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Message-ID: <CACT4zj9Gkhpvtqfp19rBteZSdwcbArE8cOYmRYt7AgrsAabSxw@mail.gmail.com> Date: Wed, 2 Mar 2022 20:02:54 +0800 From: Ben Chuang <benchuanggli@...il.com> To: Ulf Hansson <ulf.hansson@...aro.org> Cc: Adrian Hunter <adrian.hunter@...el.com>, linux-mmc <linux-mmc@...r.kernel.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, greg.tu@...esyslogic.com.tw, Ben Chuang <ben.chuang@...esyslogic.com.tw>, SeanHY.Chen@...esyslogic.com.tw, Kevin Chang <kevin.chang@...uturecenter.com> Subject: Re: [PATCH] mmc: sdhci-pci-gli: Add runtime PM for GL9763E Hi, On Wed, Mar 2, 2022 at 6:04 PM Ulf Hansson <ulf.hansson@...aro.org> wrote: > > On Wed, 2 Mar 2022 at 03:10, Ben Chuang <benchuanggli@...il.com> wrote: > > > > Hi, > > > > On Tue, Mar 1, 2022 at 6:05 PM Adrian Hunter <adrian.hunter@...el.com> wrote: > > > > > > On 28/02/2022 19:03, Ulf Hansson wrote: > > > > On Fri, 25 Feb 2022 at 13:56, Ben Chuang <benchuanggli@...il.com> wrote: > > > >> > > > >> From: Ben Chuang <ben.chuang@...esyslogic.com.tw> > > > >> > > > >> 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@...esyslogic.com.tw> > > > >> Tested-by: Kevin Chang <kevin.chang@...uturecenter.com> > > > >> --- > > > >> 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. > I want to explain a little more, gl9763e is used as a boot disk controller. In gl9763e_runtime_suspend(), gl9763e still needs the internal clock to keep states. So gl9763e_runtime_suspend() only clears SDHCI_CLOCK_PLL_EN and SDHCI_CLOCK_CARD_EN. The SDHCI_CLOCK_INT_EN is still one (1) In runtime suspend, If using sdhci_enable_clk() in gl9763e_runtime_resume(), sdhci_enable_clk() only fills one (1) to this bit (SDHCI_CLOCK_INT_EN) again, it cannot cause internal stable bit (SDHCI_CLOCK_INT_STABLE) to one for gl9763e in the first while loop. > > > > > > 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 Best regards, Ben
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