From:   =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org>
To:     Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Rob Herring <robh@kernel.org>,
        =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= <kw@linux.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        =?UTF-8?q?Marek=20Beh=C3=BAn?= <kabel@kernel.org>
Cc:     linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2 10/11] PCI: mvebu: Update comment for PCI_EXP_LNKCTL register on emulated bridge
Date:   Tue,  4 Jan 2022 16:35:28 +0100
Message-Id: <20220104153529.31647-11-pali@kernel.org>
In-Reply-To: <20220104153529.31647-1-pali@kernel.org>
References: <20211221141455.30011-1-pali@kernel.org>
 <20220104153529.31647-1-pali@kernel.org>
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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;
 
-- 
2.20.1