PCI: brcmstb: Set new flags to avoid QOS "holes" on BCM2712D0

Set some flags present (and recommended) in 2712D0, but missing
(and harmless) in 2712C1. In particular, EN_QOS_UPDATE_TIMING_FIX
must be set to avoid spurious QOS=0 when the queue changes from
empty to non-empty, to make D0 match the existing C1 behaviour.

Not enabling "QOS forwarding", which still seems not to help.

Signed-off-by: Nick Hollinghurst <nick.hollinghurst@raspberrypi.com>

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 3691e69..e0cb694 100644 (file)
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -199,6 +199,9 @@
 #define  VDM_PRIORITY_TO_QOS_MAP_MASK                  0xf
 
 #define PCIE_MISC_AXI_INTF_CTRL 0x416C
+#define  AXI_EN_RCLK_QOS_ARRAY_FIX                     BIT(13)
+#define  AXI_EN_QOS_UPDATE_TIMING_FIX                  BIT(12)
+#define  AXI_DIS_QOS_GATING_IN_MASTER                  BIT(11)
 #define  AXI_REQFIFO_EN_QOS_PROPAGATION                        BIT(7)
 #define  AXI_BRIDGE_LOW_LATENCY_MODE                   BIT(6)
 #define  AXI_MASTER_MAX_OUTSTANDING_REQUESTS_MASK      0x3f
@@ -558,9 +561,11 @@ static void brcm_pcie_set_tc_qos(struct brcm_pcie *pcie)
        if (pcie->type != BCM2712)
                return;
 
-       /* XXX: BCM2712C0 is broken, disable the forwarding search */
+       /* Disable broken QOS forwarding search. Set chicken bits for 2712D0 */
        reg = readl(pcie->base + PCIE_MISC_AXI_INTF_CTRL);
        reg &= ~AXI_REQFIFO_EN_QOS_PROPAGATION;
+       reg |= AXI_EN_RCLK_QOS_ARRAY_FIX | AXI_EN_QOS_UPDATE_TIMING_FIX |
+               AXI_DIS_QOS_GATING_IN_MASTER;
        writel(reg, pcie->base + PCIE_MISC_AXI_INTF_CTRL);
 
        /* Disable VDM reception by default - QoS map defaults to 0 */