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

Bjorn Helgaas
2020-09-08T22:28:41Z

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?

> + 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.

> + 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;
> +
> +}