linux-kernel - [PATCH 03/13] PCI: dwc: Refactor dra7xx to use dw_pcie_clear_and_set

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Message-Id: <20250611163113.860528-1-18255117159@163.com>
Date: Thu, 12 Jun 2025 00:31:13 +0800
From: Hans Zhang <18255117159@....com>
To: lpieralisi@...nel.org,
	bhelgaas@...gle.com,
	mani@...nel.org,
	kwilczynski@...nel.org
Cc: robh@...nel.org,
	jingoohan1@...il.com,
	linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Hans Zhang <18255117159@....com>
Subject: [PATCH 03/13] PCI: dwc: Refactor dra7xx to use dw_pcie_clear_and_set_dword()

The dra7xx PCIe driver implements suspend/resume handling through
direct register manipulation. The current approach uses explicit
read-modify-write sequences to control the MEMORY enable bit in the
PCI_COMMAND register, declaring local variables for temporary storage.

Replace manual bit manipulation with dw_pcie_clear_and_set_dword()
during suspend and resume operations. This eliminates redundant variable
declarations and simplifies the power management flow by handling bit
operations within a single function call.

Using the centralized helper improves code readability and aligns the
driver with standard DesignWare register access patterns. The change also
reduces the risk of bit manipulation errors in future modifications to the
power management logic.

Signed-off-by: Hans Zhang <18255117159@....com>
---
 drivers/pci/controller/dwc/pci-dra7xx.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-dra7xx.c b/drivers/pci/controller/dwc/pci-dra7xx.c
index f97f5266d196..9cbba1b28882 100644
--- a/drivers/pci/controller/dwc/pci-dra7xx.c
+++ b/drivers/pci/controller/dwc/pci-dra7xx.c
@@ -867,15 +867,12 @@ static int dra7xx_pcie_suspend(struct device *dev)
 {
 	struct dra7xx_pcie *dra7xx = dev_get_drvdata(dev);
 	struct dw_pcie *pci = dra7xx->pci;
-	u32 val;

 	if (dra7xx->mode != DW_PCIE_RC_TYPE)
 		return 0;

 	/* clear MSE */
-	val = dw_pcie_readl_dbi(pci, PCI_COMMAND);
-	val &= ~PCI_COMMAND_MEMORY;
-	dw_pcie_writel_dbi(pci, PCI_COMMAND, val);
+	dw_pcie_clear_and_set_dword(pci, PCI_COMMAND, PCI_COMMAND_MEMORY, 0);

 	return 0;
 }
@@ -884,15 +881,12 @@ static int dra7xx_pcie_resume(struct device *dev)
 {
 	struct dra7xx_pcie *dra7xx = dev_get_drvdata(dev);
 	struct dw_pcie *pci = dra7xx->pci;
-	u32 val;

 	if (dra7xx->mode != DW_PCIE_RC_TYPE)
 		return 0;

 	/* set MSE */
-	val = dw_pcie_readl_dbi(pci, PCI_COMMAND);
-	val |= PCI_COMMAND_MEMORY;
-	dw_pcie_writel_dbi(pci, PCI_COMMAND, val);
+	dw_pcie_clear_and_set_dword(pci, PCI_COMMAND, 0, PCI_COMMAND_MEMORY);

 	return 0;
 }
-- 
2.25.1