[PATCH v2 3/7] PCI: aardvark: set host and device to the same MAX payload size

[Thomas Petazzoni]

From: Victor Gu <xigu at marvell.com>

Since the Aardvark does not implement a PCIe root bus, the Linux PCIe
subsystem will not align the MAX payload size between the host and the
device. This patch ensures that the host and device have the same MAX
payload size, fixing a number of problems with various PCIe devices.

This is part of fixing bug
https://bugzilla.kernel.org/show_bug.cgi?id=196339, this commit was
reported as the user to be important to get a Intel 7260 mini-PCIe
WiFi card working.

Fixes: Fixes: 8c39d710363c1 ("PCI: aardvark: Add Aardvark PCI host controller driver")
Signed-off-by: Victor Gu <xigu at marvell.com>
Reviewed-by: Evan Wang <xswang at marvell.com>
Reviewed-by: Nadav Haklai <nadavh at marvell.com>
[Thomas: tweak commit log.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
---
 drivers/pci/host/pci-aardvark.c | 60 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 59 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/host/pci-aardvark.c b/drivers/pci/host/pci-aardvark.c
index af7a9c4a61a4..c8a97bad6c4c 100644
--- a/drivers/pci/host/pci-aardvark.c
+++ b/drivers/pci/host/pci-aardvark.c
@@ -30,8 +30,10 @@
 #define PCIE_CORE_DEV_CTRL_STATS_REG				0xc8
 #define     PCIE_CORE_DEV_CTRL_STATS_RELAX_ORDER_DISABLE	(0 << 4)
 #define     PCIE_CORE_DEV_CTRL_STATS_MAX_PAYLOAD_SZ_SHIFT	5
+#define     PCIE_CORE_DEV_CTRL_STATS_MAX_PAYLOAD_SZ		0x2
 #define     PCIE_CORE_DEV_CTRL_STATS_SNOOP_DISABLE		(0 << 11)
 #define     PCIE_CORE_DEV_CTRL_STATS_MAX_RD_REQ_SIZE_SHIFT	12
+#define     PCIE_CORE_MPS_UNIT_BYTE				128
 #define PCIE_CORE_LINK_CTRL_STAT_REG				0xd0
 #define     PCIE_CORE_LINK_L0S_ENTRY				BIT(0)
 #define     PCIE_CORE_LINK_TRAINING				BIT(5)
@@ -297,7 +299,8 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie)
 
 	/* Set PCIe Device Control and Status 1 PF0 register */
 	reg = PCIE_CORE_DEV_CTRL_STATS_RELAX_ORDER_DISABLE |
-		(7 << PCIE_CORE_DEV_CTRL_STATS_MAX_PAYLOAD_SZ_SHIFT) |
+		(PCIE_CORE_DEV_CTRL_STATS_MAX_PAYLOAD_SZ <<
+		 PCIE_CORE_DEV_CTRL_STATS_MAX_PAYLOAD_SZ_SHIFT) |
 		PCIE_CORE_DEV_CTRL_STATS_SNOOP_DISABLE |
 		PCIE_CORE_DEV_CTRL_STATS_MAX_RD_REQ_SIZE_SHIFT;
 	advk_writel(pcie, reg, PCIE_CORE_DEV_CTRL_STATS_REG);
@@ -879,6 +882,58 @@ static int advk_pcie_parse_request_of_pci_ranges(struct advk_pcie *pcie)
 	return err;
 }
 
+static int advk_pcie_find_smpss(struct pci_dev *dev, void *data)
+{
+	u8 *smpss = data;
+
+	if (!dev)
+		return 0;
+
+	if (!pci_is_pcie(dev))
+		return 0;
+
+	if (*smpss > dev->pcie_mpss)
+		*smpss = dev->pcie_mpss;
+
+	return 0;
+}
+
+static int advk_pcie_bus_configure_mps(struct pci_dev *dev, void *data)
+{
+	int mps;
+
+	if (!dev)
+		return 0;
+
+	if (!pci_is_pcie(dev))
+		return 0;
+
+	mps = PCIE_CORE_MPS_UNIT_BYTE << *(u8 *)data;
+	pcie_set_mps(dev, mps);
+
+	return 0;
+}
+
+static void advk_pcie_configure_mps(struct pci_bus *bus, struct advk_pcie *pcie)
+{
+	u8 smpss = PCIE_CORE_DEV_CTRL_STATS_MAX_PAYLOAD_SZ;
+	u32 reg;
+
+	/* Find the minimal supported MAX payload size */
+	advk_pcie_find_smpss(bus->self, &smpss);
+	pci_walk_bus(bus, advk_pcie_find_smpss, &smpss);
+
+	/* Configure RC MAX payload size */
+	reg = advk_readl(pcie, PCIE_CORE_DEV_CTRL_STATS_REG);
+	reg &= ~PCI_EXP_DEVCTL_PAYLOAD;
+	reg |= smpss << PCIE_CORE_DEV_CTRL_STATS_MAX_PAYLOAD_SZ_SHIFT;
+	advk_writel(pcie, reg, PCIE_CORE_DEV_CTRL_STATS_REG);
+
+	/* Configure device MAX payload size */
+	advk_pcie_bus_configure_mps(bus->self, &smpss);
+	pci_walk_bus(bus, advk_pcie_bus_configure_mps, &smpss);
+}
+
 static int advk_pcie_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -950,6 +1005,9 @@ static int advk_pcie_probe(struct platform_device *pdev)
 	list_for_each_entry(child, &bus->children, node)
 		pcie_bus_configure_settings(child);
 
+	/* Configure the MAX pay load size */
+	advk_pcie_configure_mps(bus, pcie);
+
 	pci_bus_add_devices(bus);
 	return 0;
 }
-- 
2.13.5