ARM: zynq: Reserve not DMAable space in front of the kernel

Reserve space from 0x0 - __pa(swapper_pg_dir),
if kernel is loaded from 0, which is not DMAable.
It is causing problem with MMC driver and others
which want to add dma buffers to this space.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Kevin Hilman <khilman@linaro.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/arm/mach-zynq/common.c b/arch/arm/mach-zynq/common.c
index 1db2a5ca9ab8..8c09a8393fb6 100644
--- a/arch/arm/mach-zynq/common.c
+++ b/arch/arm/mach-zynq/common.c
@@ -25,6 +25,7 @@
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/of.h>
+#include <linux/memblock.h>
 #include <linux/irqchip.h>
 #include <linux/irqchip/arm-gic.h>
 
@@ -41,6 +42,18 @@
 
 void __iomem *zynq_scu_base;
 
+/**
+ * zynq_memory_init - Initialize special memory
+ *
+ * We need to stop things allocating the low memory as DMA can't work in
+ * the 1st 512K of memory.
+ */
+static void __init zynq_memory_init(void)
+{
+        if (!__pa(PAGE_OFFSET))
+                memblock_reserve(__pa(PAGE_OFFSET), __pa(swapper_pg_dir));
+}
+
 static struct platform_device zynq_cpuidle_device = {
         .name = "cpuidle-zynq",
 };
@@ -117,5 +130,6 @@ DT_MACHINE_START(XILINX_EP107, "Xilinx Zynq Platform")
         .init_machine   = zynq_init_machine,
         .init_time      = zynq_timer_init,
         .dt_compat      = zynq_dt_match,
+        .reserve        = zynq_memory_init,
         .restart        = zynq_system_reset,
 MACHINE_END