RealView: Add sparsemem support for the RealView PBX platform

The RealView PBX board has two 512MB blocks of memory - one at
0x70000000 (with 256MB mirror at 0) and another at 0x20000000. Only the
block at 0x70000000 (or the mirror at 0) may be used for DMA (e.g.
framebuffer). This patch adds the sparsemem definitions to allow the use
of all the memory split as follows:

  256MB @ 0x00000000 (ZONE_DMA)
  512MB @ 0x20000000 (ZONE_NORMAL)
  256MB @ 0x80000000 (ZONE_NORMAL)

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

4 files changed, 94 insertions, 3 deletions

diff --git a/arch/arm/mach-realview/Kconfig b/arch/arm/mach-realview/Kconfig
index dfc9b0bc6eb2..c48e1f2c3349 100644
--- a/arch/arm/mach-realview/Kconfig
+++ b/arch/arm/mach-realview/Kconfig
@@ -70,6 +70,8 @@ config MACH_REALVIEW_PBX
         bool "Support RealView/PBX platform"
         select ARM_GIC
         select HAVE_PATA_PLATFORM
+        select ARCH_SPARSEMEM_ENABLE if CPU_V7 && !HIGH_PHYS_OFFSET
+        select ZONE_DMA if SPARSEMEM
         help
           Include support for the ARM(R) RealView PBX platform.
 
@@ -82,6 +84,7 @@ config REALVIEW_HIGH_PHYS_OFFSET
           0x70000000, 256MB of which being mirrored at 0x00000000. If
           the board supports 512MB of RAM, this option allows the
           memory to be accessed contiguously at the high physical
-          offset.
+          offset. On the PBX board, disabling this option allows 1GB of
+          RAM to be used with SPARSEMEM.
 
 endmenu
diff --git a/arch/arm/mach-realview/core.c b/arch/arm/mach-realview/core.c
index c21b0fd39652..9f293438e020 100644
--- a/arch/arm/mach-realview/core.c
+++ b/arch/arm/mach-realview/core.c
@@ -59,6 +59,25 @@
 /* used by entry-macro.S and platsmp.c */
 void __iomem *gic_cpu_base_addr;
 
+#ifdef CONFIG_ZONE_DMA
+/*
+ * Adjust the zones if there are restrictions for DMA access.
+ */
+void __init realview_adjust_zones(int node, unsigned long *size,
+                                  unsigned long *hole)
+{
+        unsigned long dma_size = SZ_256M >> PAGE_SHIFT;
+
+        if (!machine_is_realview_pbx() || node || (size[0] <= dma_size))
+                return;
+
+        size[ZONE_NORMAL] = size[0] - dma_size;
+        size[ZONE_DMA] = dma_size;
+        hole[ZONE_NORMAL] = hole[0];
+        hole[ZONE_DMA] = 0;
+}
+#endif
+
 /*
  * This is the RealView sched_clock implementation.  This has
  * a resolution of 41.7ns, and a maximum value of about 179s.
@@ -543,7 +562,7 @@ static int realview_clcd_setup(struct clcd_fb *fb)
         fb->panel               = realview_clcd_panel();
 
         fb->fb.screen_base = dma_alloc_writecombine(&fb->dev->dev, framesize,
-                                                    &dma, GFP_KERNEL);
+                                                    &dma, GFP_KERNEL | GFP_DMA);
         if (!fb->fb.screen_base) {
                 printk(KERN_ERR "CLCD: unable to map framebuffer\n");
                 return -ENOMEM;
diff --git a/arch/arm/mach-realview/include/mach/memory.h b/arch/arm/mach-realview/include/mach/memory.h
index 293c30025e7e..2417bbcf97fd 100644
--- a/arch/arm/mach-realview/include/mach/memory.h
+++ b/arch/arm/mach-realview/include/mach/memory.h
@@ -29,4 +29,53 @@
 #define PHYS_OFFSET             UL(0x00000000)
 #endif
 
+#if !defined(__ASSEMBLY__) && defined(CONFIG_ZONE_DMA)
+extern void realview_adjust_zones(int node, unsigned long *size,
+                                  unsigned long *hole);
+#define arch_adjust_zones(node, size, hole) \
+        realview_adjust_zones(node, size, hole)
+
+#define ISA_DMA_THRESHOLD       (PHYS_OFFSET + SZ_256M - 1)
+#define MAX_DMA_ADDRESS         (PAGE_OFFSET + SZ_256M)
+#endif
+
+#ifdef CONFIG_SPARSEMEM
+
+/*
+ * Sparsemem definitions for RealView PBX.
+ *
+ * The RealView PBX board has another block of 512MB of RAM at 0x20000000,
+ * however only the block at 0x70000000 (or the 256MB mirror at 0x00000000)
+ * may be used for DMA.
+ *
+ * The macros below define a section size of 256MB and a non-linear virtual to
+ * physical mapping:
+ *
+ * 256MB @ 0x00000000 -> PAGE_OFFSET
+ * 512MB @ 0x20000000 -> PAGE_OFFSET + 0x10000000
+ * 256MB @ 0x80000000 -> PAGE_OFFSET + 0x30000000
+ */
+#ifdef CONFIG_REALVIEW_HIGH_PHYS_OFFSET
+#error "SPARSEMEM not available with REALVIEW_HIGH_PHYS_OFFSET"
+#endif
+
+#define MAX_PHYSMEM_BITS        32
+#define SECTION_SIZE_BITS       28
+
+/* bank page offsets */
+#define PAGE_OFFSET1    (PAGE_OFFSET + 0x10000000)
+#define PAGE_OFFSET2    (PAGE_OFFSET + 0x30000000)
+
+#define __phys_to_virt(phys)                                            \
+        ((phys) >= 0x80000000 ? (phys) - 0x80000000 + PAGE_OFFSET2 :    \
+         (phys) >= 0x20000000 ? (phys) - 0x20000000 + PAGE_OFFSET1 :    \
+         (phys) + PAGE_OFFSET)
+
+#define __virt_to_phys(virt)                                            \
+         ((virt) >= PAGE_OFFSET2 ? (virt) - PAGE_OFFSET2 + 0x80000000 : \
+          (virt) >= PAGE_OFFSET1 ? (virt) - PAGE_OFFSET1 + 0x20000000 : \
+          (virt) - PAGE_OFFSET)
+
+#endif  /* CONFIG_SPARSEMEM */
+
 #endif
diff --git a/arch/arm/mach-realview/realview_pbx.c b/arch/arm/mach-realview/realview_pbx.c
index 5d09d8b4a1cb..ec39488e2b42 100644
--- a/arch/arm/mach-realview/realview_pbx.c
+++ b/arch/arm/mach-realview/realview_pbx.c
@@ -304,6 +304,26 @@ static struct sys_timer realview_pbx_timer = {
         .init           = realview_pbx_timer_init,
 };
 
+static void realview_pbx_fixup(struct machine_desc *mdesc, struct tag *tags,
+                               char **from, struct meminfo *meminfo)
+{
+#ifdef CONFIG_SPARSEMEM
+        /*
+         * Memory configuration with SPARSEMEM enabled on RealView PBX (see
+         * asm/mach/memory.h for more information).
+         */
+        meminfo->bank[0].start = 0;
+        meminfo->bank[0].size = SZ_256M;
+        meminfo->bank[1].start = 0x20000000;
+        meminfo->bank[1].size = SZ_512M;
+        meminfo->bank[2].start = 0x80000000;
+        meminfo->bank[2].size = SZ_256M;
+        meminfo->nr_banks = 3;
+#else
+        realview_fixup(mdesc, tags, from, meminfo);
+#endif
+}
+
 static void __init realview_pbx_init(void)
 {
         int i;
@@ -345,7 +365,7 @@ MACHINE_START(REALVIEW_PBX, "ARM-RealView PBX")
         .phys_io        = REALVIEW_PBX_UART0_BASE,
         .io_pg_offst    = (IO_ADDRESS(REALVIEW_PBX_UART0_BASE) >> 18) & 0xfffc,
         .boot_params    = PHYS_OFFSET + 0x00000100,
-        .fixup          = realview_fixup,
+        .fixup          = realview_pbx_fixup,
         .map_io         = realview_pbx_map_io,
         .init_irq       = gic_init_irq,
         .timer          = &realview_pbx_timer,