I think I got the QSB running at 1GHz, this is what I did, the change seemed quite simple in the end. I haven't created a patch as there are several different patched levels of u-boot out there. This is based upon a clean u-boot-2009.08 from L2.6.35_11.09.01_ER_source_bundle, with the supplied u-boot patches applied, and a patch I found in a web search "ENGR00137552 MX53: increase VDDGP as 1.2V for 1GHZ". I hope it's useful to someone.
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file mx53_loco.c that's in /ltib/rpm/BUILD/u-boot-2009.08/board/freescale:
In function board_init(void), I found there are already some commented out lines to do with setting PMIC voltage and switching to 1GHz. Uncomment these so you are left with:
#ifdef CONFIG_I2C_MXC
setup_i2c(CONFIG_SYS_I2C_PORT);
i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
/* delay pmic i2c access to board_late_init()
due to i2c_probe fail here on loco/ripley board. */
/* Increase VDDGP voltage */
setup_pmic_voltages();
/* Switch to 1GHZ */
clk_config(CONFIG_REF_CLK_FREQ, 1000, CPU_CLK);
#endif
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Also in the same file, locate the function void setup_pmic_voltages(void), which for my file was actually completely empty. Add in some lines as below:
void setup_pmic_voltages(void)
{
int value;
i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
/* increase VDDGP as 1.2V for 1GHZ */
value = 0x5c;
i2c_write(0x48, 0x2e, 1, &value, 1);
}
Then rebuild and deploy. For me this booted straightaway into 1GHz, boot text is:
U-Boot 2009.08 (May 26 2012 - 08:22:20)
CPU: Freescale i.MX53 family 2.1V at 1000 MHz
mx53 pll1: 1000MHz
mx53 pll2: 400MHz
mx53 pll3: 432MHz
mx53 pll4: 455MHz
ipg clock : 66666666Hz
ipg per clock : 33333333Hz
uart clock : 66666666Hz
cspi clock : 108000000Hz
ahb clock : 133333333Hz
axi_a clock : 400000000Hz
axi_b clock : 200000000Hz
emi_slow clock: 133333333Hz
ddr clock : 400000000Hz
esdhc1 clock : 80000000Hz
esdhc2 clock : 80000000Hz
esdhc3 clock : 80000000Hz
esdhc4 clock : 80000000Hz
nfc clock : 26666666Hz