uboot-tools/Raspberry-Pi-4-PCIe-handover.patch

From 5e2954fae6081daf8d65ba28dd0edef3527f5d31 Mon Sep 17 00:00:00 2001
From: Peter Robinson <pbrobinson@gmail.com>
Date: Thu, 14 Jan 2021 17:07:18 +0000
Subject: [PATCH 1/2] usb: xhci-pci: Add DM_FLAG_OS_PREPARE flag

The PCIe bus the controller is connected to might need to be removed
prior the handover. Make sure xhci-pci is also removed so as to avoid
unexpected timeouts or hangs.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
---
 drivers/usb/host/xhci-pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 9fb6d2f763..19f8fb4458 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -61,7 +61,7 @@ U_BOOT_DRIVER(xhci_pci) = {
 	.ops	= &xhci_usb_ops,
 	.platdata_auto_alloc_size = sizeof(struct usb_platdata),
 	.priv_auto_alloc_size = sizeof(struct xhci_ctrl),
-	.flags	= DM_FLAG_ALLOC_PRIV_DMA,
+	.flags	= DM_FLAG_OS_PREPARE | DM_FLAG_ALLOC_PRIV_DMA,
 };
 
 static struct pci_device_id xhci_pci_supported[] = {
-- 
2.29.2

From 162e817b0196c418bcf5d02cedf2d823f3497321 Mon Sep 17 00:00:00 2001
From: Peter Robinson <pbrobinson@gmail.com>
Date: Thu, 14 Jan 2021 17:09:47 +0000
Subject: [PATCH 2/2] pci: brcmstb: Cleanup controller state before handover

Make sure we handover the PCIe controller in a clean state. Some of the
devices hanging from the PCIe bus might need to be properly reset
through #PERST in order for Linux to be able to initialize them.

This is specially important in order to properly initialize Raspberry Pi
4 B and 400's USB chip.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
---
 drivers/pci/pcie_brcmstb.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/pci/pcie_brcmstb.c b/drivers/pci/pcie_brcmstb.c
index f6e8ad0d0a..de824a4d9b 100644
--- a/drivers/pci/pcie_brcmstb.c
+++ b/drivers/pci/pcie_brcmstb.c
@@ -577,6 +577,24 @@ static int brcm_pcie_probe(struct udevice *dev)
 	return 0;
 }
 
+static int brcm_pcie_remove(struct udevice *dev)
+{
+	struct brcm_pcie *pcie = dev_get_priv(dev);
+	void __iomem *base = pcie->base;
+
+	/* Assert fundamental reset */
+	setbits_le32(base + PCIE_RGR1_SW_INIT_1, RGR1_SW_INIT_1_PERST_MASK);
+
+	/* Turn off SerDes */
+	setbits_le32(base + PCIE_MISC_HARD_PCIE_HARD_DEBUG,
+		     PCIE_HARD_DEBUG_SERDES_IDDQ_MASK);
+
+	/* Shutdown bridge */
+	setbits_le32(base + PCIE_RGR1_SW_INIT_1, RGR1_SW_INIT_1_INIT_MASK);
+
+	return 0;
+}
+
 static int brcm_pcie_ofdata_to_platdata(struct udevice *dev)
 {
 	struct brcm_pcie *pcie = dev_get_priv(dev);
@@ -616,6 +634,7 @@ U_BOOT_DRIVER(pcie_brcm_base) = {
 	.ops			= &brcm_pcie_ops,
 	.of_match		= brcm_pcie_ids,
 	.probe			= brcm_pcie_probe,
+	.remove			= brcm_pcie_remove,
 	.ofdata_to_platdata	= brcm_pcie_ofdata_to_platdata,
 	.priv_auto_alloc_size	= sizeof(struct brcm_pcie),
 };
-- 
2.29.2