The firmware running on the bcm2835 SoC's VideoCore CPU determines how
much of the system RAM is available for use by the ARM CPU. Previously,
U-Boot assumed that only 128MB was available, since this was the
smallest value configured by any public firmware. However, we can now
query the actual value at run-time from the firmware using the mbox
property protocol.
Signed-off-by: Stephen Warren <swar...@wwwdotorg.org>
---
v5: No change; merged patch series.
v4: No change; rebased.
v3: No change.
v2: Updated to use macros etc. added in v2 of mbox driver patch.
---
board/raspberrypi/rpi_b/rpi_b.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/board/raspberrypi/rpi_b/rpi_b.c b/board/raspberrypi/rpi_b/rpi_b.c
index 688b0aa..3c654a1 100644
--- a/board/raspberrypi/rpi_b/rpi_b.c
+++ b/board/raspberrypi/rpi_b/rpi_b.c
@@ -15,13 +15,32 @@
*/
#include <common.h>
+#include <asm/arch/mbox.h>
#include <asm/global_data.h>
DECLARE_GLOBAL_DATA_PTR;
+struct msg_get_arm_mem {
+ struct bcm2835_mbox_hdr hdr;
+ struct bcm2835_mbox_tag_get_arm_mem get_arm_mem;
+ u32 end_tag;
+};
+
int dram_init(void)
{
- gd->ram_size = CONFIG_SYS_SDRAM_SIZE;
+ ALLOC_ALIGN_BUFFER(struct msg_get_arm_mem, msg, 1, 16);
+ int ret;
+
+ BCM2835_MBOX_INIT_HDR(msg);
+ BCM2835_MBOX_INIT_TAG(&msg->get_arm_mem, GET_ARM_MEMORY);
+
+ ret = bcm2835_mbox_call_prop(BCM2835_MBOX_PROP_CHAN, &msg->hdr);
+ if (ret) {
+ printf("bcm2835: Could not query ARM memory size\n");
+ return -1;
+ }
+
+ gd->ram_size = msg->get_arm_mem.body.resp.mem_size;
return 0;
}
--
1.7.10.4
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