Patch "PCI/ASPM: Factor out pcie_wait_for_retrain()" has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    PCI/ASPM: Factor out pcie_wait_for_retrain()

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pci-aspm-factor-out-pcie_wait_for_retrain.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit a03e2f07f1ad1ad75001fb6610db774fa09566ae
Author: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Date:   Tue Jun 20 14:49:33 2023 -0500

    PCI/ASPM: Factor out pcie_wait_for_retrain()
    
    [ Upstream commit 9c7f136433d26592cb4d9cd00b4e15c33d9797c6 ]
    
    Factor pcie_wait_for_retrain() out from pcie_retrain_link().  No functional
    change intended.
    
    [bhelgaas: split out from
    https: //lore.kernel.org/r/20230502083923.34562-1-ilpo.jarvinen@xxxxxxxxxxxxxxx]
    Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
    Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
    Stable-dep-of: e7e39756363a ("PCI/ASPM: Avoid link retraining race")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 86bf1356cfa3f..7b1fb6cb16fba 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -203,10 +203,26 @@ static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
 	link->clkpm_disable = blacklist ? 1 : 0;
 }
 
+static int pcie_wait_for_retrain(struct pci_dev *pdev)
+{
+	unsigned long end_jiffies;
+	u16 reg16;
+
+	/* Wait for Link Training to be cleared by hardware */
+	end_jiffies = jiffies + LINK_RETRAIN_TIMEOUT;
+	do {
+		pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &reg16);
+		if (!(reg16 & PCI_EXP_LNKSTA_LT))
+			return 0;
+		msleep(1);
+	} while (time_before(jiffies, end_jiffies));
+
+	return -ETIMEDOUT;
+}
+
 static int pcie_retrain_link(struct pcie_link_state *link)
 {
 	struct pci_dev *parent = link->pdev;
-	unsigned long end_jiffies;
 	u16 reg16;
 
 	pcie_capability_read_word(parent, PCI_EXP_LNKCTL, &reg16);
@@ -222,17 +238,7 @@ static int pcie_retrain_link(struct pcie_link_state *link)
 		pcie_capability_write_word(parent, PCI_EXP_LNKCTL, reg16);
 	}
 
-	/* Wait for link training end. Break out after waiting for timeout */
-	end_jiffies = jiffies + LINK_RETRAIN_TIMEOUT;
-	do {
-		pcie_capability_read_word(parent, PCI_EXP_LNKSTA, &reg16);
-		if (!(reg16 & PCI_EXP_LNKSTA_LT))
-			break;
-		msleep(1);
-	} while (time_before(jiffies, end_jiffies));
-	if (reg16 & PCI_EXP_LNKSTA_LT)
-		return -ETIMEDOUT;
-	return 0;
+	return pcie_wait_for_retrain(parent);
 }
 
 /*