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-rw-r--r--target/linux/ramips/patches-5.10/325-mt7621-fix-memory-detect.patch58
1 files changed, 58 insertions, 0 deletions
diff --git a/target/linux/ramips/patches-5.10/325-mt7621-fix-memory-detect.patch b/target/linux/ramips/patches-5.10/325-mt7621-fix-memory-detect.patch
new file mode 100644
index 0000000000..ad072ec54e
--- /dev/null
+++ b/target/linux/ramips/patches-5.10/325-mt7621-fix-memory-detect.patch
@@ -0,0 +1,58 @@
+--- a/arch/mips/ralink/mt7621.c
++++ b/arch/mips/ralink/mt7621.c
+@@ -56,7 +56,9 @@
+ #define MT7621_GPIO_MODE_SDHCI_SHIFT 18
+ #define MT7621_GPIO_MODE_SDHCI_GPIO 1
+
+-static void *detect_magic __initdata = detect_memory_region;
++#define MT7621_MEM_TEST_PATTERN 0xaa5555aa
++
++static u32 detect_magic __initdata;
+
+ static struct rt2880_pmx_func uart1_grp[] = { FUNC("uart1", 0, 1, 2) };
+ static struct rt2880_pmx_func i2c_grp[] = { FUNC("i2c", 0, 3, 2) };
+@@ -142,24 +144,32 @@ static struct clk *__init mt7621_add_sys
+ return clk;
+ }
+
++static bool __init mt7621_addr_wraparound_test(phys_addr_t size)
++{
++ void *dm = (void *)KSEG1ADDR(&detect_magic);
++ if (CPHYSADDR(dm + size) >= MT7621_LOWMEM_MAX_SIZE)
++ return true;
++ __raw_writel(MT7621_MEM_TEST_PATTERN, dm);
++ if (__raw_readl(dm) != __raw_readl(dm + size))
++ return false;
++ __raw_writel(!MT7621_MEM_TEST_PATTERN, dm);
++ return __raw_readl(dm) == __raw_readl(dm + size);
++}
++
+ void __init mt7621_memory_detect(void)
+ {
+- void *dm = &detect_magic;
+ phys_addr_t size;
+
+- for (size = 32 * SZ_1M; size < 256 * SZ_1M; size <<= 1) {
+- if (!__builtin_memcmp(dm, dm + size, sizeof(detect_magic)))
+- break;
++ for (size = 32 * SZ_1M; size <= 256 * SZ_1M; size <<= 1) {
++ if (mt7621_addr_wraparound_test(size)) {
++ memblock_add(MT7621_LOWMEM_BASE, size);
++ return;
++ }
+ }
+
+- if ((size == 256 * SZ_1M) &&
+- (CPHYSADDR(dm + size) < MT7621_LOWMEM_MAX_SIZE) &&
+- __builtin_memcmp(dm, dm + size, sizeof(detect_magic))) {
+- memblock_add(MT7621_LOWMEM_BASE, MT7621_LOWMEM_MAX_SIZE);
+- memblock_add(MT7621_HIGHMEM_BASE, MT7621_HIGHMEM_SIZE);
+- } else {
+- memblock_add(MT7621_LOWMEM_BASE, size);
+- }
++ /* addr doesn't wrap around at dm + 256M, assume 512M memory. */
++ memblock_add(MT7621_LOWMEM_BASE, MT7621_LOWMEM_MAX_SIZE);
++ memblock_add(MT7621_HIGHMEM_BASE, MT7621_HIGHMEM_SIZE);
+ }
+
+ void __init ralink_clk_init(void)