On Wed, 2 Mar 2022 at 03:10, Ben Chuang <benchuanggli@xxxxxxxxx> wrote:
>
> Hi,
>
> On Tue, Mar 1, 2022 at 6:05 PM Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> >
> > On 28/02/2022 19:03, Ulf Hansson wrote:
> > > On Fri, 25 Feb 2022 at 13:56, Ben Chuang <benchuanggli@xxxxxxxxx> wrote:
> > >>
> > >> From: Ben Chuang <ben.chuang@xxxxxxxxxxxxxxxxxxx>
> > >>
> > >> Add runtime PM for GL9763E and disable PLL in runtime suspend. So power
> > >> gated of upstream port can be enabled.
> > >>
> > >> Signed-off-by: Ben Chuang <ben.chuang@xxxxxxxxxxxxxxxxxxx>
> > >> Tested-by: Kevin Chang <kevin.chang@xxxxxxxxxxxxxxxxxx>
> > >> ---
> > >> drivers/mmc/host/sdhci-pci-gli.c | 54 ++++++++++++++++++++++++++++++++
> > >> 1 file changed, 54 insertions(+)
> > >>
> > >> diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
> > >> index 97035d77c18c..cf99b6af792d 100644
> > >> --- a/drivers/mmc/host/sdhci-pci-gli.c
> > >> +++ b/drivers/mmc/host/sdhci-pci-gli.c
> > >> @@ -873,6 +873,55 @@ static void gli_set_gl9763e(struct sdhci_pci_slot *slot)
> > >> pci_write_config_dword(pdev, PCIE_GLI_9763E_VHS, value);
> > >> }
> > >>
> > >> +#ifdef CONFIG_PM
> > >> +static int gl9763e_runtime_suspend(struct sdhci_pci_chip *chip)
> > >> +{
> > >> + struct sdhci_pci_slot *slot = chip->slots[0];
> > >> + struct sdhci_host *host = slot->host;
> > >> + u16 clock;
> > >> +
> > >> + clock = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
> > >> + clock &= ~(SDHCI_CLOCK_PLL_EN | SDHCI_CLOCK_CARD_EN);
> > >> + sdhci_writew(host, clock, SDHCI_CLOCK_CONTROL);
> > >> +
> > >> + return 0;
> > >> +}
> > >> +
> > >> +static int gl9763e_runtime_resume(struct sdhci_pci_chip *chip)
> > >> +{
> > >> + struct sdhci_pci_slot *slot = chip->slots[0];
> > >> + struct sdhci_host *host = slot->host;
> > >> + ktime_t timeout;
> > >> + u16 clock;
> > >> +
> > >> + clock = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
> > >> +
> > >> + clock |= SDHCI_CLOCK_PLL_EN;
> > >> + clock &= ~SDHCI_CLOCK_INT_STABLE;
> > >> + sdhci_writew(host, clock, SDHCI_CLOCK_CONTROL);
> > >> +
> > >> + timeout = ktime_add_ms(ktime_get(), 150);
> > >> + while (1) {
> > >> + bool timedout = ktime_after(ktime_get(), timeout);
> > >> +
> > >> + clock = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
> > >> + if (clock & SDHCI_CLOCK_INT_STABLE)
> > >> + break;
> > >> + if (timedout) {
> > >> + pr_err("%s: PLL clock never stabilised.\n",
> > >> + mmc_hostname(host->mmc));
> > >> + sdhci_dumpregs(host);
> > >> + break;
> > >> + }
> > >> + udelay(10);
> > >> + }
> >
> > Could use something like read_poll_timeout() here e.g.
> >
> > if (read_poll_timeout(sdhci_readw, clk, (clk & SDHCI_CLOCK_INT_STABLE),
> > 1000, 150000, false, host, SDHCI_CLOCK_CONTROL)) {
> > pr_err("%s: PLL clock never stabilised.\n",
> > mmc_hostname(host->mmc));
> > sdhci_dumpregs(host);
> > }
> >
> >
>
> Thanks for the tip. I will prepare the next patch.
>
> > >> + clock |= SDHCI_CLOCK_CARD_EN;
> > >> + sdhci_writew(host, clock, SDHCI_CLOCK_CONTROL);
> > >> +
> > >> + return 0;
> > >> +}
> > >
> > > Both functions above look very similar to what sdhci_set_clock() does.
> > > Can you use that, rather than open coding the above?
> > >
>
> The codes turn on/off the clock but it doesn't change the clock.
> Using sdhci_set_clock() needs to store the clock value because it
> clears the clock.
Well, in that case at least you can call sdhci_enable_clk() from
gl9763e_runtime_resume(), rather than open coding it (the code looks
like a direct copy of that code). All you need is to give the
sdhci_enable_clk() the correct "clk" as in-parameter.
>
> > > Other than that, I would appreciate it if Adrian could have a look at
> > > this too. For example, I wonder if perhaps
> > > sdhci_runtime_suspend|resume_host() should be called in these paths
> > > too.
> >
> > Assuming the host controller does not lose state information, it should be fine.
> >
>
> Yes, the host always has aux. power and keep state.
>
> Thank you both for your comments.
Okay, thanks for confirming!
[...]
Kind regards
Uffe
