PCI: qcom-ep: Use PCIE_SPEED2MBS_ENC() macro for encoding link speed

Instead of hardcoding the link speed in MBps, use 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@google.com>
Link: https://lore.kernel.org/linux-pci/20231004164430.39662-2-manivannan.sadhasivam@linaro.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Author: Mani-Sadhasivam

drivers/pci/controller/dwc/pcie-qcom-ep.c

@@ -23,6 +23,7 @@
 #include <linux/reset.h>
 #include <linux/module.h>
 
+#include "../../pci.h"
 #include "pcie-designware.h"
 
 /* PARF registers */
@@ -135,10 +136,8 @@
 #define CORE_RESET_TIME_US_MAX			1005
 #define WAKE_DELAY_US				2000 /* 2 ms */
 
-#define PCIE_GEN1_BW_MBPS			250
-#define PCIE_GEN2_BW_MBPS			500
-#define PCIE_GEN3_BW_MBPS			985
-#define PCIE_GEN4_BW_MBPS			1969
+#define QCOM_PCIE_LINK_SPEED_TO_BW(speed) \
+		Mbps_to_icc(PCIE_SPEED2MBS_ENC(pcie_link_speed[speed]))
 
 #define to_pcie_ep(x)				dev_get_drvdata((x)->dev)
 
@@ -266,7 +265,7 @@ static void qcom_pcie_dw_stop_link(struct dw_pcie *pci)
 static void qcom_pcie_ep_icc_update(struct qcom_pcie_ep *pcie_ep)
 {
 	struct dw_pcie *pci = &pcie_ep->pci;
-	u32 offset, status, bw;
+	u32 offset, status;
 	int speed, width;
 	int ret;
 
@@ -279,25 +278,7 @@ static void qcom_pcie_ep_icc_update(struct qcom_pcie_ep *pcie_ep)
 	speed = FIELD_GET(PCI_EXP_LNKSTA_CLS, status);
 	width = FIELD_GET(PCI_EXP_LNKSTA_NLW, status);
 
-	switch (speed) {
-	case 1:
-		bw = MBps_to_icc(PCIE_GEN1_BW_MBPS);
-		break;
-	case 2:
-		bw = MBps_to_icc(PCIE_GEN2_BW_MBPS);
-		break;
-	case 3:
-		bw = MBps_to_icc(PCIE_GEN3_BW_MBPS);
-		break;
-	default:
-		dev_warn(pci->dev, "using default GEN4 bandwidth\n");
-		fallthrough;
-	case 4:
-		bw = MBps_to_icc(PCIE_GEN4_BW_MBPS);
-		break;
-	}
-
-	ret = icc_set_bw(pcie_ep->icc_mem, 0, width * bw);
+	ret = icc_set_bw(pcie_ep->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);
@@ -335,7 +316,7 @@ static int qcom_pcie_enable_resources(struct qcom_pcie_ep *pcie_ep)
 	 * Set an initial peak bandwidth corresponding to single-lane Gen 1
 	 * for the pcie-mem path.
 	 */
-	ret = icc_set_bw(pcie_ep->icc_mem, 0, MBps_to_icc(PCIE_GEN1_BW_MBPS));
+	ret = icc_set_bw(pcie_ep->icc_mem, 0, QCOM_PCIE_LINK_SPEED_TO_BW(1));
 	if (ret) {
 		dev_err(pci->dev, "failed to set interconnect bandwidth: %d\n",
 			ret);