linux-kernel - [PATCH 14/15] PCI: brcmstb: Set bus max burst side by chip type

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Date:   Tue, 19 May 2020 16:34:12 -0400
From:   Jim Quinlan <james.quinlan@...adcom.com>
To:     james.quinlan@...adcom.com,
        Nicolas Saenz Julienne <nsaenzjulienne@...e.de>
Cc:     Jim Quinlan <james.quinlan@...adcom.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        bcm-kernel-feedback-list@...adcom.com (maintainer:BROADCOM BCM7XXX ARM
        ARCHITECTURE),
        linux-rpi-kernel@...ts.infradead.org (moderated list:BROADCOM
        BCM2711/BCM2835 ARM ARCHITECTURE),
        linux-arm-kernel@...ts.infradead.org (moderated list:BROADCOM
        BCM2711/BCM2835 ARM ARCHITECTURE),
        linux-pci@...r.kernel.org (open list:PCI NATIVE HOST BRIDGE AND
        ENDPOINT DRIVERS), linux-kernel@...r.kernel.org (open list)
Subject: [PATCH 14/15] PCI: brcmstb: Set bus max burst side by chip type

From: Jim Quinlan <jquinlan@...adcom.com>

The proper value of the parameter SCB_MAX_BURST_SIZE varies
per chip.  The 2711 family requires 128B whereas other devices
can employ 512.  The assignment is complicated by the fact
that the values for this two-bit field have different meanings;

  Value   Type_Generic    Type_7278

     00       Reserved         128B
     01           128B         256B
     10           256B         512B
     11           512B     Reserved

Signed-off-by: Jim Quinlan <jquinlan@...adcom.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 7bf945efd71b..0dfa1bbd9764 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -53,7 +53,7 @@
 #define  PCIE_MISC_MISC_CTRL_SCB_ACCESS_EN_MASK		0x1000
 #define  PCIE_MISC_MISC_CTRL_CFG_READ_UR_MODE_MASK	0x2000
 #define  PCIE_MISC_MISC_CTRL_MAX_BURST_SIZE_MASK	0x300000
-#define  PCIE_MISC_MISC_CTRL_MAX_BURST_SIZE_128		0x0
+
 #define  PCIE_MISC_MISC_CTRL_SCB0_SIZE_MASK		0xf8000000
 #define  PCIE_MISC_MISC_CTRL_SCB1_SIZE_MASK		0x07c00000
 #define  PCIE_MISC_MISC_CTRL_SCB2_SIZE_MASK		0x0000001f
@@ -276,6 +276,7 @@ struct brcm_pcie {
 	int			num_memc;
 	u64			memc_size[PCIE_BRCM_MAX_MEMC];
 	u32			hw_rev;
+	const struct of_device_id *of_id;
 };
 
 /*
@@ -841,7 +842,7 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 	int num_out_wins = 0;
 	u16 nlw, cls, lnksta;
 	int i, ret, memc;
-	u32 tmp, aspm_support;
+	u32 tmp, burst, aspm_support;
 
 	/* Reset the bridge */
 	brcm_pcie_bridge_sw_init_set(pcie, 1);
@@ -857,10 +858,20 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 	/* Wait for SerDes to be stable */
 	usleep_range(100, 200);
 
+	/*
+	 * SCB_MAX_BURST_SIZE is a two bit field.  For GENERIC chips it
+	 * is encoded as 0=128, 1=256, 2=512, 3=Rsvd, for BCM7278 it
+	 * is encoded as 0=Rsvd, 1=128, 2=256, 3=512.
+	 */
+	if (strcmp(pcie->of_id->compatible, "brcm,bcm2711-pcie") == 0)
+		burst = 0x0; /* 128B */
+	else
+		burst = (pcie->type == BCM7278) ? 0x3 : 0x2; /* 512 bytes */
+
 	/* Set SCB_MAX_BURST_SIZE, CFG_READ_UR_MODE, SCB_ACCESS_EN */
 	u32p_replace_bits(&tmp, 1, PCIE_MISC_MISC_CTRL_SCB_ACCESS_EN_MASK);
 	u32p_replace_bits(&tmp, 1, PCIE_MISC_MISC_CTRL_CFG_READ_UR_MODE_MASK);
-	u32p_replace_bits(&tmp, PCIE_MISC_MISC_CTRL_MAX_BURST_SIZE_128,
+	u32p_replace_bits(&tmp, burst,
 			  PCIE_MISC_MISC_CTRL_MAX_BURST_SIZE_MASK);
 	writel(tmp, base + PCIE_MISC_MISC_CTRL);
 
@@ -1200,6 +1211,7 @@ static int brcm_pcie_probe(struct platform_device *pdev)
 	pcie->reg_offsets = data->offsets;
 	pcie->reg_field_info = data->reg_field_info;
 	pcie->type = data->type;
+	pcie->of_id = of_id;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	pcie->base = devm_ioremap_resource(&pdev->dev, res);
-- 
2.17.1