[PATCH] microblaze: Do not place u-boot to reserved memory location

[Michal Simek]

Microblaze can also have reserved space in DT which u-boot has to avoid to
placing self to that location. The same change was done in Zynqmp by commit
ce39ee28ec31 ("zynqmp: Do not place u-boot to reserved memory location").

This feature was tested with this memory description on kc705:

	memory {
		device_type = "memory";
		reg = <0x80000000 0x40000000>;
	};

	reserved-memory {
		#address-cells = <1>;
		#size-cells = <1>;
		ranges;

		alloc at b00000000 {
			reg = <0xb0000000 0x10000000>;
			no-map;
		};

		alloc at a8000000 {
			reg = <0xa8000000 0x00010000>;
			no-map;
		};
	};

And in U-Boot log you can check u-boot relocation address and reserved
locations.
U-Boot 2022.01-03974-gb1b4c2dea9b9 (Feb 25 2022 - 11:59:48 +0100)

Model: Xilinx MicroBlaze
DRAM:  1 GiB
Flash: 128 MiB
Loading Environment from nowhere... OK
In:    serial
Out:   serial
Err:   serial
Model: Xilinx MicroBlaze
Net:   AXI EMAC: 40c00000, phyaddr 7, interface gmii
eth0: ethernet at 40c00000
U-BOOT for microblaze-generic

U-Boot-mONStR> bdi
...
DRAM bank   = 0x00000000
-> start    = 0x80000000
-> size     = 0x40000000
...
relocaddr   = 0xaff69000
...
lmb_dump_all:
 memory.cnt  = 0x1
 memory[0]	[0x80000000-0xbfffffff], 0x40000000 bytes flags: 0
 reserved.cnt  = 0x3
 reserved[0]	[0xa8000000-0xa800ffff], 0x00010000 bytes flags: 4
 reserved[1]	[0xafe87bb0-0xafffffff], 0x00178450 bytes flags: 0
 reserved[2]	[0xb0000000-0xbfffffff], 0x10000000 bytes flags: 4

Signed-off-by: Michal Simek <michal.simek at xilinx.com>
---

 arch/microblaze/include/asm/system.h          |  2 ++
 .../microblaze-generic/microblaze-generic.c   | 21 +++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/arch/microblaze/include/asm/system.h b/arch/microblaze/include/asm/system.h
index 3107748d3bdb..050a8b407636 100644
--- a/arch/microblaze/include/asm/system.h
+++ b/arch/microblaze/include/asm/system.h
@@ -23,6 +23,8 @@
 #endif
 #include <asm/ptrace.h>
 
+#define MMU_SECTION_SIZE	(1 * 1024 * 1024)
+
 #define prepare_to_switch()	do { } while (0)
 
 /*
diff --git a/board/xilinx/microblaze-generic/microblaze-generic.c b/board/xilinx/microblaze-generic/microblaze-generic.c
index a427ac94a170..f58ecd1590c9 100644
--- a/board/xilinx/microblaze-generic/microblaze-generic.c
+++ b/board/xilinx/microblaze-generic/microblaze-generic.c
@@ -14,6 +14,8 @@
 #include <config.h>
 #include <env.h>
 #include <init.h>
+#include <image.h>
+#include <lmb.h>
 #include <log.h>
 #include <asm/global_data.h>
 #include <dm/lists.h>
@@ -36,6 +38,25 @@ int dram_init(void)
 	return 0;
 };
 
+ulong board_get_usable_ram_top(ulong total_size)
+{
+	phys_size_t size;
+	phys_addr_t reg;
+	struct lmb lmb;
+
+	/* found enough not-reserved memory to relocated U-Boot */
+	lmb_init(&lmb);
+	lmb_add(&lmb, gd->ram_base, gd->ram_size);
+	boot_fdt_add_mem_rsv_regions(&lmb, (void *)gd->fdt_blob);
+	size = ALIGN(CONFIG_SYS_MALLOC_LEN + total_size, MMU_SECTION_SIZE);
+	reg = lmb_alloc(&lmb, size, MMU_SECTION_SIZE);
+
+	if (!reg)
+		reg = gd->ram_top - size;
+
+	return reg + size;
+}
+
 int board_late_init(void)
 {
 	ulong max_size;
-- 
2.35.1