From c79aa81dbc8a753ac8b00adbfb8c355933b89caa Mon Sep 17 00:00:00 2001
From: Thierry Reding <treding@nvidia.com>
Date: Mon, 15 Apr 2019 11:32:36 +0200
Subject: [PATCH] p2771-0000: Add support for framebuffer carveouts

If early firmware initialized the display hardware and the display
controllers are scanning out a framebuffer (e.g. a splash screen), make
sure to pass information about the memory location of that framebuffer
to the kernel before booting to avoid the kernel from using that memory
for the buddy allocator.

This same mechanism can also be used in the kernel to set up early SMMU
mappings and avoid SMMU faults caused by the display controller reading
from memory for which it has no mapping.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
---
 board/nvidia/p2771-0000/p2771-0000.c | 66 ++++++++++++++++++++++++++--
 1 file changed, 62 insertions(+), 4 deletions(-)

diff --git a/board/nvidia/p2771-0000/p2771-0000.c b/board/nvidia/p2771-0000/p2771-0000.c
index fe22067f65..d294c7ae01 100644
--- a/board/nvidia/p2771-0000/p2771-0000.c
+++ b/board/nvidia/p2771-0000/p2771-0000.c
@@ -5,6 +5,7 @@
 
 #include <common.h>
 #include <environment.h>
+#include <fdtdec.h>
 #include <i2c.h>
 #include <linux/libfdt.h>
 #include <asm/arch-tegra/cboot.h>
@@ -56,7 +57,7 @@ int tegra_pcie_board_init(void)
 }
 #endif
 
-int ft_board_setup(void *fdt, bd_t *bd)
+static void ft_mac_address_setup(void *fdt)
 {
 	const void *cboot_fdt = (const void *)cboot_boot_x0;
 	uint8_t mac[ETH_ALEN], local_mac[ETH_ALEN];
@@ -69,13 +70,15 @@ int ft_board_setup(void *fdt, bd_t *bd)
 
 	path = fdt_get_alias(fdt, "ethernet");
 	if (!path)
-		return 0;
+		return;
 
 	debug("ethernet alias found: %s\n", path);
 
 	offset = fdt_path_offset(fdt, path);
-	if (offset < 0)
-		return 0;
+	if (offset < 0) {
+		printf("ethernet alias points to absent node %s\n", path);
+		return;
+	}
 
 	if (is_valid_ethaddr(local_mac)) {
 		err = fdt_setprop(fdt, offset, "local-mac-address", local_mac,
@@ -92,6 +95,61 @@ int ft_board_setup(void *fdt, bd_t *bd)
 				debug("MAC address set: %pM\n", mac);
 		}
 	}
+}
+
+static int ft_copy_carveout(void *dst, const void *src, const char *node)
+{
+	struct fdt_memory fb;
+	int err;
+
+	err = fdtdec_get_carveout(src, node, "memory-region", 0, &fb);
+	if (err < 0) {
+		if (err != -FDT_ERR_NOTFOUND)
+			printf("failed to get carveout for %s: %d\n", node,
+			       err);
+
+		return err;
+	}
+
+	err = fdtdec_set_carveout(dst, node, "memory-region", 0, "framebuffer",
+				  &fb);
+	if (err < 0) {
+		printf("failed to set carveout for %s: %d\n", node, err);
+		return err;
+	}
+
+	return 0;
+}
+
+static void ft_carveout_setup(void *fdt)
+{
+	const void *cboot_fdt = (const void *)cboot_boot_x0;
+	static const char * const nodes[] = {
+		"/host1x@13e00000/display-hub@15200000/display@15200000",
+		"/host1x@13e00000/display-hub@15200000/display@15210000",
+		"/host1x@13e00000/display-hub@15200000/display@15220000",
+	};
+	unsigned int i;
+	int err;
+
+	for (i = 0; i < ARRAY_SIZE(nodes); i++) {
+		printf("copying carveout for %s...\n", nodes[i]);
+
+		err = ft_copy_carveout(fdt, cboot_fdt, nodes[i]);
+		if (err < 0) {
+			if (err != -FDT_ERR_NOTFOUND)
+				printf("failed to copy carveout for %s: %d\n",
+				       nodes[i], err);
+
+			continue;
+		}
+	}
+}
+
+int ft_board_setup(void *fdt, bd_t *bd)
+{
+	ft_mac_address_setup(fdt);
+	ft_carveout_setup(fdt);
 
 	return 0;
 }
-- 
2.30.2