disable unused clocks

Mike,

Let us first focus on PCIe. In u-boot, unless you configure to boot from PCIe, the PCIe is disabled by default. Make sure the below registers have these values:

SERDES_REFCLK_CTRL/0x48140E24 = 0x3
PCIE_PLLCFG0/0x481406D8 = 0x40007000
CM_DEFAULT_PCI_CLKCTRL/0x48180578 = 0x00070000
CM_DEFAULT_PCI_CLKSTCTRL/0x48180510 = 0x00000001

While in linux kernel, PCIe module is enabled by default in the below file and functions:

linux-kernel/arch/arm/mach-omap2/devices.c - ti814x_pcie_pllcfg() and ti81xx_init_pcie()

You can remove this code or modify it to get the right values in the above registers.

static int __init omap2_init_devices(void)
{

#ifdef CONFIG_ARCH_TI81XX
    if (cpu_is_ti814x()) {
        /* Init PCIe,SATA PLL here, before invoking respective init*/
        //ti814x_pcie_pllcfg();
        //if(!cpu_is_ti811x())
            //ti814x_sata_pllcfg();
    }

    ti81xx_ethernet_init();
    //ti81xx_init_pcie();

BR
Pavel

Hi Pavel,

Thanks for the response, I have fixed the disabling of clocks as per your suggestion but how do I disable the clocks for SGX, NEON and DSP ?

are they enabled in u-boot or linux ?

Thanks And Regards

Mike

Mike,

Regarding SATA, you should have the below values:

CM_DEFAULT_SATA_CLKCTRL/0x48180560 = 0x00070000
SATA_PLLCFG0/0x48140720 = 0xC0000000

in u-boot, remove the sata pll init code:
u-boot/board/ti/ti8148/evm.c -> sata_pll_config()

in linux kernel, remove sata pll and sata init code:
linux-kernel/arch/arm/mach-omap2/devices.c -> ti814x_sata_pllcfg() and omap_init_ahci()/ti81xx_ahci_plat_init()

BR
Pavel

Hi Pavel,

I see that CM_DEFAULT_SATA_CLKCTRL/0x48180560 = 0x00070000,
but SATA_PLLCFG0/0x48140720 = 0xC0000017

I tried commenting out the sata_pll_config() in uboot and saw that the U-boot itself
doesn’t come up. I see that sata serdes clock is used by GMII probably thats the reason it didnt boot up ?

Thanks And Regards
Mike

mike A said:

I tried commenting out the sata_pll_config() in uboot and saw that the U-boot itself
doesn’t come up. I see that sata serdes clock is used by GMII probably thats the reason it didnt boot up ?

That is correct.

Hi Pavel,

Is there a way to power down the SATA ?

Thanks And Regards,
Mike

Hi Pavel,

I tried commenting out the sata_pll_config() and with NO_ETH config enabled yet the board doesnt boot up any pointer on this ?

Thanks And Regards,
Mike

mike A said:

Is there a way to power down the SATA ?

No, SATA is in Always on power domain.

BR
Pavel

mike A said:

I tried commenting out the sata_pll_config() and with NO_ETH config enabled yet the board doesnt boot up any pointer on this ?

Try with removing ethernet support.

u-boot/board/ti/ti8148/em.c

void per_clocks_enable(void)
{

/* Ethernet */
    //__raw_writel(0x2, CM_ETHERNET_CLKSTCTRL);
    //__raw_writel(0x2, CM_ALWON_ETHERNET_0_CLKCTRL);
    //while((__raw_readl(CM_ALWON_ETHERNET_0_CLKCTRL) & 0x30000) != 0);
    //__raw_writel(0x2, CM_ALWON_ETHERNET_1_CLKCTRL);

u-boot/include/configs/ti8148_evm.h

//# define CONFIG_DRIVER_TI_CPSW

BR
Pavel

mike A said:

How to disable

mike A said:

NEON

NEON is part of the Cortex-A8 ARM core and is documented in the Cortex-A8 ARM Core TRM, available at the ARM site:

I would recommend you to check this TRM how (if possible) to disable only NEON part of the Cortex-A8 ARM core. You can also contact the ARM support team if any questions regarding the ARM TRM.

The below wiki pages might be also in help:

BR
Pavel

mike A said:

how do I disable the clocks for SGX

SGX is disabled by default in u-boot and linux kernel, you should have the below values:

SGXPLL_PWRCTRL/0x481C50B0 = 0x30

SGXPLL_CLKCTRL[23] IDLE/0x481C50B4 = 1

CM_SGX_CLKSTCTRL/0x48180900 = 0x1

CM_SGX_CLKCTRL/0x48180920 = 0x70000

PM_SGX_PWRSTCTRL/0x48180F00 = 0x30000

PM_SGX_PWRSTST/0x48180F10 = 0

SGX is enabled through linux kernel loadable modules (omaplfb.ko, pvrsrvkm.ko and bufferclass_ti.ko), so if you do not load these modules into the kernel, SGX stay disabled.

BR
Pavel

mike A said:

how do I disable

mike A said:

DSP

Unless you load DSP firmware, DSP stay disable in u-boot and linux kernel. See the below e2e thread for more info:

BR
Pavel