RE: [PATCH v5 2/2] misc: rtsx: Add power saving functions and fix driving parameter

吳昊澄 Ricky
2020-09-09T07:11:18Z

> -----Original Message-----
> From: Bjorn Helgaas [mailto:helgaas@kernel.org]
> Sent: Wednesday, September 09, 2020 6:29 AM
> To: 吳昊澄 Ricky
> Cc: arnd@arndb.de; gregkh@linuxfoundation.org; bhelgaas@google.com;
> ulf.hansson@linaro.org; rui_feng@realsil.com.cn; linux-kernel@vger.kernel.org;
> puranjay12@gmail.com; linux-pci@vger.kernel.org;
> vailbhavgupta40@gamail.com
> Subject: Re: [PATCH v5 2/2] misc: rtsx: Add power saving functions and fix driving
> parameter
>
> On Mon, Sep 07, 2020 at 06:07:31PM +0800, ricky_wu@realtek.com wrote:
> > From: Ricky Wu <ricky_wu@realtek.com>
> >
> > v4:
> > split power down flow and power saving function to two patch
> >
> > v5:
> > fix up modified change under the --- line
>
> Hehe, this came out *above* the "---" line :)
>
> > Add rts522a L1 sub-state support
> > Save more power on rts5227 rts5249 rts525a rts5260
> > Fix rts5260 driving parameter
> >
> > Signed-off-by: Ricky Wu <ricky_wu@realtek.com>
> > ---
> > drivers/misc/cardreader/rts5227.c | 112 +++++++++++++++++++++-
> > drivers/misc/cardreader/rts5249.c | 145
> ++++++++++++++++++++++++++++-
> > drivers/misc/cardreader/rts5260.c | 28 +++---
> > drivers/misc/cardreader/rtsx_pcr.h | 17 ++++
> > 4 files changed, 283 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/misc/cardreader/rts5227.c
> b/drivers/misc/cardreader/rts5227.c
> > index 747391e3fb5d..8859011672cb 100644
> > --- a/drivers/misc/cardreader/rts5227.c
> > +++ b/drivers/misc/cardreader/rts5227.c
> > @@ -72,15 +72,80 @@ static void rts5227_fetch_vendor_settings(struct
> rtsx_pcr *pcr)
> >
> > pci_read_config_dword(pdev, PCR_SETTING_REG2, &reg);
> > pcr_dbg(pcr, "Cfg 0x%x: 0x%x\n", PCR_SETTING_REG2, reg);
> > + if (rtsx_check_mmc_support(reg))
> > + pcr->extra_caps |= EXTRA_CAPS_NO_MMC;
> > pcr->sd30_drive_sel_3v3 = rtsx_reg_to_sd30_drive_sel_3v3(reg);
> > if (rtsx_reg_check_reverse_socket(reg))
> > pcr->flags |= PCR_REVERSE_SOCKET;
> > }
> >
> > +static void rts5227_init_from_cfg(struct rtsx_pcr *pcr)
> > +{
> > + struct pci_dev *pdev = pcr->pci;
> > + int l1ss;
> > + u32 lval;
> > + struct rtsx_cr_option *option = &pcr->option;
> > +
> > + l1ss = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_L1SS);
> > + if (!l1ss)
> > + return;
> > +
> > + pci_read_config_dword(pdev, l1ss + PCI_L1SS_CTL1, &lval);
>
> This looks a little problematic. PCI_L1SS_CTL1 is an architected
> register in the ASPM L1 PM Substates capability, and its value may
> change at runtime because drivers/pci/pcie/aspm.c manages it.
>
> It looks like the code below does device-specific configuration based
> on the current PCI_L1SS_CTL1 value. But what happens if aspm.c
> changes PCI_L1SS_CTL1 later?
>

We are going to make sure and set the best configuration on the current time,
if host change the capability later, it doesn't affect function, only affect a little power saving

> > + if (CHK_PCI_PID(pcr, 0x522A)) {
> > + if (0 == (lval & 0x0F))
> > + rtsx_pci_enable_oobs_polling(pcr);
> > + else
> > + rtsx_pci_disable_oobs_polling(pcr);
> > + }
> > +
> > + if (lval & PCI_L1SS_CTL1_ASPM_L1_1)
> > + rtsx_set_dev_flag(pcr, ASPM_L1_1_EN);
> > + else
> > + rtsx_clear_dev_flag(pcr, ASPM_L1_1_EN);
> > +
> > + if (lval & PCI_L1SS_CTL1_ASPM_L1_2)
> > + rtsx_set_dev_flag(pcr, ASPM_L1_2_EN);
> > + else
> > + rtsx_clear_dev_flag(pcr, ASPM_L1_2_EN);
> > +
> > + if (lval & PCI_L1SS_CTL1_PCIPM_L1_1)
> > + rtsx_set_dev_flag(pcr, PM_L1_1_EN);
> > + else
> > + rtsx_clear_dev_flag(pcr, PM_L1_1_EN);
> > +
> > + if (lval & PCI_L1SS_CTL1_PCIPM_L1_2)
> > + rtsx_set_dev_flag(pcr, PM_L1_2_EN);
> > + else
> > + rtsx_clear_dev_flag(pcr, PM_L1_2_EN);
> > +
> > + if (option->ltr_en) {
> > + u16 val;
> > +
> > + pcie_capability_read_word(pcr->pci, PCI_EXP_DEVCTL2, &val);
>
> Same thing here. I don't think the PCI core currently changes
> PCI_EXP_DEVCTL2 after boot, but it's not a good idea to assume it's
> going to be constant.
>

The same reply

> > + if (val & PCI_EXP_DEVCTL2_LTR_EN) {
> > + option->ltr_enabled = true;
> > + option->ltr_active = true;
> > + rtsx_set_ltr_latency(pcr, option->ltr_active_latency);
> > + } else {
> > + option->ltr_enabled = false;
> > + }
> > + }
> > +
> > + if (rtsx_check_dev_flag(pcr, ASPM_L1_1_EN | ASPM_L1_2_EN
> > + | PM_L1_1_EN | PM_L1_2_EN))
> > + option->force_clkreq_0 = false;
> > + else
> > + option->force_clkreq_0 = true;
> > +
> > +}
>
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