Hi Vincent,
On 22/05/2015 16:52, Vincent Stehlé wrote:
Add a detection at runtime of the boot from USB on i.MX6, and invalidate the D-cache only in that case.
The USB boot detection method is taken from Freescale u-boot commit 1309b1ed78b3 ("ENGR00315499-8 Auto check if boot from usb").
This repairs u-boot when it is built with CONFIG_SKIP_LOWLEVEL_INIT defined, and is booted from another u-boot, which booted from SD card, for example.
Please help me to find the use case. I searched in all i.MX6 boards in mainline, but none of them is setting CONFIG_SKIP_LOWLEVEL_INIT. Can you tell me on which board there is this issue ?
Signed-off-by: Vincent Stehlé vincent.stehle@freescale.com Cc: Stefano Babic sbabic@denx.de Cc: Fabio Estevam fabio.estevam@freescale.com Cc: Frank Li Frank.li@freescale.com Cc: Nitin Garg nitin.garg@freescale.com
arch/arm/cpu/armv7/mx6/soc.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/arch/arm/cpu/armv7/mx6/soc.c b/arch/arm/cpu/armv7/mx6/soc.c index 21ef9d0..774f078 100644 --- a/arch/arm/cpu/armv7/mx6/soc.c +++ b/arch/arm/cpu/armv7/mx6/soc.c @@ -350,6 +350,18 @@ int board_postclk_init(void) return 0; }
+/*
- Determine if we booted from USB.
- We look at the USBPH0_PWD0.RXPWDRX register to determine if the USB
- PHY is powered on or off. If the USB PHY is turned on, we assume that
- the ROM booted us from USB.
- */
+static bool is_boot_from_usb(void) +{
- return !(readl(USB_PHY0_BASE_ADDR) & (1<<20));
+}
This looks like a hack. I understand this can work in your case, but can we set as general case ? You check power for PHY0, but what about if a board is using PHY1 ?
Anyway, is it not possible to get the boot storage from the SRC ?
#ifndef CONFIG_SYS_DCACHE_OFF void enable_caches(void) { @@ -360,7 +372,8 @@ void enable_caches(void) #endif
/* Avoid random hang when download by usb */
- invalidate_dcache_all();
- if (is_boot_from_usb())
invalidate_dcache_all();
I cannot understand well this. The correct implementation seems correct to me. And if you have issues booting with USB, why are you changing the behavior in all other cases *except* booting from USB, where you rely on the current implementation invalidating the cache ?
Best regards, Stefano Babic