i.MX: Add provisions to boot from IRAM

This commit add a very basic code to allow Barebox to be booted from
IRAM. Given that the amount of IRAM on most i.MX variants is
insufficient to contain a copy of Barebox with any reasonable degree
of functionality this code uses IRAM only as a temporary location and
eventually bootstraps from DRAM. But the presense of the intermediate
IRAM-only stage allows to add provisions to test the area of DRAM that
Barebox would be using to facilitate various testing scenarious.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 52 insertions, 0 deletions

diff --git a/arch/arm/mach-imx/xload.c b/arch/arm/mach-imx/xload.c
new file mode 100644
index 0000000000..16d56ab288
--- /dev/null
+++ b/arch/arm/mach-imx/xload.c
@@ -0,0 +1,52 @@
+#include <bootsource.h>
+#include <bootstrap.h>
+#include <common.h>
+#include <malloc.h>
+#include <init.h>
+#include <envfs.h>
+#include <linux/sizes.h>
+#include <fs.h>
+#include <io.h>
+
+#include <linux/clkdev.h>
+#include <linux/stat.h>
+#include <linux/clk.h>
+
+#include <mach/devices-imx51.h>
+
+static __noreturn int imx_xload(void)
+{
+	enum bootsource bootsource = bootsource_get();
+	void *buf;
+
+	switch (bootsource) {
+	case BOOTSOURCE_MMC:
+		pr_info("booting from MMC\n");
+		buf = bootstrap_read_disk("disk0.0", "fat");
+		break;
+	case BOOTSOURCE_SPI:
+		pr_info("booting from SPI\n");
+		buf = bootstrap_read_devfs("dataflash0", false,
+					   SZ_256K, SZ_1M, SZ_1M);
+		break;
+	default:
+		pr_err("unknown bootsource %d\n", bootsource);
+		hang();
+	}
+
+	if (!buf) {
+		pr_err("failed to load barebox.bin\n");
+		hang();
+	}
+
+	bootstrap_boot(buf, 0);
+
+	hang();
+}
+
+static int imx_devices_init(void)
+{
+	barebox_main = imx_xload;
+	return 0;
+}
+coredevice_initcall(imx_devices_init);