ARM: mvebu: reserve the first 10 KB of each memory bank for suspend/resume

[karo-tx-linux.git] / arch / arm / mach-mvebu / board-v7.c

diff --git a/arch/arm/mach-mvebu/board-v7.c b/arch/arm/mach-mvebu/board-v7.c
index 6478626e3ff64c035e11ac69a290099c44d972a8..bc52231dfd1ceb2de794f545b16438dd19c0e222 100644 (file)
--- a/arch/arm/mach-mvebu/board-v7.c
+++ b/arch/arm/mach-mvebu/board-v7.c
@@ -16,10 +16,12 @@
 #include <linux/init.h>
 #include <linux/clk-provider.h>
 #include <linux/of_address.h>
+#include <linux/of_fdt.h>
 #include <linux/of_platform.h>
 #include <linux/io.h>
 #include <linux/clocksource.h>
 #include <linux/dma-mapping.h>
+#include <linux/memblock.h>
 #include <linux/mbus.h>
 #include <linux/signal.h>
 #include <linux/slab.h>
@@ -56,6 +58,54 @@ void __iomem *mvebu_get_scu_base(void)
        return scu_base;
 }
 
+/*
+ * When returning from suspend, the platform goes through the
+ * bootloader, which executes its DDR3 training code. This code has
+ * the unfortunate idea of using the first 10 KB of each DRAM bank to
+ * exercise the RAM and calculate the optimal timings. Therefore, this
+ * area of RAM is overwritten, and shouldn't be used by the kernel if
+ * suspend/resume is supported.
+ */
+
+#ifdef CONFIG_SUSPEND
+#define MVEBU_DDR_TRAINING_AREA_SZ (10 * SZ_1K)
+static int __init mvebu_scan_mem(unsigned long node, const char *uname,
+                                int depth, void *data)
+{
+       const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
+       const __be32 *reg, *endp;
+       int l;
+
+       if (type == NULL || strcmp(type, "memory"))
+               return 0;
+
+       reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
+       if (reg == NULL)
+               reg = of_get_flat_dt_prop(node, "reg", &l);
+       if (reg == NULL)
+               return 0;
+
+       endp = reg + (l / sizeof(__be32));
+       while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
+               u64 base, size;
+
+               base = dt_mem_next_cell(dt_root_addr_cells, &reg);
+               size = dt_mem_next_cell(dt_root_size_cells, &reg);
+
+               memblock_reserve(base, MVEBU_DDR_TRAINING_AREA_SZ);
+       }
+
+       return 0;
+}
+
+static void __init mvebu_memblock_reserve(void)
+{
+       of_scan_flat_dt(mvebu_scan_mem, NULL);
+}
+#else
+static void __init mvebu_memblock_reserve(void) {}
+#endif
+
 /*
  * Early versions of Armada 375 SoC have a bug where the BootROM
  * leaves an external data abort pending. The kernel is hit by this
@@ -210,6 +260,7 @@ DT_MACHINE_START(ARMADA_370_XP_DT, "Marvell Armada 370/XP (Device Tree)")
        .init_machine   = mvebu_dt_init,
        .init_irq       = mvebu_init_irq,
        .restart        = mvebu_restart,
+       .reserve        = mvebu_memblock_reserve,
        .dt_compat      = armada_370_xp_dt_compat,
 MACHINE_END