Re: [PATCH v3 2/2] mmc: mediatek: Add HS400 online tuning support

From: Ulf Hansson
Date: Tue Sep 14 2021 - 04:46:50 EST

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On Wed, 8 Sept 2021 at 03:32, Wenbin Mei <wenbin.mei@xxxxxxxxxxxx> wrote:
>
> Due to the influence of the corner IC and vcore voltage, for the stability
> of HS400 mode, we Add HS400 mode online tuning support for mediatek mmc
> host.

My apologies, but I am not familiar with what 'HS400 online tuning'
is? Can you please elaborate on this?

Is it specific for a Mediatek eMMC controller - or is a common eMMC
feature that is described in the eMMC spec?

>
> Signed-off-by: Wenbin Mei <wenbin.mei@xxxxxxxxxxxx>
> Reviewed-by: Chaotian Jing <chaotian.jing@xxxxxxxxxxxx>
> ---
> drivers/mmc/core/mmc.c | 8 +++
> drivers/mmc/host/mtk-sd.c | 118 +++++++++++++++++++++++++++++++++++++-
> include/linux/mmc/host.h | 3 +

Please split this patch into a core patch and a mtk-sd patch.

> 3 files changed, 127 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 838726b68ff3..0aa72acd8612 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1222,6 +1222,14 @@ static int mmc_select_hs400(struct mmc_card *card)
> mmc_set_timing(host, MMC_TIMING_MMC_HS400);
> mmc_set_bus_speed(card);
>
> + if (host->ops->execute_hs400_tuning) {
> + mmc_retune_disable(host);
> + err = host->ops->execute_hs400_tuning(host, card);
> + mmc_retune_enable(host);
> + if (err)
> + goto out_err;
> + }
> +
> if (host->ops->hs400_complete)
> host->ops->hs400_complete(host);
>
> diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> index 4dfc246c5f95..484f5c38bfaf 100644
> --- a/drivers/mmc/host/mtk-sd.c
> +++ b/drivers/mmc/host/mtk-sd.c
> @@ -258,6 +258,7 @@
> #define MSDC_PAD_TUNE_RD_SEL (0x1 << 13) /* RW */
> #define MSDC_PAD_TUNE_CMD_SEL (0x1 << 21) /* RW */
>
> +#define PAD_DS_TUNE_DLY_SEL (0x1 << 0) /* RW */
> #define PAD_DS_TUNE_DLY1 (0x1f << 2) /* RW */
> #define PAD_DS_TUNE_DLY2 (0x1f << 7) /* RW */
> #define PAD_DS_TUNE_DLY3 (0x1f << 12) /* RW */
> @@ -301,6 +302,11 @@
> #define PAD_CMD_RD_RXDLY_SEL (0x1 << 11) /* RW */
> #define PAD_CMD_TX_DLY (0x1f << 12) /* RW */
>
> +/* EMMC50_PAD_DS_TUNE mask */
> +#define PAD_DS_DLY_SEL (0x1 << 16) /* RW */
> +#define PAD_DS_DLY1 (0x1f << 10) /* RW */
> +#define PAD_DS_DLY3 (0x1f << 0) /* RW */
> +
> #define REQ_CMD_EIO (0x1 << 0)
> #define REQ_CMD_TMO (0x1 << 1)
> #define REQ_DAT_ERR (0x1 << 2)
> @@ -448,11 +454,13 @@ struct msdc_host {
> bool vqmmc_enabled;
> u32 latch_ck;
> u32 hs400_ds_delay;
> + u32 hs400_ds_dly3;
> u32 hs200_cmd_int_delay; /* cmd internal delay for HS200/SDR104 */
> u32 hs400_cmd_int_delay; /* cmd internal delay for HS400 */
> bool hs400_cmd_resp_sel_rising;
> /* cmd response sample selection for HS400 */
> bool hs400_mode; /* current eMMC will run at hs400 mode */
> + bool hs400_tuning; /* hs400 mode online tuning */
> bool internal_cd; /* Use internal card-detect logic */
> bool cqhci; /* support eMMC hw cmdq */
> struct msdc_save_para save_para; /* used when gate HCLK */
> @@ -1190,7 +1198,8 @@ static bool msdc_cmd_done(struct msdc_host *host, int events,
> if (!sbc_error && !(events & MSDC_INT_CMDRDY)) {
> if (events & MSDC_INT_CMDTMO ||
> (cmd->opcode != MMC_SEND_TUNING_BLOCK &&
> - cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200))
> + cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200 &&
> + !host->hs400_tuning))
> /*
> * should not clear fifo/interrupt as the tune data
> * may have alreay come when cmd19/cmd21 gets response
> @@ -1287,7 +1296,8 @@ static void msdc_cmd_next(struct msdc_host *host,
> if ((cmd->error &&
> !(cmd->error == -EILSEQ &&
> (cmd->opcode == MMC_SEND_TUNING_BLOCK ||
> - cmd->opcode == MMC_SEND_TUNING_BLOCK_HS200))) ||
> + cmd->opcode == MMC_SEND_TUNING_BLOCK_HS200 ||
> + host->hs400_tuning))) ||
> (mrq->sbc && mrq->sbc->error))
> msdc_request_done(host, mrq);
> else if (cmd == mrq->sbc)
> @@ -2251,6 +2261,106 @@ static int msdc_prepare_hs400_tuning(struct mmc_host *mmc, struct mmc_ios *ios)
> return 0;
> }
>
> +static int msdc_send_cxd_data(struct mmc_card *card, struct mmc_host *host)
> +{
> + struct mmc_request mrq = {};
> + struct mmc_command cmd = {};
> + struct mmc_data data = {};
> + unsigned int len = 512;
> + struct scatterlist sg;
> + u8 *ext_csd;
> +
> + ext_csd = kzalloc(len, GFP_KERNEL);
> + if (!ext_csd)
> + return -ENOMEM;
> +
> + mrq.cmd = &cmd;
> + mrq.data = &data;
> +
> + cmd.opcode = MMC_SEND_EXT_CSD;
> + cmd.arg = 0;
> + cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
> +
> + data.blksz = len;
> + data.blocks = 1;
> + data.flags = MMC_DATA_READ;
> + data.sg = &sg;
> + data.sg_len = 1;
> +
> + sg_init_one(&sg, ext_csd, len);
> + mmc_set_data_timeout(&data, card);
> + mmc_wait_for_req(host, &mrq);
> +
> + kfree(ext_csd);
> +
> + if (cmd.error)
> + return cmd.error;
> + if (data.error)
> + return data.error;
> +
> + return 0;

Why do we need to send a MMC_SEND_EXT_CSD command, exactly?

Why can't mmc_send_tuning() work here too? What does the eMMC spec
state about this?

> +}
> +
> +static int msdc_execute_hs400_tuning(struct mmc_host *mmc, struct mmc_card *card)
> +{
> + struct msdc_host *host = mmc_priv(mmc);
> + struct msdc_delay_phase dly1_delay;
> + u32 val, result_dly1 = 0;
> + int i, ret;
> +
> + if (host->top_base) {
> + sdr_set_bits(host->top_base + EMMC50_PAD_DS_TUNE,
> + PAD_DS_DLY_SEL);
> + if (host->hs400_ds_dly3)
> + sdr_set_field(host->top_base + EMMC50_PAD_DS_TUNE,
> + PAD_DS_DLY3, host->hs400_ds_dly3);
> + } else {
> + sdr_set_bits(host->base + PAD_DS_TUNE, PAD_DS_TUNE_DLY_SEL);
> + if (host->hs400_ds_dly3)
> + sdr_set_field(host->base + PAD_DS_TUNE,
> + PAD_DS_TUNE_DLY3, host->hs400_ds_dly3);
> + }
> +
> + host->hs400_tuning = true;
> + for (i = 0; i < PAD_DELAY_MAX; i++) {
> + if (host->top_base)
> + sdr_set_field(host->top_base + EMMC50_PAD_DS_TUNE,
> + PAD_DS_DLY1, i);
> + else
> + sdr_set_field(host->base + PAD_DS_TUNE,
> + PAD_DS_TUNE_DLY1, i);
> + ret = msdc_send_cxd_data(card, mmc);
> + if (!ret)
> + result_dly1 |= (1 << i);
> + }
> + host->hs400_tuning = false;
> +
> + dly1_delay = get_best_delay(host, result_dly1);
> + if (dly1_delay.maxlen == 0) {
> + dev_err(host->dev, "Failed to get DLY1 delay!\n");
> + goto fail;
> + }
> + if (host->top_base)
> + sdr_set_field(host->top_base + EMMC50_PAD_DS_TUNE,
> + PAD_DS_DLY1, dly1_delay.final_phase);
> + else
> + sdr_set_field(host->base + PAD_DS_TUNE,
> + PAD_DS_TUNE_DLY1, dly1_delay.final_phase);
> +
> + if (host->top_base)
> + val = readl(host->top_base + EMMC50_PAD_DS_TUNE);
> + else
> + val = readl(host->base + PAD_DS_TUNE);
> +
> + dev_info(host->dev, "Fianl PAD_DS_TUNE: 0x%x\n", val);
> +
> + return 0;
> +
> +fail:
> + dev_err(host->dev, "Failed to tuning DS pin delay!\n");
> + return -EIO;
> +}

[...]

Kind regards
Uffe

Next message: Jiasheng Jiang: "Re:Re:[PATCH 6/6] irq: Potentially 'offset out of size' bug"
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