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path: root/pkgs/patches-linux-5.15/0022-PCI-mvebu-Update-comment-for-PCI_EXP_LNKCTL-register.patch
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From b47763b59b70859fdcb98e228ac5d762cca39ab7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org>
Date: Fri, 17 Sep 2021 11:57:20 +0200
Subject: [PATCH 22/90] PCI: mvebu: Update comment for PCI_EXP_LNKCTL register
 on emulated bridge
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Logic and code for clearing PCI_EXP_LNKCTL_CLKREQ_EN bit is correct, but
comment describing it is misleading. PCI_EXP_LNKCTL_CLKREQ_EN bit should be
hardwired to zero but mvebu hw allows to change it.

Signed-off-by: Pali Rohár <pali@kernel.org>
---
 drivers/pci/controller/pci-mvebu.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pci-mvebu.c
index 1aac65977b97..dffa330de174 100644
--- a/drivers/pci/controller/pci-mvebu.c
+++ b/drivers/pci/controller/pci-mvebu.c
@@ -663,10 +663,9 @@ mvebu_pci_bridge_emul_pcie_conf_write(struct pci_bridge_emul *bridge,
 
 	case PCI_EXP_LNKCTL:
 		/*
-		 * If we don't support CLKREQ, we must ensure that the
-		 * CLKREQ enable bit always reads zero.  Since we haven't
-		 * had this capability, and it's dependent on board wiring,
-		 * disable it for the time being.
+		 * PCIe requires that the Enable Clock Power Management bit
+		 * is hard-wired to zero for downstream ports but HW allows
+		 * to change it.
 		 */
 		new &= ~PCI_EXP_LNKCTL_CLKREQ_EN;
 
-- 
2.34.1