[U-Boot] [PATCH v3] arm: socfpga: fix issue with warm reset when CSEL is 0

[Marek Vasut]

On 02/18/2017 02:34 AM, Dalon Westergreen wrote:
> When CSEL=0x0 the socfpga bootrom does not touch the clock
> configuration for the device.  This can lead to a boot failure
> on warm resets. This patch disables warm resets when CSEL=0.
> This results in the clock and pll configurations being reset
> on any reset issued when CSEL=0.
> 
> Signed-off-by: Dalon Westergreen <dwesterg at gmail.com>

What about my suggestion for V2 about just loading function pointer into
the reset jump address register ?

btw --- missing before the changelog, without it the changelog will land
in git history.

> Changes in v3:
>  - Change implementation to rely on cold reset for CSEL=0. Which
>    is a much simpler approach to dealing with this special case
>    during boot.
> Changes in v2:
>  - Fix checkpatch issues predominently due to whitespace issues
> ---
>  arch/arm/mach-socfpga/include/mach/system_manager.h |  3 +++
>  arch/arm/mach-socfpga/misc.c                        | 13 ++++++++++++-
>  2 files changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mach-socfpga/include/mach/system_manager.h b/arch/arm/mach-socfpga/include/mach/system_manager.h
> index c45edea..c9c0b33 100644
> --- a/arch/arm/mach-socfpga/include/mach/system_manager.h
> +++ b/arch/arm/mach-socfpga/include/mach/system_manager.h
> @@ -137,6 +137,9 @@ struct socfpga_system_manager {
>  
>  #define SYSMGR_SDMMC_DRVSEL_SHIFT	0
>  
> +#define SYSMGR_BOOTINFO_CSEL_MASK	0x18
> +#define SYSMGR_BOOTINFO_CSEL_LSB	3
> +
>  /* EMAC Group Bit definitions */
>  #define SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_GMII_MII	0x0
>  #define SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_RGMII		0x1
> diff --git a/arch/arm/mach-socfpga/misc.c b/arch/arm/mach-socfpga/misc.c
> index dd6b53b..9792138 100644
> --- a/arch/arm/mach-socfpga/misc.c
> +++ b/arch/arm/mach-socfpga/misc.c
> @@ -356,6 +356,7 @@ static uint32_t iswgrp_handoff[8];
>  int arch_early_init_r(void)
>  {
>  	int i;
> +	unsigned int csel;
>  
>  	/*
>  	 * Write magic value into magic register to unlock support for
> @@ -363,8 +364,18 @@ int arch_early_init_r(void)
>  	 * value to be written into the register by the bootloader, so
>  	 * to support that old code, we write it here instead of in the
>  	 * reset_cpu() function just before resetting the CPU.
> +	 *
> +	 * For CSEL = 0 we do not want to enable warm resets to ensure that
> +	 * on reset the clocks and plls are reset to their default states as
> +	 * the bootrom, for CSEL=0, leaves the clocks untouched.  If the clocks
> +	 * and plls are not reset, the bootrom will fail to load the spl image.
>  	 */
> -	writel(0xae9efebc, &sysmgr_regs->romcodegrp_warmramgrp_enable);
> +
> +	csel = (readl(&sysmgr_regs->bootinfo) & SYSMGR_BOOTINFO_CSEL_MASK) >>
> +		SYSMGR_BOOTINFO_CSEL_LSB;
> +
> +	if (csel)
> +		writel(0xae9efebc, &sysmgr_regs->romcodegrp_warmramgrp_enable);
>  
>  	for (i = 0; i < 8; i++)	/* Cache initial SW setting regs */
>  		iswgrp_handoff[i] = readl(&sysmgr_regs->iswgrp_handoff[i]);
> 


-- 
Best regards,
Marek Vasut