linux-kernel - [PATCH 3.16 020/132] PCI: Factor out pcie_retrain

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Message-ID: <lsq.1568989415.605726088@decadent.org.uk>
Date:   Fri, 20 Sep 2019 15:23:35 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Stefan Mätje" <stefan.maetje@....eu>,
        "Andy Shevchenko" <andriy.shevchenko@...ux.intel.com>,
        "Bjorn Helgaas" <bhelgaas@...gle.com>
Subject: [PATCH 3.16 020/132] PCI: Factor out pcie_retrain_link() function

3.16.74-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Stefan Mätje <stefan.maetje@....eu>

commit 86fa6a344209d9414ea962b1f1ac6ade9dd7563a upstream.

Factor out pcie_retrain_link() to use for Pericom Retrain Link quirk.  No
functional change intended.

Signed-off-by: Stefan Mätje <stefan.maetje@....eu>
Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/pci/pcie/aspm.c | 40 ++++++++++++++++++++++++----------------
 1 file changed, 24 insertions(+), 16 deletions(-)

--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -175,6 +175,29 @@ static void pcie_clkpm_cap_init(struct p
 	link->clkpm_capable = (blacklist) ? 0 : capable;
 }
 
+static bool pcie_retrain_link(struct pcie_link_state *link)
+{
+	struct pci_dev *parent = link->pdev;
+	unsigned long start_jiffies;
+	u16 reg16;
+
+	pcie_capability_read_word(parent, PCI_EXP_LNKCTL, &reg16);
+	reg16 |= PCI_EXP_LNKCTL_RL;
+	pcie_capability_write_word(parent, PCI_EXP_LNKCTL, reg16);
+
+	/* Wait for link training end. Break out after waiting for timeout */
+	start_jiffies = jiffies;
+	for (;;) {
+		pcie_capability_read_word(parent, PCI_EXP_LNKSTA, &reg16);
+		if (!(reg16 & PCI_EXP_LNKSTA_LT))
+			break;
+		if (time_after(jiffies, start_jiffies + LINK_RETRAIN_TIMEOUT))
+			break;
+		msleep(1);
+	}
+	return !(reg16 & PCI_EXP_LNKSTA_LT);
+}
+
 /*
  * pcie_aspm_configure_common_clock: check if the 2 ends of a link
  *   could use common clock. If they are, configure them to use the
@@ -184,7 +207,6 @@ static void pcie_aspm_configure_common_c
 {
 	int same_clock = 1;
 	u16 reg16, parent_reg, child_reg[8];
-	unsigned long start_jiffies;
 	struct pci_dev *child, *parent = link->pdev;
 	struct pci_bus *linkbus = parent->subordinate;
 	/*
@@ -224,21 +246,7 @@ static void pcie_aspm_configure_common_c
 		reg16 &= ~PCI_EXP_LNKCTL_CCC;
 	pcie_capability_write_word(parent, PCI_EXP_LNKCTL, reg16);
 
-	/* Retrain link */
-	reg16 |= PCI_EXP_LNKCTL_RL;
-	pcie_capability_write_word(parent, PCI_EXP_LNKCTL, reg16);
-
-	/* Wait for link training end. Break out after waiting for timeout */
-	start_jiffies = jiffies;
-	for (;;) {
-		pcie_capability_read_word(parent, PCI_EXP_LNKSTA, &reg16);
-		if (!(reg16 & PCI_EXP_LNKSTA_LT))
-			break;
-		if (time_after(jiffies, start_jiffies + LINK_RETRAIN_TIMEOUT))
-			break;
-		msleep(1);
-	}
-	if (!(reg16 & PCI_EXP_LNKSTA_LT))
+	if (pcie_retrain_link(link))
 		return;
 
 	/* Training failed. Restore common clock configurations */