[U-Boot] [PATCH 6/6] p2371-2180: Add support for framebuffer carveouts

[Thierry Reding]

From: Thierry Reding <treding at nvidia.com>

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.

Signed-off-by: Thierry Reding <treding at nvidia.com>
---
 board/nvidia/p2371-2180/p2371-2180.c | 50 ++++++++++++++++++++++++++++
 configs/p2371-2180_defconfig         |  1 +
 2 files changed, 51 insertions(+)

diff --git a/board/nvidia/p2371-2180/p2371-2180.c b/board/nvidia/p2371-2180/p2371-2180.c
index 212037da5ac0..d81deb0cd320 100644
--- a/board/nvidia/p2371-2180/p2371-2180.c
+++ b/board/nvidia/p2371-2180/p2371-2180.c
@@ -6,8 +6,11 @@
 
 #include <common.h>
 #include <i2c.h>
+#include <linux/libfdt.h>
+#include <fdtdec.h>
 #include <asm/arch/gpio.h>
 #include <asm/arch/pinmux.h>
+#include <asm/arch-tegra/cboot.h>
 #include "../p2571/max77620_init.h"
 #include "pinmux-config-p2371-2180.h"
 
@@ -94,3 +97,50 @@ int tegra_pcie_board_init(void)
 	return 0;
 }
 #endif /* PCI */
+
+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;
+}
+
+int ft_board_setup(void *fdt, bd_t *bd)
+{
+	const void *cboot_fdt = (const void *)cboot_boot_x0;
+	static const char * const nodes[] = {
+		"/host1x at 50000000/dc at 54200000",
+		"/host1x at 50000000/dc at 54240000",
+	};
+	unsigned int i;
+	int err;
+
+	for (i = 0; i < ARRAY_SIZE(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;
+		}
+	}
+
+	return 0;
+}
diff --git a/configs/p2371-2180_defconfig b/configs/p2371-2180_defconfig
index b662ef143141..b66459e379ac 100644
--- a/configs/p2371-2180_defconfig
+++ b/configs/p2371-2180_defconfig
@@ -5,6 +5,7 @@ CONFIG_TEGRA210=y
 CONFIG_TARGET_P2371_2180=y
 CONFIG_NR_DRAM_BANKS=2
 CONFIG_OF_SYSTEM_SETUP=y
+CONFIG_OF_BOARD_SETUP=y
 CONFIG_CONSOLE_MUX=y
 CONFIG_SYS_STDIO_DEREGISTER=y
 CONFIG_SYS_PROMPT="Tegra210 (P2371-2180) # "
-- 
2.20.1