On 01/30, Georgi Djakov wrote:
> @@ -75,17 +110,389 @@ struct sdhci_msm_host {
>  };
>  
>  /* MSM platform specific tuning */
> -int sdhci_msm_execute_tuning(struct sdhci_host *host, u32 opcode)
> +static inline int msm_dll_poll_ck_out_en(struct sdhci_host *host, u8 poll)
> +{
> +     u32 wait_cnt = 50;
> +     u8 ck_out_en = 0;

Looks like a useless assignment.

> +     struct mmc_host *mmc = host->mmc;
> +
> +     /* poll for CK_OUT_EN bit.  max. poll time = 50us */
> +     ck_out_en = !!(readl_relaxed(host->ioaddr + CORE_DLL_CONFIG) &
> +                     CORE_CK_OUT_EN);
> +
> +     while (ck_out_en != poll) {
> +             if (--wait_cnt == 0) {
> +                     dev_err(mmc_dev(mmc), "%s: CK_OUT_EN bit is not %d\n",
> +                            mmc_hostname(mmc), poll);
> +                     return -ETIMEDOUT;
> +             }
> +             udelay(1);
> +
> +             ck_out_en = !!(readl_relaxed(host->ioaddr + CORE_DLL_CONFIG) &
> +                             CORE_CK_OUT_EN);
> +     }
> +
> +     return 0;
> +}
> +
> +static int msm_config_cm_dll_phase(struct sdhci_host *host, u8 phase)
> +{
> +     int rc = 0;

Looks like a useless assignment.

> +     u8 grey_coded_phase_table[] = {
> +             0x0, 0x1, 0x3, 0x2, 0x6, 0x7, 0x5, 0x4,
> +             0xc, 0xd, 0xf, 0xe, 0xa, 0xb, 0x9, 0x8
> +     };

This could be static const?

> +     unsigned long flags;
> +     u32 config;
> +     struct mmc_host *mmc = host->mmc;
> +
> +     spin_lock_irqsave(&host->lock, flags);
> +
> +     config = readl_relaxed(host->ioaddr + CORE_DLL_CONFIG);
> +     config &= ~(CORE_CDR_EN | CORE_CK_OUT_EN);
> +     config |= (CORE_CDR_EXT_EN | CORE_DLL_EN);
> +     writel_relaxed(config, host->ioaddr + CORE_DLL_CONFIG);
> +
> +     /* Wait until CK_OUT_EN bit of DLL_CONFIG register becomes '0' */
> +     rc = msm_dll_poll_ck_out_en(host, 0);
> +     if (rc)
> +             goto err_out;
> +
> +     /*
> +      * Write the selected DLL clock output phase (0 ... 15)
> +      * to CDR_SELEXT bit field of DLL_CONFIG register.
> +      */
> +     writel_relaxed(((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
> +                      & ~(0xF << 20))
> +                     | (grey_coded_phase_table[phase] << 20)),
> +                    host->ioaddr + CORE_DLL_CONFIG);

Wow this is complicated. Can we please break this up into
multiple lines? What does 0xf << 20 mean?

> +
> +     /* Set CK_OUT_EN bit of DLL_CONFIG register to 1. */
> +     writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
> +                     | CORE_CK_OUT_EN), host->ioaddr + CORE_DLL_CONFIG);
> +
[...]
> +}
> +
> +static int msm_find_most_appropriate_phase(struct sdhci_host *host,
> +                                        u8 *phase_table, u8 total_phases)
> +{
[...]
> +
> +     for (cnt = 0; cnt <= row_index; cnt++) {
> +             if (phases_per_row[cnt] > curr_max) {
> +                     curr_max = phases_per_row[cnt];
> +                     selected_row_index = cnt;
> +             }
> +     }
> +
> +     i = ((curr_max * 3) / 4);

Unnecessary extra parentheses here.

> +     if (i)
> +             i--;
> +
> +     ret = (int)ranges[selected_row_index][i];

Is this cast necessary?

> +
> +     if (ret >= MAX_PHASES) {
> +             ret = -EINVAL;
> +             dev_err(mmc_dev(mmc), "%s: invalid phase selected=%d\n",
> +                    mmc_hostname(mmc), ret);
> +     }
> +
> +     return ret;
> +}
> +
> +static inline void msm_cm_dll_set_freq(struct sdhci_host *host)
> +{
> +     u32 mclk_freq = 0;
> +
> +     /* Program the MCLK value to MCLK_FREQ bit field */
> +     if (host->clock <= 112000000)
> +             mclk_freq = 0;
> +     else if (host->clock <= 125000000)
> +             mclk_freq = 1;
> +     else if (host->clock <= 137000000)
> +             mclk_freq = 2;
> +     else if (host->clock <= 150000000)
> +             mclk_freq = 3;
> +     else if (host->clock <= 162000000)
> +             mclk_freq = 4;
> +     else if (host->clock <= 175000000)
> +             mclk_freq = 5;
> +     else if (host->clock <= 187000000)
> +             mclk_freq = 6;
> +     else if (host->clock <= 200000000)
> +             mclk_freq = 7;

This could be a case statement but I'm not sure it's any clearer.
At least the range is specified.

        switch (host->clock) {
        case 0 ... 112000000:
                mclk_freq = 0;
                break;
        case 112000001 ...  125000000:
                mclk_freq = 1;
                break;
        ...

> +
> +     writel_relaxed(((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
> +                      & ~(7 << 24)) | (mclk_freq << 24)),
> +                    host->ioaddr + CORE_DLL_CONFIG);

This is also complicated. Can you split this up into multiple lines?

> +int sdhci_msm_execute_tuning(struct sdhci_host *host, u32 opcode)
> +{
[...]
> +     do {
> +             struct mmc_command cmd = { 0 };
> +             struct mmc_data data = { 0 };
> +             struct mmc_request mrq = {
> +                     .cmd = &cmd,
> +                     .data = &data
> +             };
> +             struct scatterlist sg;
> +
> +             /* set the phase in delay line hw block */
> +             rc = msm_config_cm_dll_phase(host, phase);
> +             if (rc)
> +                     goto out;
> +
> +             cmd.opcode = opcode;
> +             cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
> +
> +             data.blksz = size;
> +             data.blocks = 1;
> +             data.flags = MMC_DATA_READ;
> +             data.timeout_ns = 1000 * 1000 * 1000;   /* 1 sec */

NSEC_PER_SEC?

> +
> +             data.sg = &sg;
> +             data.sg_len = 1;
> +             sg_init_one(&sg, data_buf, sizeof(data_buf));
> +             memset(data_buf, 0, sizeof(data_buf));
> +             mmc_wait_for_req(mmc, &mrq);
> +
> +             if (!cmd.error && !data.error &&
> +                 !memcmp(data_buf, tuning_block_pattern, sizeof(data_buf))) {
> +                     /* tuning is successful at this tuning point */
> +                     tuned_phases[tuned_phase_cnt++] = phase;
> +                     dev_dbg(mmc_dev(mmc), "%s: found good phase = %d\n",
> +                              mmc_hostname(mmc), phase);
> +             }
> +     } while (++phase < 16);

++phase < ARRAY_SIZE(tuned_phases) ?

> +
> +     if (tuned_phase_cnt) {
> +             rc = msm_find_most_appropriate_phase(host, tuned_phases,
> +                                                  tuned_phase_cnt);
> +             if (rc < 0)
> +                     goto out;
> +             else
> +                     phase = (u8) rc;

Unnecessary cast?

> +
> +             /*
> +              * Finally set the selected phase in delay
> +              * line hw block.
> +              */
> +             rc = msm_config_cm_dll_phase(host, phase);
> +             if (rc)
> +                     goto out;
> +             dev_dbg(mmc_dev(mmc), "%s: setting the tuning phase to %d\n",
> +                      mmc_hostname(mmc), phase);
> +     } else {
> +             if (--tuning_seq_cnt)
> +                     goto retry;
> +             /* tuning failed */
> +             dev_dbg(mmc_dev(mmc), "%s: no tuning point found\n",
> +                    mmc_hostname(mmc));
> +             rc = -EIO;
> +     }
> +
> +out:
> +     kfree(data_buf);
> +     return rc;
> +}
> +
>  #define MAX_PROP_SIZE 32
>  static int sdhci_msm_dt_parse_vreg_info(struct device *dev,
>                       struct sdhci_msm_reg_data *vreg, const char *vreg_name)

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