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drivers: pcie-brcmstb: add best-effort workaround for QoS bug on bcm2712 #6183

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Merged
pelwell merged 1 commit into from
May 22, 2024
Merged

drivers: pcie-brcmstb: add best-effort workaround for QoS bug on bcm2712 #6183

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12 changes: 12 additions & 0 deletions drivers/pci/controller/pcie-brcmstb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -568,6 +568,18 @@ static void brcm_pcie_set_tc_qos(struct brcm_pcie *pcie)
AXI_DIS_QOS_GATING_IN_MASTER;
writel(reg, pcie->base + PCIE_MISC_AXI_INTF_CTRL);

/*
* If the QOS_UPDATE_TIMING_FIX bit is Reserved-0, then this is a
* 2712C1 chip, or a single-lane RC. Use the best-effort alternative
* which is to partially throttle AXI requests in-flight to the SDC.
*/
reg = readl(pcie->base + PCIE_MISC_AXI_INTF_CTRL);
if (!(reg & AXI_EN_QOS_UPDATE_TIMING_FIX)) {
reg &= ~AXI_MASTER_MAX_OUTSTANDING_REQUESTS_MASK;
reg |= 15;
writel(reg, pcie->base + PCIE_MISC_AXI_INTF_CTRL);
}

/* Disable VDM reception by default - QoS map defaults to 0 */
reg = readl(pcie->base + PCIE_MISC_CTRL_1);
reg &= ~PCIE_MISC_CTRL_1_EN_VDM_QOS_CONTROL_MASK;
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