Hi Stephen,

On 02/08/2014 05:23 AM, Stephen Boyd wrote:

On 01/30, Georgi Djakov wrote:

quoted

@@ -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.

Yes, thanks!

quoted

+	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.

Ok.

quoted

+	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?

Yes, indeed!

quoted

+	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?

Yes, sure! I will simplify it! Only bits 23:20 are used.

quoted

+
+	/* 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);
+

[...]

quoted

+}
+
+static int msm_find_most_appropriate_phase(struct sdhci_host *host,
+					   u8 *phase_table, u8 total_phases)
+{

[...]

quoted

+
+	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.

Thanks!

quoted

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

Is this cast necessary?

Not necessary. Will fix it!

quoted

+
+	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;
	...

It seems to be shorter with the ifs, so i prefer to keep it this way.

quoted

+
+	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?

Yes, sure!

quoted

+int sdhci_msm_execute_tuning(struct sdhci_host *host, u32 opcode)
+{

[...]

quoted

+	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?

Thanks!

quoted

+
+		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) ?

Thanks!

quoted

+
+	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?

Yes, thank you for the review!

BR,
Georgi