Hi Philipp:

On 2017年09月13日 03:30, Philipp Tomsich wrote:


On Mon, 11 Sep 2017, Andy Yan wrote:

Rockchip bootrom will enter download mode if it returns from
spl/tpl with a none-zero value and couldn't find a valid image
in the backup partition.
This patch provide a method to instruct the system to back to
bootrom download mode by checking the BROM_DOWNLOAD_FLAG register.
As the bootrom download function relys on some modules such as
interrupts, so we need to back to bootrom as early as possbile
before the tpl/tps code override the interrupt settings.

I was not aware that the TPL/SPL overrides interrupt settings. What exactly does this comment refer to?

For armv7, the VBAR and V in SCTLR(which should be 1 for rk3288 and zero for other arm32 platforms)
 are override in arch/cpu/armv7/start.S
    For armv8, I also find the VBAR related settings, but I didn't test it.
I am not sure is there any other settings in the TPL/SPL startup code that will override the default setting in bootrom(maybe mmu, cache and other feathers added to the startup code in the future, this is out of control), but the VBAR and V are indeed override on arm32 platforms. So I think back to bootrom download mode if the
flag is set before anything changed is a efficient way.


Signed-off-by: Andy Yan <[email protected]>
Reviewed-by: Kever Yang <[email protected]>
Acked-by: Philipp Tomsich <[email protected]>
---

arch/arm/include/asm/arch-rockchip/bootrom.h |  2 +-
arch/arm/mach-rockchip/Kconfig               | 13 +++++++
arch/arm/mach-rockchip/bootrom.c             |  2 +-
arch/arm/mach-rockchip/save_boot_param.S | 57 +++++++++++++++++++++++-----
4 files changed, 63 insertions(+), 11 deletions(-)

diff --git a/arch/arm/include/asm/arch-rockchip/bootrom.h b/arch/arm/include/asm/arch-rockchip/bootrom.h
index 92eb878..6ae3e94 100644
--- a/arch/arm/include/asm/arch-rockchip/bootrom.h
+++ b/arch/arm/include/asm/arch-rockchip/bootrom.h
@@ -22,6 +22,6 @@ void back_to_bootrom(void);
/**
 * Assembler component for the above (do not call this directly)
 */
-void _back_to_bootrom_s(void);
+void _back_to_bootrom_s(int mode);

Please add documentation for externally visible functions.
    Okay.


#endif
diff --git a/arch/arm/mach-rockchip/Kconfig b/arch/arm/mach-rockchip/Kconfig
index d9b25d5..3ab0c30 100644
--- a/arch/arm/mach-rockchip/Kconfig
+++ b/arch/arm/mach-rockchip/Kconfig
@@ -113,6 +113,7 @@ config ROCKCHIP_RK3399
    select SPL_SERIAL_SUPPORT
    select SPL_DRIVERS_MISC_SUPPORT
    select ENABLE_ARM_SOC_BOOT0_HOOK
+    select ROCKCHIP_BROM_HELPER
    select DEBUG_UART_BOARD_INIT
    help
      The Rockchip RK3399 is a ARM-based SoC with a dual-core Cortex-A72
@@ -149,6 +150,18 @@ config TPL_ROCKCHIP_BACK_TO_BROM
SPL will return to the boot rom, which will then load the U-Boot
          binary to keep going on.

+config ROCKCHIP_BACK_TO_BROM_DOWNLOAD_REG
+    hex "Bootrom download mode flag register address"
+    default 0x200081c8 if ROCKCHIP_RK3036
+    default 0xff730094 if ROCKCHIP_RK3288
+    default 0xff738200 if ROCKCHIP_RK3368
+    default 0xff320300 if ROCKCHIP_RK3399
+    default 0x10300580 if ROCKCHIP_RV1108
+    default 0x00

If this is not user-configurable (i.e. if it is a per-chip constant), we should define this in a header file. I would suggest to do the detection/mapping either in include/asm/arch-rockchip/bootrom.h or in a cpu-specific header that gets included from there.

Actually this is user-configuarable, we just chose a register that not be used by the system to pass the boot mode flag. And we also have boards that don't want to enable this function, so they can set the register address to 0. then we will ship
the mode check .

+    help
+      The Soc will return to bootrom download mode if this register set
+      to BOOTROM_DOWNLOAD_FLAG.

Documenting here what BOOTROM_DOWNLOAD_FLAG is or where it can be found would be very helpful to anyone coming across this in the future.

    okay

+
config ROCKCHIP_SPL_RESERVE_IRAM
    hex "Size of IRAM reserved in SPL"
    default 0x4000
diff --git a/arch/arm/mach-rockchip/bootrom.c b/arch/arm/mach-rockchip/bootrom.c
index 8380e4e..6f0d583 100644
--- a/arch/arm/mach-rockchip/bootrom.c
+++ b/arch/arm/mach-rockchip/bootrom.c
@@ -12,5 +12,5 @@ void back_to_bootrom(void)
#if CONFIG_IS_ENABLED(LIBCOMMON_SUPPORT)
    puts("Returning to boot ROM...\n");
#endif
-    _back_to_bootrom_s();
+    _back_to_bootrom_s(0);
}
diff --git a/arch/arm/mach-rockchip/save_boot_param.S b/arch/arm/mach-rockchip/save_boot_param.S
index 50fce20..f1bed0b 100644
--- a/arch/arm/mach-rockchip/save_boot_param.S
+++ b/arch/arm/mach-rockchip/save_boot_param.S
@@ -7,11 +7,25 @@

#include <linux/linkage.h>

+#define BACK_TO_BROM_DOWNLOAD_FLAG   0xEF08A53C

This looks like it should be defined in bootrom.h

    It has been move to boot-mode.h in new version.

+
#if defined(CONFIG_ARM64)
.globl    SAVE_SP_ADDR
SAVE_SP_ADDR:
    .quad 0

+ENTRY(check_back_to_brom_dnl_flag)
+    ldr    x8, =CONFIG_ROCKCHIP_BACK_TO_BROM_DOWNLOAD_REG
+    ldr    x9, [x8]
+    ldr    x0, =BACK_TO_BROM_DOWNLOAD_FLAG
+    cmp    x9, x0
+    b.ne    save_boot_params_ret
+    mov    x9, xzr
+    str    x9, [x8]    /* clear flag */
+ mov x0, #1 /* indicate the bootrom to enter download mode */
+    b    _back_to_bootrom_s

How does this ever get entered? If the download flag is already set prior to this code being executed, then the BROM would certainly not even come here?

BROM would not check the boot mode register, it only enter bootrom download mode if we return a non-zere value for it or it can't find a valid image from all the storage
device.

If you just always save the boot_params and check the download flag later from C code, then you could have this implemented in C. This will remove the need to write two separate assembly functions (for AArch64 and AArch32) and generally be more readable. Please revise.

We can't predict how many settings the TPL/SPL startup code changed now and future will affect the bootrom download function, So back to bootrom download mode before
anything been changed is a simple way.

+ENDPROC(check_back_to_brom_dnl_flag)
+
ENTRY(save_boot_params)
    sub    sp, sp, #0x60
    stp    x29, x30, [sp, #0x50]
@@ -23,14 +37,22 @@ ENTRY(save_boot_params)
    ldr    x8, =SAVE_SP_ADDR
    mov    x9, sp
    str    x9, [x8]
+#if CONFIG_ROCKCHIP_BACK_TO_BROM_DOWNLOAD_REG
+    b    check_back_to_brom_dnl_flag
+#else
    b    save_boot_params_ret  /* back to my caller */
+#endif

Please avoid the #if #else #endif here. Could you simply call into a function that handles this correctly for both cases?

 I have to skip the check if the REG address is zero.

However, this should fold back onto just the save_boot_params case anyway, if you can implement the checking function in C (as suggested above).

    Please see my explanation above.

ENDPROC(save_boot_params)

+/*
+ * x0: return value for bootrom, none-zero for bootrom download

typo: non-zero

+ *     mode and zero for normal boot mode
+ */
.globl _back_to_bootrom_s
ENTRY(_back_to_bootrom_s)
-    ldr    x0, =SAVE_SP_ADDR
-    ldr    x0, [x0]
-    mov    sp, x0
+    ldr    x1, =SAVE_SP_ADDR
+    ldr    x1, [x1]
+    mov    sp, x1
    ldp    x29, x30, [sp, #0x50]
    ldp    x27, x28, [sp, #0x40]
    ldp    x25, x26, [sp, #0x30]
@@ -38,7 +60,6 @@ ENTRY(_back_to_bootrom_s)
    ldp    x21, x22, [sp, #0x10]
    ldp    x19, x20, [sp]
    add    sp, sp, #0x60
-    mov    x0, xzr
    ret
ENDPROC(_back_to_bootrom_s)
#else
@@ -46,6 +67,18 @@ ENDPROC(_back_to_bootrom_s)
SAVE_SP_ADDR:
    .word 0

+ENTRY(check_back_to_brom_dnl_flag)
+    ldr    r0, =CONFIG_ROCKCHIP_BACK_TO_BROM_DOWNLOAD_REG
+    ldr    r1, [r0]
+    ldr    r2, =BACK_TO_BROM_DOWNLOAD_FLAG
+    cmp    r1, r2
+    bne    save_boot_params_ret
+    mov    r3, #0
+    str    r3, [r0]        @clear flag
+    mov    r0, #1          @indicate the bootrom to enter download mode
+    b    _back_to_bootrom_s
+ENDPROC(check_back_to_brom_dnl_flag)

See above: should be possible to do in C.

+
/*
 * void save_boot_params
 *
@@ -55,15 +88,21 @@ ENTRY(save_boot_params)
    push    {r1-r12, lr}
    ldr    r0, =SAVE_SP_ADDR
    str    sp, [r0]
-    b    save_boot_params_ret        @ back to my caller
+#if CONFIG_ROCKCHIP_BACK_TO_BROM_DOWNLOAD_REG
+    b    check_back_to_brom_dnl_flag
+#else
+    b       save_boot_params_ret
+#endif

See above.

ENDPROC(save_boot_params)

-
+/*
+ * r0: return value for bootrom, none-zero for bootrom download
+ *     mode and zero for normal boot mode
+ */
.globl _back_to_bootrom_s
ENTRY(_back_to_bootrom_s)
-    ldr    r0, =SAVE_SP_ADDR
-    ldr    sp, [r0]
-    mov    r0, #0
+    ldr    r1, =SAVE_SP_ADDR
+    ldr    sp, [r1]
    pop    {r1-r12, pc}
ENDPROC(_back_to_bootrom_s)
#endif






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