Linux/AM3359: DDR frequency not changing

Hello,

Please refer to the following page as a reference.

Regards,
Krunal

Hi Krunal,

                   I already went through that document several times before.In the document its mentioned that  to change ddr frequency i have to use this function:

config_ddr(303, &ioregs_evmsk, &ddr3_icev2_data,
                           &ddr3_icev2_cmd_ctrl_data, &ddr3_icev2_emif_reg_data,
                           0);

              As I mentioned before the function which is supposed to use the 303 value is blank.

Im attaching the code segment here:

void __weak ddr_pll_config(unsigned int ddrpll_m)
{

}

void config_ddr(unsigned int pll, const struct ctrl_ioregs *ioregs,
                const struct ddr_data *data, const struct cmd_control *ctrl,
                const struct emif_regs *regs, int nr)
{
        ddr_pll_config(pll);
        config_vtp(nr);
        config_cmd_ctrl(ctrl, nr);

        config_ddr_data(data, nr);

#ifdef CONFIG_AM33XX

        config_io_ctrl(ioregs);

        /* Set CKE to be controlled by EMIF/DDR PHY */
        writel(DDR_CKE_CTRL_NORMAL, &ddrctrl->ddrckectrl);

#endif
#ifdef CONFIG_AM43XX
        writel(readl(&cm_device->cm_dll_ctrl) & ~0x1, &cm_device->cm_dll_ctrl);
        while ((readl(&cm_device->cm_dll_ctrl) & CM_DLL_READYST) == 0)
                ;

        config_io_ctrl(ioregs);

        /* Set CKE to be controlled by EMIF/DDR PHY */
        writel(DDR_CKE_CTRL_NORMAL, &ddrctrl->ddrckectrl);

        if (emif_sdram_type(regs->sdram_config) == EMIF_SDRAM_TYPE_DDR3)
#ifndef CONFIG_SPL_RTC_ONLY_SUPPORT
                /* Allow EMIF to control DDR_RESET */

                writel(0x00000000, &ddrctrl->ddrioctrl);
#else
                /* Override EMIF DDR_RESET control */
                writel(0x80000000, &ddrctrl->ddrioctrl);
#endif /* CONFIG_SPL_RTC_ONLY_SUPPORT */
#endif


        /* Program EMIF instance */
        config_ddr_phy(regs, nr);

        set_sdram_timings(regs, nr);
        if (get_emif_rev(EMIF1_BASE) == EMIF_4D5)

       config_sdram_emif4d5(regs, nr);
        else
                config_sdram(regs, nr);
}

Regards,

Murugan S

Please add a printf inside the config_ddr() function to print out the pll parameter that was passed to it.  You're correct that to change the DDR frequency, you simply need to pass the desired frequency to the config_ddr() function.  I expect you have a mistake somewhere with respect to how the function is being called (e.g. being called multiple times or being called with wrong frequency, etc.).

Hi Brad,

                         Thanks for your input.But my doubt is:

1)DDR frequency is set using this function:

config_ddr(303, &ioregs_evmsk, &ddr3_icev2_data,&ddr3_icev2_cmd_ctrl_data, &ddr3_icev2_emif_reg_data, 0);

2)Inside config_ddr() function pll frequency(303 in my case) is used by  ddr_pll_config(pll) function.

3)But ddr_pll_config(pll) is an empty function.It does nothing.

                  This is my observation.Did i miss anything?

Regards,

Murugan S