linux-kernel - Re: [PATCH V7 5/5] mmc: host: sdhci-pci: Add Genesys Logic GL975x support

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Message-ID: <CAHp75Vfx4FukybSjQjiNNQpHUNQrUsvwOen4ibqxOONKTJNxww@mail.gmail.com>
Date:   Tue, 3 Sep 2019 01:05:16 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Ben Chuang <benchuanggli@...il.com>
Cc:     Adrian Hunter <adrian.hunter@...el.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        linux-mmc <linux-mmc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        johnsonm@...lj.org, ben.chuang@...esyslogic.com.tw
Subject: Re: [PATCH V7 5/5] mmc: host: sdhci-pci: Add Genesys Logic GL975x support

On Fri, Aug 30, 2019 at 5:28 AM Ben Chuang <benchuanggli@...il.com> wrote:
>
> From: Ben Chuang <ben.chuang@...esyslogic.com.tw>
>
> Add support for the GL9750 and GL9755 chipsets.
>
> Enable v4 mode and wait 5ms after set 1.8V signal enable for GL9750/
> GL9755. Fix the value of SDHCI_MAX_CURRENT register and use the vendor
> tuning flow for GL9750.
>

> Signed-off-by: Ben Chuang <ben.chuang@...esyslogic.com.tw>

Usually last one for latest developer / submitter goes on.

> Co-developed-by: Michael K Johnson <johnsonm@...lj.org>
> Signed-off-by: Michael K Johnson <johnsonm@...lj.org>


> +#define GLI_MAX_TUNING_LOOP 40


> +static void gli_set_9750(struct sdhci_host *host)
> +{
> +       u32 driving_value = 0;
> +       u32 pll_value = 0;
> +       u32 sw_ctrl_value = 0;
> +       u32 misc_value = 0;
> +       u32 parameter_value = 0;
> +       u32 control_value = 0;

> +

Redundant blank line.

> +       u16 ctrl2 = 0;

Do you need these all assignments above?

> +       driving_value = sdhci_readl(host, SDHCI_GLI_9750_DRIVING);
> +       pll_value = sdhci_readl(host, SDHCI_GLI_9750_PLL);
> +       sw_ctrl_value = sdhci_readl(host, SDHCI_GLI_9750_SW_CTRL);
> +       misc_value = sdhci_readl(host, SDHCI_GLI_9750_MISC);
> +       parameter_value = sdhci_readl(host, SDHCI_GLI_9750_TUNING_PARAMETERS);
> +       control_value = sdhci_readl(host, SDHCI_GLI_9750_TUNING_CONTROL);



> +
> +       udelay(1);

This misses the answer to question why. Why this is needed and why
timeout is this long?

> +
> +       gl9750_wt_off(host);
> +}

> +static int __sdhci_execute_tuning_9750(struct sdhci_host *host, u32 opcode)
> +{
> +       int i;

> +       int rx_inv = 0;

Duplicate assignment.

> +
> +       for (rx_inv = 0; rx_inv < 2; rx_inv++) {

> +               if (rx_inv & 0x1)
> +                       gli_set_9750_rx_inv(host, true);
> +               else
> +                       gli_set_9750_rx_inv(host, false);

gli_set_...(host, !!rx_inv);

> +
> +               sdhci_start_tuning(host);
> +
> +               for (i = 0; i < GLI_MAX_TUNING_LOOP; i++) {
> +                       u16 ctrl;
> +
> +                       sdhci_send_tuning(host, opcode);
> +
> +                       if (!host->tuning_done) {

> +                               if (rx_inv == 1) {

It's an invariant to the loop. So, you may do this check after outter loop.

> +                                       pr_info("%s: Tuning timeout, falling back to fixed sampling clock\n",
> +                                               mmc_hostname(host->mmc));

> +                                       sdhci_abort_tuning(host, opcode);

It will also de-duplicates this call.

> +                                       return -ETIMEDOUT;
> +                               }
> +                               sdhci_abort_tuning(host, opcode);
> +                               break;
> +                       }

> +               }
> +       }
> +
> +       pr_info("%s: Tuning failed, falling back to fixed sampling clock\n",
> +               mmc_hostname(host->mmc));
> +       sdhci_reset_tuning(host);
> +       return -EAGAIN;
> +}

> +static void sdhci_gli_voltage_switch(struct sdhci_host *host)
> +{

Any comment why?

> +       usleep_range(5000, 5500);
> +}

> +static u32 sdhci_gl9750_readl(struct sdhci_host *host, int reg)
> +{
> +       u32 value;
> +
> +       value = readl(host->ioaddr + reg);

> +       if (unlikely(reg == SDHCI_MAX_CURRENT)) {
> +               if (!(value & 0xff))
> +                       value |= 0xc8;
> +       }

if (a) {
 if (b) {
   ...
 }
}

is the same as

if (a && b) {
 ...
}

> +       return value;
> +}

> +#define PCI_DEVICE_ID_GLI_9755         0x9755
> +#define PCI_DEVICE_ID_GLI_9750         0x9750

-- 
With Best Regards,
Andy Shevchenko