linux-kernel - [PATCH v3 1/3] PCI: qcom: Make use of PCIE_SPEED2MBS

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Message-Id: <20230927154603.172049-1-manivannan.sadhasivam@linaro.org>
Date:   Wed, 27 Sep 2023 17:46:01 +0200
From:   Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To:     lpieralisi@...nel.org, kw@...ux.com
Cc:     andersson@...nel.org, konrad.dybcio@...aro.org,
        bhelgaas@...gle.com, linux-arm-msm@...r.kernel.org,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        abel.vesa@...aro.org,
        Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Subject: [PATCH v3 1/3] PCI: qcom: Make use of PCIE_SPEED2MBS_ENC() macro for encoding link speed

Instead of hardcoding the link speed in MBps, let's make use of the
existing PCIE_SPEED2MBS_ENC() macro that does the encoding of the
link speed for us. Also, let's Wrap it with QCOM_PCIE_LINK_SPEED_TO_BW()
macro to do the conversion to ICC speed.

This eliminates the need for a switch case in qcom_pcie_icc_update() and
also works for future Gen speeds without any code modifications.

Suggested-by: Bjorn Helgaas <bhelgaas@...gle.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
---

Changes in v3:

- Used Mbps_to_icc() macro and changed the commit message a bit

Changes in v2:

- Switched to QCOM_PCIE_LINK_SPEED_TO_BW() macro as per Bjorn's suggestion
  https://lore.kernel.org/linux-pci/20230924160713.217086-1-manivannan.sadhasivam@linaro.org/

 drivers/pci/controller/dwc/pcie-qcom.c | 24 ++++++------------------
 1 file changed, 6 insertions(+), 18 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index e2f29404c84e..367acb419a2b 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -148,6 +148,9 @@
 
 #define QCOM_PCIE_CRC8_POLYNOMIAL		(BIT(2) | BIT(1) | BIT(0))
 
+#define QCOM_PCIE_LINK_SPEED_TO_BW(speed) \
+		Mbps_to_icc(PCIE_SPEED2MBS_ENC(pcie_link_speed[speed]))
+
 #define QCOM_PCIE_1_0_0_MAX_CLOCKS		4
 struct qcom_pcie_resources_1_0_0 {
 	struct clk_bulk_data clks[QCOM_PCIE_1_0_0_MAX_CLOCKS];
@@ -1347,7 +1350,7 @@ static int qcom_pcie_icc_init(struct qcom_pcie *pcie)
 	 * Set an initial peak bandwidth corresponding to single-lane Gen 1
 	 * for the pcie-mem path.
 	 */
-	ret = icc_set_bw(pcie->icc_mem, 0, MBps_to_icc(250));
+	ret = icc_set_bw(pcie->icc_mem, 0, QCOM_PCIE_LINK_SPEED_TO_BW(1));
 	if (ret) {
 		dev_err(pci->dev, "failed to set interconnect bandwidth: %d\n",
 			ret);
@@ -1360,7 +1363,7 @@ static int qcom_pcie_icc_init(struct qcom_pcie *pcie)
 static void qcom_pcie_icc_update(struct qcom_pcie *pcie)
 {
 	struct dw_pcie *pci = pcie->pci;
-	u32 offset, status, bw;
+	u32 offset, status;
 	int speed, width;
 	int ret;
 
@@ -1377,22 +1380,7 @@ static void qcom_pcie_icc_update(struct qcom_pcie *pcie)
 	speed = FIELD_GET(PCI_EXP_LNKSTA_CLS, status);
 	width = FIELD_GET(PCI_EXP_LNKSTA_NLW, status);
 
-	switch (speed) {
-	case 1:
-		bw = MBps_to_icc(250);
-		break;
-	case 2:
-		bw = MBps_to_icc(500);
-		break;
-	default:
-		WARN_ON_ONCE(1);
-		fallthrough;
-	case 3:
-		bw = MBps_to_icc(985);
-		break;
-	}
-
-	ret = icc_set_bw(pcie->icc_mem, 0, width * bw);
+	ret = icc_set_bw(pcie->icc_mem, 0, width * QCOM_PCIE_LINK_SPEED_TO_BW(speed));
 	if (ret) {
 		dev_err(pci->dev, "failed to set interconnect bandwidth: %d\n",
 			ret);
-- 
2.25.1