p2371-2180: 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>

1 files changed, 47 insertions, 0 deletions

diff --git a/board/nvidia/p2371-2180/p2371-2180.c b/board/nvidia/p2371-2180/p2371-2180.c
index a444d692d7..4985302d6b 100644
--- a/board/nvidia/p2371-2180/p2371-2180.c
+++ b/board/nvidia/p2371-2180/p2371-2180.c
@@ -6,6 +6,7 @@
 
 #include <common.h>
 #include <environment.h>
+#include <fdtdec.h>
 #include <i2c.h>
 #include <linux/libfdt.h>
 #include <asm/arch/gpio.h>
@@ -138,9 +139,55 @@ static void ft_mac_address_setup(void *fdt)
 	}
 }
 
+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@50000000/dc@54200000",
+		"/host1x@50000000/dc@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;
+		}
+	}
+}
+
 int ft_board_setup(void *fdt, bd_t *bd)
 {
 	ft_mac_address_setup(fdt);
+	ft_carveout_setup(fdt);
 
 	return 0;
 }