ARM: rmobile: Generate fitting mem_map on Gen3

Patch "ARM: rmobile: Mark 4-64GiB as DRAM on Gen3" marked the entire
64bit DRAM space as cachable. On CortexA57, this might result in odd
side effects, where the CPU tries to prefetch from those areas and if
there is no DRAM backing them, CPU bus hang can happen.

This patch fixes it by generating the mem_map structure based on the
actual memory layout obtained from the DT, thus not marking areas
without any DRAM behind them as cachable.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Fixes: c1ec34763811d ("ARM: rmobile: Mark 4-64GiB as DRAM on Gen3")
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

1 files changed, 88 insertions, 1 deletions

diff --git a/arch/arm/mach-rmobile/memmap-gen3.c b/arch/arm/mach-rmobile/memmap-gen3.c
index 92c8f2e80db..7e29ccc351b 100644
--- a/arch/arm/mach-rmobile/memmap-gen3.c
+++ b/arch/arm/mach-rmobile/memmap-gen3.c
@@ -8,7 +8,9 @@
 #include <common.h>
 #include <asm/armv8/mmu.h>
 
-static struct mm_region gen3_mem_map[] = {
+#define GEN3_NR_REGIONS 16
+
+static struct mm_region gen3_mem_map[GEN3_NR_REGIONS] = {
 	{
 		.virt = 0x0UL,
 		.phys = 0x0UL,
@@ -42,3 +44,88 @@ static struct mm_region gen3_mem_map[] = {
 };
 
 struct mm_region *mem_map = gen3_mem_map;
+
+DECLARE_GLOBAL_DATA_PTR;
+
+void enable_caches(void)
+{
+	u64 start, size;
+	int bank, i = 0;
+
+	/* Create map for RPC access */
+	gen3_mem_map[i].virt = 0x0ULL;
+	gen3_mem_map[i].phys = 0x0ULL;
+	gen3_mem_map[i].size = 0x40000000ULL;
+	gen3_mem_map[i].attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRNE) |
+				PTE_BLOCK_NON_SHARE |
+				PTE_BLOCK_PXN | PTE_BLOCK_UXN;
+	i++;
+
+	/* Generate entires for DRAM in 32bit address space */
+	for (bank = 0; bank < CONFIG_NR_DRAM_BANKS; bank++) {
+		start = gd->bd->bi_dram[bank].start;
+		size = gd->bd->bi_dram[bank].size;
+
+		/* Skip empty DRAM banks */
+		if (!size)
+			continue;
+
+		/* Skip DRAM above 4 GiB */
+		if (start >> 32ULL)
+			continue;
+
+		/* Mark memory reserved by ATF as cacheable too. */
+		if (start == 0x48000000) {
+			start = 0x40000000ULL;
+			size += 0x08000000ULL;
+		}
+
+		gen3_mem_map[i].virt = start;
+		gen3_mem_map[i].phys = start;
+		gen3_mem_map[i].size = size;
+		gen3_mem_map[i].attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) |
+					PTE_BLOCK_INNER_SHARE;
+		i++;
+	}
+
+	/* Create map for register access */
+	gen3_mem_map[i].virt = 0xc0000000ULL;
+	gen3_mem_map[i].phys = 0xc0000000ULL;
+	gen3_mem_map[i].size = 0x40000000ULL;
+	gen3_mem_map[i].attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRNE) |
+				PTE_BLOCK_NON_SHARE |
+				PTE_BLOCK_PXN | PTE_BLOCK_UXN;
+	i++;
+
+	/* Generate entires for DRAM in 64bit address space */
+	for (bank = 0; bank < CONFIG_NR_DRAM_BANKS; bank++) {
+		start = gd->bd->bi_dram[bank].start;
+		size = gd->bd->bi_dram[bank].size;
+
+		/* Skip empty DRAM banks */
+		if (!size)
+			continue;
+
+		/* Skip DRAM below 4 GiB */
+		if (!(start >> 32ULL))
+			continue;
+
+		gen3_mem_map[i].virt = start;
+		gen3_mem_map[i].phys = start;
+		gen3_mem_map[i].size = size;
+		gen3_mem_map[i].attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) |
+					PTE_BLOCK_INNER_SHARE;
+		i++;
+	}
+
+	/* Zero out the remaining regions. */
+	for (; i < GEN3_NR_REGIONS; i++) {
+		gen3_mem_map[i].virt = 0;
+		gen3_mem_map[i].phys = 0;
+		gen3_mem_map[i].size = 0;
+		gen3_mem_map[i].attrs = 0;
+	}
+
+	icache_enable();
+	dcache_enable();
+}