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Date: Wed, 8 Mar 2023 10:21:51 +0100
From: Oleksij Rempel <o.rempel@...gutronix.de>
To: Bjorn Helgaas <helgaas@...nel.org>
Cc: Arnd Bergmann <arnd@...db.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
linux-kernel@...r.kernel.org, Bjorn Helgaas <bhelgaas@...gle.com>
Subject: Re: [PATCH] misc: alcor_pci: Use PCI core to manage ASPM instead of
open-coding
On Tue, Mar 07, 2023 at 04:19:28PM -0600, Bjorn Helgaas wrote:
> [Sorry, Greg, fat-fingered your address the first time at
> https://lore.kernel.org/all/20230307213816.886308-1-helgaas@kernel.org/]
>
> On Tue, Mar 07, 2023 at 03:38:16PM -0600, Bjorn Helgaas wrote:
> > From: Bjorn Helgaas <bhelgaas@...gle.com>
> >
> > "priv->ext_config_dev_aspm" was never set to a non-zero value. Therefore,
> > alcor_pci_aspm_ctrl(priv, 1) did nothing, and alcor_pci_aspm_ctrl(priv, 0)
> > always disabled ASPM in the device and the upstream bridge.
> >
> > The driver disabled ASPM in alcor_pci_probe() and alcor_resume(), so it's
> > possible the device doesn't work well when ASPM is enabled.
> >
> > Remove all the ASPM-related code and replace the alcor_pci_aspm_ctrl(0)
> > calls with pci_disable_link_state(pdev, PCIE_LINK_STATE_L0S |
> > PCIE_LINK_STATE_L1), which asks the PCI core to disable ASPM.
> >
> > Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
> > Cc: Oleksij Rempel <o.rempel@...gutronix.de>
Reviewed-by: Oleksij Rempel <o.rempel@...gutronix.de>
Thank you!
> > ---
> > drivers/misc/cardreader/alcor_pci.c | 144 +---------------------------
> > include/linux/alcor_pci.h | 7 --
> > 2 files changed, 4 insertions(+), 147 deletions(-)
> >
> > diff --git a/drivers/misc/cardreader/alcor_pci.c b/drivers/misc/cardreader/alcor_pci.c
> > index 9080f9f150a2..5b637171c46c 100644
> > --- a/drivers/misc/cardreader/alcor_pci.c
> > +++ b/drivers/misc/cardreader/alcor_pci.c
> > @@ -95,137 +95,6 @@ u32 alcor_read32be(struct alcor_pci_priv *priv, unsigned int addr)
> > }
> > EXPORT_SYMBOL_GPL(alcor_read32be);
> >
> > -static int alcor_pci_find_cap_offset(struct alcor_pci_priv *priv,
> > - struct pci_dev *pci)
> > -{
> > - int where;
> > - u8 val8;
> > - u32 val32;
> > -
> > - where = ALCOR_CAP_START_OFFSET;
> > - pci_read_config_byte(pci, where, &val8);
> > - if (!val8)
> > - return 0;
> > -
> > - where = (int)val8;
> > - while (1) {
> > - pci_read_config_dword(pci, where, &val32);
> > - if (val32 == 0xffffffff) {
> > - dev_dbg(priv->dev, "find_cap_offset invalid value %x.\n",
> > - val32);
> > - return 0;
> > - }
> > -
> > - if ((val32 & 0xff) == 0x10) {
> > - dev_dbg(priv->dev, "pcie cap offset: %x\n", where);
> > - return where;
> > - }
> > -
> > - if ((val32 & 0xff00) == 0x00) {
> > - dev_dbg(priv->dev, "pci_find_cap_offset invalid value %x.\n",
> > - val32);
> > - break;
> > - }
> > - where = (int)((val32 >> 8) & 0xff);
> > - }
> > -
> > - return 0;
> > -}
> > -
> > -static void alcor_pci_init_check_aspm(struct alcor_pci_priv *priv)
> > -{
> > - struct pci_dev *pci;
> > - int where;
> > - u32 val32;
> > -
> > - priv->pdev_cap_off = alcor_pci_find_cap_offset(priv, priv->pdev);
> > - /*
> > - * A device might be attached to root complex directly and
> > - * priv->parent_pdev will be NULL. In this case we don't check its
> > - * capability and disable ASPM completely.
> > - */
> > - if (priv->parent_pdev)
> > - priv->parent_cap_off = alcor_pci_find_cap_offset(priv,
> > - priv->parent_pdev);
> > -
> > - if ((priv->pdev_cap_off == 0) || (priv->parent_cap_off == 0)) {
> > - dev_dbg(priv->dev, "pci_cap_off: %x, parent_cap_off: %x\n",
> > - priv->pdev_cap_off, priv->parent_cap_off);
> > - return;
> > - }
> > -
> > - /* link capability */
> > - pci = priv->pdev;
> > - where = priv->pdev_cap_off + ALCOR_PCIE_LINK_CAP_OFFSET;
> > - pci_read_config_dword(pci, where, &val32);
> > - priv->pdev_aspm_cap = (u8)(val32 >> 10) & 0x03;
> > -
> > - pci = priv->parent_pdev;
> > - where = priv->parent_cap_off + ALCOR_PCIE_LINK_CAP_OFFSET;
> > - pci_read_config_dword(pci, where, &val32);
> > - priv->parent_aspm_cap = (u8)(val32 >> 10) & 0x03;
> > -
> > - if (priv->pdev_aspm_cap != priv->parent_aspm_cap) {
> > - u8 aspm_cap;
> > -
> > - dev_dbg(priv->dev, "pdev_aspm_cap: %x, parent_aspm_cap: %x\n",
> > - priv->pdev_aspm_cap, priv->parent_aspm_cap);
> > - aspm_cap = priv->pdev_aspm_cap & priv->parent_aspm_cap;
> > - priv->pdev_aspm_cap = aspm_cap;
> > - priv->parent_aspm_cap = aspm_cap;
> > - }
> > -
> > - dev_dbg(priv->dev, "ext_config_dev_aspm: %x, pdev_aspm_cap: %x\n",
> > - priv->ext_config_dev_aspm, priv->pdev_aspm_cap);
> > - priv->ext_config_dev_aspm &= priv->pdev_aspm_cap;
> > -}
> > -
> > -static void alcor_pci_aspm_ctrl(struct alcor_pci_priv *priv, u8 aspm_enable)
> > -{
> > - struct pci_dev *pci;
> > - u8 aspm_ctrl, i;
> > - int where;
> > - u32 val32;
> > -
> > - if ((!priv->pdev_cap_off) || (!priv->parent_cap_off)) {
> > - dev_dbg(priv->dev, "pci_cap_off: %x, parent_cap_off: %x\n",
> > - priv->pdev_cap_off, priv->parent_cap_off);
> > - return;
> > - }
> > -
> > - if (!priv->pdev_aspm_cap)
> > - return;
> > -
> > - aspm_ctrl = 0;
> > - if (aspm_enable) {
> > - aspm_ctrl = priv->ext_config_dev_aspm;
> > -
> > - if (!aspm_ctrl) {
> > - dev_dbg(priv->dev, "aspm_ctrl == 0\n");
> > - return;
> > - }
> > - }
> > -
> > - for (i = 0; i < 2; i++) {
> > -
> > - if (i) {
> > - pci = priv->parent_pdev;
> > - where = priv->parent_cap_off
> > - + ALCOR_PCIE_LINK_CTRL_OFFSET;
> > - } else {
> > - pci = priv->pdev;
> > - where = priv->pdev_cap_off
> > - + ALCOR_PCIE_LINK_CTRL_OFFSET;
> > - }
> > -
> > - pci_read_config_dword(pci, where, &val32);
> > - val32 &= (~0x03);
> > - val32 |= (aspm_ctrl & priv->pdev_aspm_cap);
> > - pci_write_config_byte(pci, where, (u8)val32);
> > - }
> > -
> > -}
> > -
> > static inline void alcor_mask_sd_irqs(struct alcor_pci_priv *priv)
> > {
> > alcor_write32(priv, 0, AU6601_REG_INT_ENABLE);
> > @@ -308,7 +177,6 @@ static int alcor_pci_probe(struct pci_dev *pdev,
> >
> > pci_set_master(pdev);
> > pci_set_drvdata(pdev, priv);
> > - alcor_pci_init_check_aspm(priv);
> >
> > for (i = 0; i < ARRAY_SIZE(alcor_pci_cells); i++) {
> > alcor_pci_cells[i].platform_data = priv;
> > @@ -319,7 +187,7 @@ static int alcor_pci_probe(struct pci_dev *pdev,
> > if (ret < 0)
> > goto error_clear_drvdata;
> >
> > - alcor_pci_aspm_ctrl(priv, 0);
> > + pci_disable_link_state(pdev, PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1);
> >
> > return 0;
> >
> > @@ -339,8 +207,6 @@ static void alcor_pci_remove(struct pci_dev *pdev)
> >
> > priv = pci_get_drvdata(pdev);
> >
> > - alcor_pci_aspm_ctrl(priv, 1);
> > -
> > mfd_remove_devices(&pdev->dev);
> >
> > ida_free(&alcor_pci_idr, priv->id);
> > @@ -353,18 +219,16 @@ static void alcor_pci_remove(struct pci_dev *pdev)
> > #ifdef CONFIG_PM_SLEEP
> > static int alcor_suspend(struct device *dev)
> > {
> > - struct alcor_pci_priv *priv = dev_get_drvdata(dev);
> > -
> > - alcor_pci_aspm_ctrl(priv, 1);
> > return 0;
> > }
> >
> > static int alcor_resume(struct device *dev)
> > {
> > -
> > struct alcor_pci_priv *priv = dev_get_drvdata(dev);
> >
> > - alcor_pci_aspm_ctrl(priv, 0);
> > + pci_disable_link_state(priv->pdev,
> > + PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1);
> > +
> > return 0;
> > }
> > #endif /* CONFIG_PM_SLEEP */
> > diff --git a/include/linux/alcor_pci.h b/include/linux/alcor_pci.h
> > index 8274ed525e9f..c4a0b23846d8 100644
> > --- a/include/linux/alcor_pci.h
> > +++ b/include/linux/alcor_pci.h
> > @@ -268,13 +268,6 @@ struct alcor_pci_priv {
> > unsigned long id; /* idr id */
> >
> > struct alcor_dev_cfg *cfg;
> > -
> > - /* PCI ASPM related vars */
> > - int pdev_cap_off;
> > - u8 pdev_aspm_cap;
> > - int parent_cap_off;
> > - u8 parent_aspm_cap;
> > - u8 ext_config_dev_aspm;
> > };
> >
> > void alcor_write8(struct alcor_pci_priv *priv, u8 val, unsigned int addr);
> > --
> > 2.25.1
> >
>
--
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