[U-Boot] mx28: booting u-boot via USB

[Fabio Estevam]

On 1/31/12, Matthias Fuchs <matthias.fuchs at esd.eu> wrote:

> The USB boot mechanism is not documented that detailed.
> Is it possible that the SPL code overwrites the bootroms ivt and
> in consequence crashes the bootrom's USB code? Any further ideas?

Completely untested, but please give it a try:

diff --git a/arch/arm/cpu/arm926ejs/mx28/spl_mem_init.c
b/arch/arm/cpu/arm926ejs/mx28/spl_mem_init.c
index 00493b8..313b5c7 100644
--- a/arch/arm/cpu/arm926ejs/mx28/spl_mem_init.c
+++ b/arch/arm/cpu/arm926ejs/mx28/spl_mem_init.c
@@ -201,8 +201,8 @@ void mx28_mem_init(void)
        writel(PINCTRL_EMI_DS_CTRL_DDR_MODE_DDR2,
                &pinctrl_regs->hw_pinctrl_emi_ds_ctrl_set);

-       /* Power up PLL0 */
-       writel(CLKCTRL_PLL0CTRL0_POWER,
+       /* Power up PLL0 and USB clocks */
+       writel(CLKCTRL_PLL0CTRL0_EN_USB_CLKS | CLKCTRL_PLL0CTRL0_POWER,
                &clkctrl_regs->hw_clkctrl_pll0ctrl0_set);

        early_delay(11000);
diff --git a/arch/arm/cpu/arm926ejs/mx28/spl_power_init.c
b/arch/arm/cpu/arm926ejs/mx28/spl_power_init.c
index 380b120..e55f552 100644
--- a/arch/arm/cpu/arm926ejs/mx28/spl_power_init.c
+++ b/arch/arm/cpu/arm926ejs/mx28/spl_power_init.c
@@ -45,7 +45,7 @@ void mx28_power_clock2pll(void)
        struct mx28_clkctrl_regs *clkctrl_regs =
                (struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;

-       writel(CLKCTRL_PLL0CTRL0_POWER,
+       writel(CLKCTRL_PLL0CTRL0_EN_USB_CLKS | CLKCTRL_PLL0CTRL0_POWER,
                &clkctrl_regs->hw_clkctrl_pll0ctrl0_set);
        early_delay(100);
        writel(CLKCTRL_CLKSEQ_BYPASS_CPU,