[PATCH] cfa10036: Retrieve the RAM size at runtime
Alexandre Belloni
alexandre.belloni at free-electrons.com
Thu Mar 21 11:36:38 EDT 2013
The cfa-10036 comes in two flavours, with either 128MB or 256MB of RAM
on it.
Since it's not stored anywhere, we need to runtime detect it by
introducing the cfa10036_get_ram_size function which is similar to
get_ram_size. As we run from RAM, we can then use _text and __bss_stop
to prevent poking in the barebox memory which is not supported on other
platforms.
Signed-off-by: Alexandre Belloni <alexandre.belloni at free-electrons.com>
Cc: Maxime Ripard <maxime.ripard at free-electrons.com>
---
arch/arm/boards/crystalfontz-cfa10036/cfa10036.c | 72 +++++++++++++++++++++-
1 file changed, 71 insertions(+), 1 deletion(-)
diff --git a/arch/arm/boards/crystalfontz-cfa10036/cfa10036.c b/arch/arm/boards/crystalfontz-cfa10036/cfa10036.c
index 1bc20cf..37cc17e 100644
--- a/arch/arm/boards/crystalfontz-cfa10036/cfa10036.c
+++ b/arch/arm/boards/crystalfontz-cfa10036/cfa10036.c
@@ -39,6 +39,8 @@
#include <asm/armlinux.h>
#include <asm/mmu.h>
+#include <asm-generic/sections.h>
+
#include <mach/fb.h>
#include <generated/mach-types.h>
@@ -90,9 +92,77 @@ static struct i2c_gpio_platform_data i2c_gpio_pdata = {
.udelay = 5, /* ~100 kHz */
};
+/*
+ * Copied from get_ram_size in common/memory.c
+ */
+long cfa10036_get_ram_size(volatile long *base, long maxsize)
+{
+ volatile long *addr;
+ long save[32];
+ long cnt;
+ long val;
+ long size;
+ int i = 0;
+
+ for (cnt = (maxsize / sizeof (long)) >> 1; cnt > 0; cnt >>= 1) {
+ addr = base + cnt; /* pointer arith! */
+
+ /*
+ * If we run get_ram_size from RAM, avoid poking into
+ * the Barebox code, and if the RAM at these address
+ * doesn't work, we will have trouble anyway...
+ */
+ if (addr > (long*)_text && addr < (long*)__bss_stop)
+ continue;
+
+ save[i++] = *addr;
+ *addr = ~cnt;
+ }
+
+ addr = base;
+ save[i] = *addr;
+ *addr = 0;
+
+ if ((val = *addr) != 0) {
+ /* Restore the original data before leaving the function.
+ */
+ *addr = save[i];
+ for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
+ addr = base + cnt;
+ *addr = save[--i];
+ }
+ return (0);
+ }
+
+ for (cnt = 1; cnt < maxsize / sizeof (long); cnt <<= 1) {
+ addr = base + cnt; /* pointer arith! */
+ if (addr > (long*)_text && addr < (long*)__bss_stop)
+ continue;
+
+ val = *addr;
+ *addr = save[--i];
+ if (val != ~cnt) {
+ size = cnt * sizeof (long);
+ /* Restore the original data before leaving the function.
+ */
+ for (cnt <<= 1; cnt < maxsize / sizeof (long); cnt <<= 1) {
+ addr = base + cnt;
+ if (addr > (long*)_text && addr < (long*)__bss_stop)
+ continue;
+
+ *addr = save[--i];
+ }
+ return (size);
+ }
+ }
+
+ return (maxsize);
+}
+
static int cfa10036_mem_init(void)
{
- arm_add_mem_device("ram0", IMX_MEMORY_BASE, 128 * 1024 * 1024);
+ arm_add_mem_device("ram0", IMX_MEMORY_BASE,
+ cfa10036_get_ram_size((volatile long int *)IMX_MEMORY_BASE, SZ_256M));
return 0;
}
--
1.7.10.4
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