arm: mach-imx: cpu: add is_usb_boot

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

arch/arm/include/asm/arch-mx5/sys_proto.h

@@ -8,4 +8,5 @@
 
 #include <asm/mach-imx/sys_proto.h>
 
+bool is_usb_boot(void);
 #endif /* __SYS_PROTO_IMX5_ */

arch/arm/include/asm/arch-mx6/sys_proto.h

@@ -30,4 +30,5 @@ static inline void iomuxc_set_rgmii_io_voltage(int io_vol)
 	__raw_writel(io_vol, IOMUXC_SW_PAD_CTL_GRP_DDR_TYPE_RGMII);
 }
 
+bool is_usb_boot(void);
 #endif /* __SYS_PROTO_IMX6_ */

arch/arm/include/asm/arch-mx7/sys_proto.h

@@ -9,5 +9,6 @@
 
 void set_wdog_reset(struct wdog_regs *wdog);
 enum boot_device get_boot_device(void);
+bool is_usb_boot(void);
 
 #endif /* __SYS_PROTO_IMX7_ */

arch/arm/mach-imx/cpu.c

@@ -471,6 +471,47 @@ enum boot_device get_boot_device(void)
 
 	return boot_dev;
 }
+
+bool is_usb_boot(void)
+{
+	return get_boot_device() == USB_BOOT;
+}
+#elif defined(CONFIG_MX6)
+bool is_usb_boot(void)
+{
+	unsigned int bmode = readl(&src_base->sbmr2);
+	u32 reg;
+
+	/*
+	 * Check for BMODE if serial downloader is enabled
+	 * BOOT_MODE - see IMX6DQRM Table 8-1
+	 */
+	if (((bmode >> 24) & 0x03) == 0x01) /* Serial Downloader */
+		return true;
+
+	/*
+	 * The above method does not detect that the boot ROM used
+	 * serial downloader in case the boot ROM decided to use the
+	 * serial downloader as a fall back (primary boot source failed).
+	 *
+	 * Infer that the boot ROM used the USB serial downloader by
+	 * checking whether the USB PHY is currently active... This
+	 * assumes that SPL did not (yet) initialize the USB PHY...
+	 */
+	if (is_usbotg_phy_active())
+		return true;
+
+	reg = (imx6_src_get_boot_mode() & IMX6_BMODE_MASK) >> IMX6_BMODE_SHIFT;
+
+	if (reg == IMX6_BMODE_RESERVED)
+                return true;
+	return false;
+}
+#else
+bool is_usb_boot(void)
+{
+	return false;
+}
 #endif
 
 #ifdef CONFIG_NXP_BOARD_REVISION

arch/arm/mach-imx/mx8m/soc.c

@@ -167,11 +167,6 @@ int arch_cpu_init(void)
 	return 0;
 }
 
-bool is_usb_boot(void)
-{
-	return get_boot_device() == USB_BOOT;
-}
-
 #ifdef CONFIG_OF_SYSTEM_SETUP
 int ft_system_setup(void *blob, bd_t *bd)
 {