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

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Date:   Thu, 5 Sep 2019 09:26:04 +0800
From:   Ben Chuang <benchuanggli@...il.com>
To:     Adrian Hunter <adrian.hunter@...el.com>
Cc:     Andy Shevchenko <andy.shevchenko@...il.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        linux-mmc <linux-mmc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "Michael K. Johnson" <johnsonm@...lj.org>
Subject: Re: [PATCH V7 5/5] mmc: host: sdhci-pci: Add Genesys Logic GL975x support

On Wed, Sep 4, 2019 at 5:54 PM Adrian Hunter <adrian.hunter@...el.com> wrote:
>
> On 4/09/19 3:58 AM, Ben Chuang wrote:
> > On Tue, Sep 3, 2019 at 6:05 AM Andy Shevchenko
> > <andy.shevchenko@...il.com> wrote:
> >>
> >> 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
> >
> > Hi, Andy,
> >
> > Thank you for your comments to make the code better.
> > Waiting to see if Adrian has any other comments.
>
> Nope! :-)
>
> Please go ahead and address Andy's comments.

OK, refine the code and let it better.