[U-Boot] [PATCH v1 1/2] imx: add macro to detect whether USB has been initialized

[Stefan Agner]

From: Stefan Agner <stefan.agner at toradex.com>

This macro allows to detect whether the boot ROM initialized USB
already (serial downloader). This is helpful to reliably detect
if the system has been recovered via USB serial downloader.

Signed-off-by: Stefan Agner <stefan.agner at toradex.com>
Acked-by: Marcel Ziswiler <marcel.ziswiler at toradex.com>
---
Hi Stefano,

I noted already in my initial post that detection of serial
downloader mode is somewhat brittle:
https://lists.denx.de/pipermail/u-boot/2017-August/301952.html

This came up quite fast now also for other boards:
https://www.mail-archive.com/u-boot@lists.denx.de/msg262234.html

We use this patches since quite some time. Also NXP uses this
detection method to start their mfgr tools... Altough a hack,
maybe we should still add it upstream?

--
Stefan


 arch/arm/include/asm/arch-mx6/imx-regs.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm/include/asm/arch-mx6/imx-regs.h b/arch/arm/include/asm/arch-mx6/imx-regs.h
index 86e267087a..895ef4de83 100644
--- a/arch/arm/include/asm/arch-mx6/imx-regs.h
+++ b/arch/arm/include/asm/arch-mx6/imx-regs.h
@@ -985,5 +985,12 @@ struct pwm_regs {
 	u32	pr;
 	u32	cnr;
 };
+
+/*
+ * If ROM fell back to USB recover mode, USBPH0_PWD will be clear to use USB
+ * If boot from the other mode, USB0_PWD will keep reset value
+ */
+#define	is_boot_from_usb(void) (!(readl(USB_PHY0_BASE_ADDR) & (1<<20)))
+
 #endif /* __ASSEMBLER__*/
 #endif /* __ASM_ARCH_MX6_IMX_REGS_H__ */
-- 
2.14.1