[U-Boot] [PATCH v2 5/8] omap-common: SYS_BOOT-based fallback boot device selection for peripheral boot

Paul Kocialkowski
2015-06-08T21:24:23Z

OMAP devices might boot from peripheral devices, such as UART or USB.
When that happens, the U-Boot SPL tries to boot the next stage (complete U-Boot)
from that peripheral device, but in most cases, this is not a valid boot device.

This introduces a fallback option that reads the SYS_BOOT pins, that are used by
the bootrom to determine which device to boot from. It is intended for the
SYS_BOOT value to be interpreted in the memory-preferred scheme, so that the
U-Boot SPL can load the next stage from a valid location.

Practically, this options allows loading the U-Boot SPL through USB and have it
load the next stage according to the memory device selected by SYS_BOOT instead
of stalling.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
---
arch/arm/cpu/armv7/omap-common/boot-common.c | 51 ++++++++++++++++++++++++----
arch/arm/include/asm/omap_common.h | 4 +++
2 files changed, 48 insertions(+), 7 deletions(-)

diff --git a/arch/arm/cpu/armv7/omap-common/boot-common.c b/arch/arm/cpu/armv7/omap-common/boot-common.c
index 944b6e4..8a7df89 100644
--- a/arch/arm/cpu/armv7/omap-common/boot-common.c
+++ b/arch/arm/cpu/armv7/omap-common/boot-common.c
@@ -21,6 +21,11 @@

DECLARE_GLOBAL_DATA_PTR;

+__weak u32 omap_sys_boot_device(void)
+{
+ return BOOT_DEVICE_NONE;
+}
+
void save_omap_boot_params(void)
{
u32 boot_params = *((u32 *)OMAP_SRAM_SCRATCH_BOOT_PARAMS);
@@ -34,9 +39,10 @@ void save_omap_boot_params(void)

omap_boot_params = (struct omap_boot_parameters *)boot_params;

- /* Boot device */
-
boot_device = omap_boot_params->boot_device;
+ boot_mode = MMCSD_MODE_UNDEFINED;
+
+ /* Boot device */

#ifdef BOOT_DEVICE_NAND_I2C
/*
@@ -58,16 +64,38 @@ void save_omap_boot_params(void)
if (boot_device == BOOT_DEVICE_QSPI_4)
boot_device = BOOT_DEVICE_SPI;
#endif
+#if (defined(BOOT_DEVICE_UART) && !defined(CONFIG_SPL_YMODEM_SUPPORT)) || \
+ (defined(BOOT_DEVICE_USB) && !defined(CONFIG_SPL_USB_SUPPORT))
+ /*
+ * When booting from peripheral booting, the boot device is not usable
+ * as-is (unless there is support for it), so the boot device is instead
+ * figured out using the SYS_BOOT pins.
+ */
+ switch (boot_device) {
+#ifdef BOOT_DEVICE_UART
+ case BOOT_DEVICE_UART:
+#endif
+#ifdef BOOT_DEVICE_USB
+ case BOOT_DEVICE_USB:
+#endif
+ boot_device = omap_sys_boot_device();
+
+ /* MMC raw mode will fallback to FS mode. */
+ if ((boot_device >= MMC_BOOT_DEVICES_START) &&
+ (boot_device <= MMC_BOOT_DEVICES_END))
+ boot_mode = MMCSD_MODE_RAW;
+
+ break;
+ }
+#endif

gd->arch.omap_boot_device = boot_device;

/* Boot mode */

- boot_mode = MMCSD_MODE_UNDEFINED;
-
+#ifdef CONFIG_OMAP34XX
if ((boot_device >= MMC_BOOT_DEVICES_START) &&
(boot_device <= MMC_BOOT_DEVICES_END)) {
-#ifdef CONFIG_OMAP34XX
switch (boot_device) {
case BOOT_DEVICE_MMC1:
boot_mode = MMCSD_MODE_FS;
@@ -76,7 +104,16 @@ void save_omap_boot_params(void)
boot_mode = MMCSD_MODE_RAW;
break;
}
+ }
#else
+ /*
+ * If the boot device was dynamically changed and doesn't match what
+ * the bootrom initially booted, we cannot use the boot device
+ * descriptor to figure out te boot mode.
+ */
+ if ((boot_device == omap_boot_params->boot_device) &&
+ (boot_device >= MMC_BOOT_DEVICES_START) &&
+ (boot_device <= MMC_BOOT_DEVICES_END)) {
boot_params = omap_boot_params->boot_device_descriptor;
if ((boot_params < NON_SECURE_SRAM_START) ||
(boot_params > NON_SECURE_SRAM_END))
@@ -92,12 +129,12 @@ void save_omap_boot_params(void)
if (boot_mode != MMCSD_MODE_FS &&
boot_mode != MMCSD_MODE_RAW)
#ifdef CONFIG_SUPPORT_EMMC_BOOT
- boot_mode = MMCSD_MODE_EMMCBOOT
+ boot_mode = MMCSD_MODE_EMMCBOOT;
#else
boot_mode = MMCSD_MODE_UNDEFINED;
#endif
-#endif
}
+#endif

gd->arch.omap_boot_mode = boot_mode;

diff --git a/arch/arm/include/asm/omap_common.h b/arch/arm/include/asm/omap_common.h
index e8c502c..7733311 100644
--- a/arch/arm/include/asm/omap_common.h
+++ b/arch/arm/include/asm/omap_common.h
@@ -682,4 +682,8 @@ static inline u8 is_dra7xx(void)
#define CH_FLAGS_CHFLASH (1 << 2)
#define CH_FLAGS_CHMMCSD (1 << 3)

+#ifndef __ASSEMBLY__
+u32 omap_sys_boot_device(void);
+#endif
+
#endif /* _OMAP_COMMON_H_ */
--
1.9.1