Add bare minimum amount of changes in order to support PCIe RC hardware
IP found on RPi5. The PCIe controller on bcm2712 is based on bcm7712 and
as such it inherits register offsets, perst, bridge_reset ops and inbound
windows count.
Although, the implementation for bcm2712 needs a workaround related to the
control of the bridge_reset where turning off of the root port must not
shutdown the bridge_reset and this must be avoided. To implement this
workaround a quirks field is introduced in pcie_cfg_data struct.

Signed-off-by: Stanimir Varbanov <svarbanov@suse.de>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
---
v3 -> v4:
 - Merged "PCI: brcmstb: Avoid turn off of bridge reset" from v3 here
   in this patch (Bjorn)

 drivers/pci/controller/pcie-brcmstb.c | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index af01a7915c94..d970a76aa9ef 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -234,10 +234,20 @@ struct inbound_win {
 	u64 cpu_addr;
 };
 
+/*
+ * The RESCAL block is tied to PCIe controller #1, regardless of the number of
+ * controllers, and turning off PCIe controller #1 prevents access to the RESCAL
+ * register blocks, therefore no other controller can access this register
+ * space, and depending upon the bus fabric we may get a timeout (UBUS/GISB),
+ * or a hang (AXI).
+ */
+#define CFG_QUIRK_AVOID_BRIDGE_SHUTDOWN		BIT(0)
+
 struct pcie_cfg_data {
 	const int *offsets;
 	const enum pcie_soc_base soc_base;
 	const bool has_phy;
+	const u32 quirks;
 	u8 num_inbound_wins;
 	int (*perst_set)(struct brcm_pcie *pcie, u32 val);
 	int (*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
@@ -1534,8 +1544,9 @@ static int brcm_pcie_turn_off(struct brcm_pcie *pcie)
 	u32p_replace_bits(&tmp, 1, PCIE_MISC_HARD_PCIE_HARD_DEBUG_SERDES_IDDQ_MASK);
 	writel(tmp, base + HARD_DEBUG(pcie));
 
-	/* Shutdown PCIe bridge */
-	ret = pcie->bridge_sw_init_set(pcie, 1);
+	if (!(pcie->cfg->quirks & CFG_QUIRK_AVOID_BRIDGE_SHUTDOWN))
+		/* Shutdown PCIe bridge */
+		ret = pcie->cfg->bridge_sw_init_set(pcie, 1);
 
 	return ret;
 }
@@ -1745,6 +1756,15 @@ static const struct pcie_cfg_data bcm2711_cfg = {
 	.num_inbound_wins = 3,
 };
 
+static const struct pcie_cfg_data bcm2712_cfg = {
+	.offsets	= pcie_offsets_bcm7712,
+	.soc_base	= BCM7712,
+	.perst_set	= brcm_pcie_perst_set_7278,
+	.bridge_sw_init_set = brcm_pcie_bridge_sw_init_set_generic,
+	.quirks		= CFG_QUIRK_AVOID_BRIDGE_SHUTDOWN,
+	.num_inbound_wins = 10,
+};
+
 static const struct pcie_cfg_data bcm4908_cfg = {
 	.offsets	= pcie_offsets,
 	.soc_base	= BCM4908,
@@ -1796,6 +1816,7 @@ static const struct pcie_cfg_data bcm7712_cfg = {
 
 static const struct of_device_id brcm_pcie_match[] = {
 	{ .compatible = "brcm,bcm2711-pcie", .data = &bcm2711_cfg },
+	{ .compatible = "brcm,bcm2712-pcie", .data = &bcm2712_cfg },
 	{ .compatible = "brcm,bcm4908-pcie", .data = &bcm4908_cfg },
 	{ .compatible = "brcm,bcm7211-pcie", .data = &generic_cfg },
 	{ .compatible = "brcm,bcm7216-pcie", .data = &bcm7216_cfg },
-- 
2.43.0