linux-kernel - [RFC PATCH v1 08/13] e1000e: Remove unreliable pci_disable_link_state{,

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Message-Id: <20230602114751.19671-9-ilpo.jarvinen@linux.intel.com>
Date:   Fri,  2 Jun 2023 14:47:45 +0300
From:   Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To:     linux-pci@...r.kernel.org, Bjorn Helgaas <helgaas@...nel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Lukas Wunner <lukas@...ner.de>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Emmanuel Grumbach <emmanuel.grumbach@...el.com>,
        Jesse Brandeburg <jesse.brandeburg@...el.com>,
        Tony Nguyen <anthony.l.nguyen@...el.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Subject: [RFC PATCH v1 08/13] e1000e: Remove unreliable pci_disable_link_state{,_locked}() workaround

pci_disable_link_state() and pci_disable_link_state_locked() were made
reliable regardless of ASPM CONFIG and OS being disallowed to change
ASPM states to allow drivers to rely on them working.

Remove driver working around unreliable
pci_disable_link_state{,_locked}() from e1000e driver and just call the
functions directly.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
---
 drivers/net/ethernet/intel/e1000e/netdev.c | 77 +---------------------
 1 file changed, 2 insertions(+), 75 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index bd7ef59b1f2e..d680d059a681 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -6763,79 +6763,6 @@ static int __e1000_shutdown(struct pci_dev *pdev, bool runtime)
 	return 0;
 }
 
-/**
- * __e1000e_disable_aspm - Disable ASPM states
- * @pdev: pointer to PCI device struct
- * @state: bit-mask of ASPM states to disable
- * @locked: indication if this context holds pci_bus_sem locked.
- *
- * Some devices *must* have certain ASPM states disabled per hardware errata.
- **/
-static void __e1000e_disable_aspm(struct pci_dev *pdev, u16 state, int locked)
-{
-	struct pci_dev *parent = pdev->bus->self;
-	u16 aspm_dis_mask = 0;
-	u16 pdev_aspmc, parent_aspmc;
-
-	switch (state) {
-	case PCIE_LINK_STATE_L0S:
-	case PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1:
-		aspm_dis_mask |= PCI_EXP_LNKCTL_ASPM_L0S;
-		fallthrough; /* can't have L1 without L0s */
-	case PCIE_LINK_STATE_L1:
-		aspm_dis_mask |= PCI_EXP_LNKCTL_ASPM_L1;
-		break;
-	default:
-		return;
-	}
-
-	pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &pdev_aspmc);
-	pdev_aspmc &= PCI_EXP_LNKCTL_ASPMC;
-
-	if (parent) {
-		pcie_capability_read_word(parent, PCI_EXP_LNKCTL,
-					  &parent_aspmc);
-		parent_aspmc &= PCI_EXP_LNKCTL_ASPMC;
-	}
-
-	/* Nothing to do if the ASPM states to be disabled already are */
-	if (!(pdev_aspmc & aspm_dis_mask) &&
-	    (!parent || !(parent_aspmc & aspm_dis_mask)))
-		return;
-
-	dev_info(&pdev->dev, "Disabling ASPM %s %s\n",
-		 (aspm_dis_mask & pdev_aspmc & PCI_EXP_LNKCTL_ASPM_L0S) ?
-		 "L0s" : "",
-		 (aspm_dis_mask & pdev_aspmc & PCI_EXP_LNKCTL_ASPM_L1) ?
-		 "L1" : "");
-
-#ifdef CONFIG_PCIEASPM
-	if (locked)
-		pci_disable_link_state_locked(pdev, state);
-	else
-		pci_disable_link_state(pdev, state);
-
-	/* Double-check ASPM control.  If not disabled by the above, the
-	 * BIOS is preventing that from happening (or CONFIG_PCIEASPM is
-	 * not enabled); override by writing PCI config space directly.
-	 */
-	pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &pdev_aspmc);
-	pdev_aspmc &= PCI_EXP_LNKCTL_ASPMC;
-
-	if (!(aspm_dis_mask & pdev_aspmc))
-		return;
-#endif
-
-	/* Both device and parent should have the same ASPM setting.
-	 * Disable ASPM in downstream component first and then upstream.
-	 */
-	pcie_capability_clear_word(pdev, PCI_EXP_LNKCTL, aspm_dis_mask);
-
-	if (parent)
-		pcie_capability_clear_word(parent, PCI_EXP_LNKCTL,
-					   aspm_dis_mask);
-}
-
 /**
  * e1000e_disable_aspm - Disable ASPM states.
  * @pdev: pointer to PCI device struct
@@ -6846,7 +6773,7 @@ static void __e1000e_disable_aspm(struct pci_dev *pdev, u16 state, int locked)
  **/
 static void e1000e_disable_aspm(struct pci_dev *pdev, u16 state)
 {
-	__e1000e_disable_aspm(pdev, state, 0);
+	pci_disable_link_state(pdev, state);
 }
 
 /**
@@ -6859,7 +6786,7 @@ static void e1000e_disable_aspm(struct pci_dev *pdev, u16 state)
  **/
 static void e1000e_disable_aspm_locked(struct pci_dev *pdev, u16 state)
 {
-	__e1000e_disable_aspm(pdev, state, 1);
+	pci_disable_link_state_locked(pdev, state);
 }
 
 static int e1000e_pm_thaw(struct device *dev)
-- 
2.30.2