[U-Boot] Implementing spl_start_uboot() for directly booting linux
Hello,
I am trying to directly boot the kernel i.e without u-boot, on my Xilinx Zynq based microzed board.
I understand that for that I must implement the function spl_start_uboot() in spl.c
Right now the definition is:
#ifdef CONFIG_SPL_OS_BOOT int spl_start_uboot(void) { /* boot linux */ return 0; } #endif
Given here: https://github.com/Xilinx/u-boot-xlnx/blob/2a0536fa48db1fc5332e3cd33b846d0da...
Can someone explain how to implement this function for directly booting the kernel? Actually till now all the boards I have searched have not implemented this function, So if you can provide any example board implementation , it would give me a clear picture of how to do this for my zynq board.
Thanks in advance,
Abdul Basit
Hi Abdul,
On 30/07/2014 10:21, Heshsham Abdul Basit wrote:
Hello,
I am trying to directly boot the kernel i.e without u-boot, on my Xilinx Zynq based microzed board.
I understand that for that I must implement the function spl_start_uboot() in spl.c
Right now the definition is:
#ifdef CONFIG_SPL_OS_BOOT int spl_start_uboot(void) { /* boot linux */ return 0; } #endif
Given here: https://github.com/Xilinx/u-boot-xlnx/blob/2a0536fa48db1fc5332e3cd33b846d0da...
Anyway, you are not using mainline. Please stick with the sources on u-boot mainline to get help here.
Can someone explain how to implement this function for directly booting the kernel? Actually till now all the boards I have searched have not implemented this function,
This means you have not deeply searched. Check for example board/technexion/twister/twister.c:
int spl_start_uboot(void) { int val = 0; if (!gpio_request(SPL_OS_BOOT_KEY, "U-Boot key")) { gpio_direction_input(SPL_OS_BOOT_KEY); val = gpio_get_value(SPL_OS_BOOT_KEY); gpio_free(SPL_OS_BOOT_KEY); } return val; }
On this board, the decision which image to boot is taken by looking at a GPIO (switch on the board). Of course, you can implement the way you need based on your hardware.
Best regards, Stefano Babic
On 30 July 2014 13:56, Stefano Babic sbabic@denx.de wrote:
Hi Abdul,
On 30/07/2014 10:21, Heshsham Abdul Basit wrote:
Hello,
I am trying to directly boot the kernel i.e without u-boot, on my Xilinx Zynq based microzed board.
I understand that for that I must implement the function spl_start_uboot() in spl.c
Right now the definition is:
#ifdef CONFIG_SPL_OS_BOOT int spl_start_uboot(void) { /* boot linux */ return 0; } #endif
Given here: https://github.com/Xilinx/u-boot-xlnx/blob/2a0536fa48db1fc5332e3cd33b846d0da...
Anyway, you are not using mainline. Please stick with the sources on u-boot mainline to get help here.
OK.
Can someone explain how to implement this function for directly booting the kernel? Actually till now all the boards I have searched have not implemented this function,
This means you have not deeply searched. Check for example board/technexion/twister/twister.c:
int spl_start_uboot(void) { int val = 0; if (!gpio_request(SPL_OS_BOOT_KEY, "U-Boot key")) { gpio_direction_input(SPL_OS_BOOT_KEY); val = gpio_get_value(SPL_OS_BOOT_KEY); gpio_free(SPL_OS_BOOT_KEY); } return val; }
Thanks. I missed this.
On this board, the decision which image to boot is taken by looking at a GPIO (switch on the board). Of course, you can implement the way you need based on your hardware.
Will give it a try.
Best regards, Stefano Babic
Thanks.
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participants (2)
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Heshsham Abdul Basit -
Stefano Babic