Thread (13 messages) 13 messages, 5 authors, 2023-02-02

Re: [PATCH v7 2/5] PCI: j721e: Add per platform maximum lane settings

From: Roger Quadros <rogerq@kernel.org>
Date: 2022-11-25 12:27:56
Also in: linux-arm-kernel, linux-omap, linux-pci, lkml

Hi Matt,

On 24/11/2022 10:12, Matt Ranostay wrote:
quoted hunk ↗ jump to hunk
Various platforms have different maximum amount of lanes that can be
selected. Add max_lanes to struct j721e_pcie to allow for detection of this
which is needed to calculate the needed bitmask size for the possible lane
count.

Signed-off-by: Matt Ranostay <redacted>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
---
 drivers/pci/controller/cadence/pci-j721e.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c
index cc83a8925ce0..8990f58d64d5 100644
--- a/drivers/pci/controller/cadence/pci-j721e.c
+++ b/drivers/pci/controller/cadence/pci-j721e.c
@@ -47,8 +47,6 @@ enum link_status {
 
 #define GENERATION_SEL_MASK		GENMASK(1, 0)
 
-#define MAX_LANES			2
-
 struct j721e_pcie {
 	struct cdns_pcie	*cdns_pcie;
 	struct clk		*refclk;
@@ -71,6 +69,7 @@ struct j721e_pcie_data {
 	unsigned int		quirk_disable_flr:1;
 	u32			linkdown_irq_regfield;
 	unsigned int		byte_access_allowed:1;
+	unsigned int		max_lanes;
 };
 
 static inline u32 j721e_pcie_user_readl(struct j721e_pcie *pcie, u32 offset)
@@ -290,11 +289,13 @@ static const struct j721e_pcie_data j721e_pcie_rc_data = {
 	.quirk_retrain_flag = true,
 	.byte_access_allowed = false,
 	.linkdown_irq_regfield = LINK_DOWN,
+	.max_lanes = 2,
 };
 
 static const struct j721e_pcie_data j721e_pcie_ep_data = {
 	.mode = PCI_MODE_EP,
 	.linkdown_irq_regfield = LINK_DOWN,
+	.max_lanes = 2,
 };
 
 static const struct j721e_pcie_data j7200_pcie_rc_data = {
@@ -302,23 +303,27 @@ static const struct j721e_pcie_data j7200_pcie_rc_data = {
 	.quirk_detect_quiet_flag = true,
 	.linkdown_irq_regfield = J7200_LINK_DOWN,
 	.byte_access_allowed = true,
+	.max_lanes = 2,
 };
 
 static const struct j721e_pcie_data j7200_pcie_ep_data = {
 	.mode = PCI_MODE_EP,
 	.quirk_detect_quiet_flag = true,
 	.quirk_disable_flr = true,
+	.max_lanes = 2,
 };
 
 static const struct j721e_pcie_data am64_pcie_rc_data = {
 	.mode = PCI_MODE_RC,
 	.linkdown_irq_regfield = J7200_LINK_DOWN,
 	.byte_access_allowed = true,
+	.max_lanes = 1,
 };
 
 static const struct j721e_pcie_data am64_pcie_ep_data = {
 	.mode = PCI_MODE_EP,
 	.linkdown_irq_regfield = J7200_LINK_DOWN,
+	.max_lanes = 1,
 };
 
 static const struct of_device_id of_j721e_pcie_match[] = {
@@ -432,7 +437,7 @@ static int j721e_pcie_probe(struct platform_device *pdev)
 	pcie->user_cfg_base = base;
 
 	ret = of_property_read_u32(node, "num-lanes", &num_lanes);
-	if (ret || num_lanes > MAX_LANES)
+	if (ret || num_lanes > data->max_lanes)
 		num_lanes = 1;
num_lanes = data->max_lanes; ?

Should we also print an error message saying that invalid num-lanes
was supplied in device tree?
Is it better to error out of probe?
 	pcie->num_lanes = num_lanes;
 
cheers,
-roger
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