek: add support for 64-steps tuning

From: Chaotian Jing (井朝天)
Date: Tue Nov 28 2023 - 20:39:36 EST

Next message: Jacky Huang: "Re: [PATCH v2 3/4] arm64: dts: nuvoton: Add pinctrl support for ma35d1"
Previous message: Sean Christopherson: "Re: [RFC] x86/kvm/emulate: Avoid RET for fastops"
In reply to: Axe Yang: "[PATCH v1 1/2] mmc: mediatek: add support for 64-steps tuning"
Next in thread: Axe Yang: "[PATCH v1 2/2] dt-bindings: mmc: mtk-sd: add 64-steps tuning related property"
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On Fri, 2023-11-24 at 15:08 +0800, Axe Yang wrote:
> Previously, during the MSDC calibration process, a full clock cycle
> actually not be covered, which in some cases didn't yield the best
> results and could cause CRC errors. This problem is particularly
> evident when MSDC is used as an SDIO host. To solve this issue, the
> tuning step should be extended from 32 to 64. By using 64-steps
> tuning, a complete clock cycle can be covered.
>
> To illustrate, when tuning 32-steps, if the obtained window has a
> hole
> near the middle, like this: 0xffc07ff (hex), then the selected delay
> will be the 6 (counting from right to left).
>
> (32 <- 1)
> 1111 1111 1100 0000 0000 0111 11(1)1 1111
>
> However, if we tune 64-steps, the window obtained may look like this:
> 0xfffffffffffc07ff. The final selected delay will be 44, which is
> safer as it is further away from the hole:
>
> (64 <- 1)
> 1111 ... (1)111 1111 1111 1111 1111 1100 0000 0000 0111 1111 1111
>
> In this case, delay 6 selected through 32-steps tuning is obviously
> not optimal, and this delay is closer to the hole, using it would
> easily cause CRC problems.
>
> You will need to add property "mediatek,tune-64-steps" in MSDC dts
> node to enable the feature.
>
> Signed-off-by: Axe Yang <axe.yang@xxxxxxxxxxxx>
> ---
> drivers/mmc/host/mtk-sd.c | 133 +++++++++++++++++++++++++++---------
> --
> 1 file changed, 97 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> index 97f7c3d4be6e..aa955240e441 100644
> --- a/drivers/mmc/host/mtk-sd.c
> +++ b/drivers/mmc/host/mtk-sd.c
> @@ -252,12 +252,16 @@
>
> #define MSDC_PAD_TUNE_DATWRDLY GENMASK(4, 0) /* RW
> */
> #define MSDC_PAD_TUNE_DATRRDLY GENMASK(12, 8) /* RW */
> +#define MSDC_PAD_TUNE_DATRRDLY2 GENMASK(12, 8) /* RW */
> #define MSDC_PAD_TUNE_CMDRDLY GENMASK(20, 16) /* RW */
> +#define MSDC_PAD_TUNE_CMDRDLY2 GENMASK(20, 16) /* RW */
> #define MSDC_PAD_TUNE_CMDRRDLY GENMASK(26, 22) /* RW */
> #define MSDC_PAD_TUNE_CLKTDLY GENMASK(31, 27) /* RW */
> #define MSDC_PAD_TUNE_RXDLYSEL BIT(15) /* RW */
> #define MSDC_PAD_TUNE_RD_SEL BIT(13) /* RW */
> #define MSDC_PAD_TUNE_CMD_SEL BIT(21) /* RW */
> +#define MSDC_PAD_TUNE_RD2_SEL BIT(13) /* RW */
> +#define MSDC_PAD_TUNE_CMD2_SEL BIT(21) /* RW */
>
> #define PAD_DS_TUNE_DLY_SEL BIT(0) /* RW */
> #define PAD_DS_TUNE_DLY1 GENMASK(6, 2) /* RW */
> @@ -325,7 +329,8 @@
>
> #define DEFAULT_DEBOUNCE (8) /* 8 cycles CD debounce */
>
> -#define PAD_DELAY_MAX 32 /* PAD delay cells */
> +#define PAD_DELAY_HALF 32 /* PAD delay cells */
> +#define PAD_DELAY_FULL 64
> /*----------------------------------------------------------------
> ----------*/
> /* Descriptor
> Structure */
> /*----------------------------------------------------------------
> ----------*/
> @@ -465,6 +470,7 @@ struct msdc_host {
> /* cmd response sample selection for
> HS400 */
> bool hs400_mode; /* current eMMC will run at hs400 mode */
> bool hs400_tuning; /* hs400 mode online tuning */
> + bool tune_64steps;
> bool internal_cd; /* Use internal card-detect logic */
> bool cqhci; /* support eMMC hw cmdq */
> struct msdc_save_para save_para; /* used when gate HCLK */
> @@ -1615,7 +1621,7 @@ static irqreturn_t msdc_cmdq_irq(struct
> msdc_host *host, u32 intsts)
> }
>
> if (cmd_err || dat_err) {
> - dev_err(host->dev, "cmd_err = %d, dat_err =%d, intsts =
> 0x%x",
> + dev_err(host->dev, "cmd_err = %d, dat_err = %d, intsts
> = 0x%x",
> cmd_err, dat_err, intsts);
> }
>
> @@ -1780,10 +1786,20 @@ static void msdc_init_hw(struct msdc_host
> *host)
> DATA_K_VALUE_SEL);
> sdr_set_bits(host->top_base + EMMC_TOP_CMD,
> PAD_CMD_RD_RXDLY_SEL);
> + if (host->tune_64steps) {
> + sdr_set_bits(host->top_base +
> EMMC_TOP_CONTROL,
> + PAD_DAT_RD_RXDLY2_SEL);
> + sdr_set_bits(host->top_base +
> EMMC_TOP_CMD,
> + PAD_CMD_RD_RXDLY2_SEL);
> + }
> } else {
> sdr_set_bits(host->base + tune_reg,
> MSDC_PAD_TUNE_RD_SEL |
> MSDC_PAD_TUNE_CMD_SEL);
> + if (host->tune_64steps)
> + sdr_set_bits(host->base + tune_reg + 4,
> + MSDC_PAD_TUNE_RD2_SEL |
> + MSDC_PAD_TUNE_CMD2_SEL);
> }
> } else {
> /* choose clock tune */
> @@ -1925,24 +1941,24 @@ static void msdc_ops_set_ios(struct mmc_host
> *mmc, struct mmc_ios *ios)
> msdc_set_mclk(host, ios->timing, ios->clock);
> }
>
> -static u32 test_delay_bit(u32 delay, u32 bit)
> +static u64 test_delay_bit(u64 delay, u32 bit)
> {
> - bit %= PAD_DELAY_MAX;
> + bit %= PAD_DELAY_FULL;
> return delay & BIT(bit);
Since you are testing > 32 bits, you should use BIT_ULL() to instead of
BIT().
> }
>
> -static int get_delay_len(u32 delay, u32 start_bit)
> +static int get_delay_len(u64 delay, u32 start_bit)
> {
> int i;
>
> - for (i = 0; i < (PAD_DELAY_MAX - start_bit); i++) {
> + for (i = 0; i < (PAD_DELAY_FULL - start_bit); i++) {
> if (test_delay_bit(delay, start_bit + i) == 0)
> return i;
> }
> - return PAD_DELAY_MAX - start_bit;
> + return PAD_DELAY_FULL - start_bit;
> }
>
> -static struct msdc_delay_phase get_best_delay(struct msdc_host
> *host, u32 delay)
> +static struct msdc_delay_phase get_best_delay(struct msdc_host
> *host, u64 delay)
> {
> int start = 0, len = 0;
> int start_final = 0, len_final = 0;
> @@ -1950,28 +1966,28 @@ static struct msdc_delay_phase
> get_best_delay(struct msdc_host *host, u32 delay)
> struct msdc_delay_phase delay_phase = { 0, };
>
> if (delay == 0) {
> - dev_err(host->dev, "phase error: [map:%x]\n", delay);
> + dev_err(host->dev, "phase error: [map:%llx]\n", delay);
> delay_phase.final_phase = final_phase;
> return delay_phase;
> }
>
> - while (start < PAD_DELAY_MAX) {
> + while (start < PAD_DELAY_FULL) {
> len = get_delay_len(delay, start);
> if (len_final < len) {
> start_final = start;
> len_final = len;
> }
> start += len ? len : 1;
> - if (len >= 12 && start_final < 4)
> + if (!upper_32_bits(delay) && len >= 12 && start_final <
> 4)
> break;
> }
>
> /* The rule is that to find the smallest delay cell */
> if (start_final == 0)
> - final_phase = (start_final + len_final / 3) %
> PAD_DELAY_MAX;
> + final_phase = (start_final + len_final / 3) %
> PAD_DELAY_FULL;
> else
> - final_phase = (start_final + len_final / 2) %
> PAD_DELAY_MAX;
> - dev_dbg(host->dev, "phase: [map:%x] [maxlen:%d] [final:%d]\n",
> + final_phase = (start_final + len_final / 2) %
> PAD_DELAY_FULL;
> + dev_dbg(host->dev, "phase: [map:%llx] [maxlen:%d]
> [final:%d]\n",
> delay, len_final, final_phase);
>
> delay_phase.maxlen = len_final;
> @@ -1984,24 +2000,62 @@ static inline void msdc_set_cmd_delay(struct
> msdc_host *host, u32 value)
> {
> u32 tune_reg = host->dev_comp->pad_tune_reg;
>
> - if (host->top_base)
> - sdr_set_field(host->top_base + EMMC_TOP_CMD,
> PAD_CMD_RXDLY,
> - value);
> - else
> - sdr_set_field(host->base + tune_reg,
> MSDC_PAD_TUNE_CMDRDLY,
> - value);
> + if (host->top_base) {
> + if (value < PAD_DELAY_HALF) {
> + sdr_set_field(host->top_base + EMMC_TOP_CMD,
> PAD_CMD_RXDLY,
> + value);
> + sdr_set_field(host->top_base + EMMC_TOP_CMD,
> PAD_CMD_RXDLY2,
> + 0);
> + } else {
> + sdr_set_field(host->top_base + EMMC_TOP_CMD,
> PAD_CMD_RXDLY,
> + PAD_DELAY_HALF - 1);
> + sdr_set_field(host->top_base + EMMC_TOP_CMD,
> PAD_CMD_RXDLY2,
> + value - PAD_DELAY_HALF);
> + }
> + } else {
> + if (value < PAD_DELAY_HALF) {
> + sdr_set_field(host->base + tune_reg,
> MSDC_PAD_TUNE_CMDRDLY,
> + value);
> + sdr_set_field(host->base + tune_reg + 4,
> MSDC_PAD_TUNE_CMDRDLY2,
> + 0);
> + } else {
> + sdr_set_field(host->base + tune_reg,
> MSDC_PAD_TUNE_CMDRDLY,
> + PAD_DELAY_HALF - 1);
> + sdr_set_field(host->base + tune_reg + 4,
> MSDC_PAD_TUNE_CMDRDLY2,
> + value - PAD_DELAY_HALF);
> + }
> + }
> }
>
> static inline void msdc_set_data_delay(struct msdc_host *host, u32
> value)
> {
> u32 tune_reg = host->dev_comp->pad_tune_reg;
>
> - if (host->top_base)
> - sdr_set_field(host->top_base + EMMC_TOP_CONTROL,
> - PAD_DAT_RD_RXDLY, value);
> - else
> - sdr_set_field(host->base + tune_reg,
> MSDC_PAD_TUNE_DATRRDLY,
> - value);
> + if (host->top_base) {
> + if (value < PAD_DELAY_HALF) {
> + sdr_set_field(host->top_base +
> EMMC_TOP_CONTROL,
> + PAD_DAT_RD_RXDLY, value);
> + sdr_set_field(host->top_base +
> EMMC_TOP_CONTROL,
> + PAD_DAT_RD_RXDLY2, 0);
> + } else {
> + sdr_set_field(host->top_base +
> EMMC_TOP_CONTROL,
> + PAD_DAT_RD_RXDLY, PAD_DELAY_HALF
> - 1);
> + sdr_set_field(host->top_base +
> EMMC_TOP_CONTROL,
> + PAD_DAT_RD_RXDLY2, value -
> PAD_DELAY_HALF);
> + }
> + } else {
> + if (value < PAD_DELAY_HALF) {
> + sdr_set_field(host->base + tune_reg,
> MSDC_PAD_TUNE_DATRRDLY,
> + value);
> + sdr_set_field(host->base + tune_reg + 4,
> MSDC_PAD_TUNE_DATRRDLY2,
> + 0);
> + } else {
> + sdr_set_field(host->base + tune_reg,
> MSDC_PAD_TUNE_DATRRDLY,
> + PAD_DELAY_HALF - 1);
> + sdr_set_field(host->base + tune_reg + 4,
> MSDC_PAD_TUNE_DATRRDLY2,
> + value - PAD_DELAY_HALF);
> + }
> + }
> }
>
> static int msdc_tune_response(struct mmc_host *mmc, u32 opcode)
> @@ -2023,7 +2077,7 @@ static int msdc_tune_response(struct mmc_host
> *mmc, u32 opcode)
> host->hs200_cmd_int_delay);
>
> sdr_clr_bits(host->base + MSDC_IOCON, MSDC_IOCON_RSPL);
> - for (i = 0 ; i < PAD_DELAY_MAX; i++) {
> + for (i = 0 ; i < PAD_DELAY_HALF; i++) {
> msdc_set_cmd_delay(host, i);
> /*
> * Using the same parameters, it may sometimes pass the
> test,
> @@ -2047,7 +2101,7 @@ static int msdc_tune_response(struct mmc_host
> *mmc, u32 opcode)
> goto skip_fall;
>
> sdr_set_bits(host->base + MSDC_IOCON, MSDC_IOCON_RSPL);
> - for (i = 0; i < PAD_DELAY_MAX; i++) {
> + for (i = 0; i < PAD_DELAY_HALF; i++) {
> msdc_set_cmd_delay(host, i);
> /*
> * Using the same parameters, it may sometimes pass the
> test,
> @@ -2082,7 +2136,7 @@ static int msdc_tune_response(struct mmc_host
> *mmc, u32 opcode)
> if (host->dev_comp->async_fifo || host->hs200_cmd_int_delay)
> goto skip_internal;
>
> - for (i = 0; i < PAD_DELAY_MAX; i++) {
> + for (i = 0; i < PAD_DELAY_HALF; i++) {
> sdr_set_field(host->base + tune_reg,
> MSDC_PAD_TUNE_CMDRRDLY, i);
> mmc_send_tuning(mmc, opcode, &cmd_err);
> @@ -2121,7 +2175,7 @@ static int hs400_tune_response(struct mmc_host
> *mmc, u32 opcode)
> sdr_clr_bits(host->base + MSDC_IOCON, MSDC_IOCON_RSPL);
> else
> sdr_set_bits(host->base + MSDC_IOCON, MSDC_IOCON_RSPL);
> - for (i = 0 ; i < PAD_DELAY_MAX; i++) {
> + for (i = 0 ; i < PAD_DELAY_HALF; i++) {
> sdr_set_field(host->base + PAD_CMD_TUNE,
> PAD_CMD_TUNE_RX_DLY3, i);
> /*
> @@ -2160,7 +2214,7 @@ static int msdc_tune_data(struct mmc_host *mmc,
> u32 opcode)
> host->latch_ck);
> sdr_clr_bits(host->base + MSDC_IOCON, MSDC_IOCON_DSPL);
> sdr_clr_bits(host->base + MSDC_IOCON, MSDC_IOCON_W_DSPL);
> - for (i = 0 ; i < PAD_DELAY_MAX; i++) {
> + for (i = 0 ; i < PAD_DELAY_HALF; i++) {
> msdc_set_data_delay(host, i);
> ret = mmc_send_tuning(mmc, opcode, NULL);
> if (!ret)
> @@ -2174,7 +2228,7 @@ static int msdc_tune_data(struct mmc_host *mmc,
> u32 opcode)
>
> sdr_set_bits(host->base + MSDC_IOCON, MSDC_IOCON_DSPL);
> sdr_set_bits(host->base + MSDC_IOCON, MSDC_IOCON_W_DSPL);
> - for (i = 0; i < PAD_DELAY_MAX; i++) {
> + for (i = 0; i < PAD_DELAY_HALF; i++) {
> msdc_set_data_delay(host, i);
> ret = mmc_send_tuning(mmc, opcode, NULL);
> if (!ret)
> @@ -2206,10 +2260,11 @@ static int msdc_tune_data(struct mmc_host
> *mmc, u32 opcode)
> static int msdc_tune_together(struct mmc_host *mmc, u32 opcode)
> {
> struct msdc_host *host = mmc_priv(mmc);
> - u32 rise_delay = 0, fall_delay = 0;
> + u64 rise_delay = 0, fall_delay = 0;
> struct msdc_delay_phase final_rise_delay, final_fall_delay = {
> 0,};
> u8 final_delay, final_maxlen;
> int i, ret;
> + int tune_steps = host->tune_64steps ? PAD_DELAY_FULL :
> PAD_DELAY_HALF;
>
> sdr_set_field(host->base + MSDC_PATCH_BIT,
> MSDC_INT_DAT_LATCH_CK_SEL,
> host->latch_ck);
> @@ -2217,7 +2272,7 @@ static int msdc_tune_together(struct mmc_host
> *mmc, u32 opcode)
> sdr_clr_bits(host->base + MSDC_IOCON, MSDC_IOCON_RSPL);
> sdr_clr_bits(host->base + MSDC_IOCON,
> MSDC_IOCON_DSPL | MSDC_IOCON_W_DSPL);
> - for (i = 0 ; i < PAD_DELAY_MAX; i++) {
> + for (i = 0 ; i < tune_steps; i++) {
> msdc_set_cmd_delay(host, i);
> msdc_set_data_delay(host, i);
> ret = mmc_send_tuning(mmc, opcode, NULL);
> @@ -2233,7 +2288,7 @@ static int msdc_tune_together(struct mmc_host
> *mmc, u32 opcode)
> sdr_set_bits(host->base + MSDC_IOCON, MSDC_IOCON_RSPL);
> sdr_set_bits(host->base + MSDC_IOCON,
> MSDC_IOCON_DSPL | MSDC_IOCON_W_DSPL);
> - for (i = 0; i < PAD_DELAY_MAX; i++) {
> + for (i = 0; i < tune_steps; i++) {
> msdc_set_cmd_delay(host, i);
> msdc_set_data_delay(host, i);
> ret = mmc_send_tuning(mmc, opcode, NULL);
> @@ -2346,7 +2401,7 @@ static int msdc_execute_hs400_tuning(struct
> mmc_host *mmc, struct mmc_card *card
> }
>
> host->hs400_tuning = true;
> - for (i = 0; i < PAD_DELAY_MAX; i++) {
> + for (i = 0; i < PAD_DELAY_HALF; i++) {
> if (host->top_base)
> sdr_set_field(host->top_base +
> EMMC50_PAD_DS_TUNE,
> PAD_DS_DLY1, i);
> @@ -2601,6 +2656,12 @@ static void msdc_of_property_parse(struct
> platform_device *pdev,
> else
> host->hs400_cmd_resp_sel_rising = false;
>
> + if (of_property_read_bool(pdev->dev.of_node,
> + "mediatek,tune-64-steps"))
> + host->tune_64steps = true;
> + else
> + host->tune_64steps = false;
> +
> if (of_property_read_bool(pdev->dev.of_node,
> "supports-cqe"))
> host->cqhci = true;

Next message: Jacky Huang: "Re: [PATCH v2 3/4] arm64: dts: nuvoton: Add pinctrl support for ma35d1"
Previous message: Sean Christopherson: "Re: [RFC] x86/kvm/emulate: Avoid RET for fastops"
In reply to: Axe Yang: "[PATCH v1 1/2] mmc: mediatek: add support for 64-steps tuning"
Next in thread: Axe Yang: "[PATCH v1 2/2] dt-bindings: mmc: mtk-sd: add 64-steps tuning related property"
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