On Tue, Jun 7, 2011 at 20:41, Menon, Nishanth <nm@xxxxxx> wrote: > On Tue, Jun 7, 2011 at 20:12, Colin Cross <ccross@xxxxxxxxxx> wrote: >>> Bootloaders should in theory setup a frequency which is enabled in >>> OPP table. However, there can be mismatches, and we should try >>> both going lower in addition to the going higher to find >>> a match if bootloader boots up at a OPP than the kernel thinks it >>> should be allowed. We also sequence the frequency and voltage settings >>> properly. >>> >>> Reported-by: Colin Cross <ccross@xxxxxxxxxx> >>> Signed-off-by: Nishanth Menon <nm@xxxxxx> >>> --- >>> PS: Apologies on the spam.. for some reason 10/10 never appeared in >>> http://marc.info/?l=linux-omap&r=2&b=201106&w=2 - grumble grumble :( >>> >>> arch/arm/mach-omap2/pm.c | 55 ++++++++++++++++++++++++++++++++++++--------- >>> 1 files changed, 44 insertions(+), 11 deletions(-) >>> >>> diff --git a/arch/arm/mach-omap2/pm.c b/arch/arm/mach-omap2/pm.c >>> index 7355347..ce7554b 100644 >>> --- a/arch/arm/mach-omap2/pm.c >>> +++ b/arch/arm/mach-omap2/pm.c >>> @@ -174,7 +174,9 @@ static int __init omap2_set_init_voltage(char *vdd_name, ch ar *clk_name, >>> struct voltagedomain *voltdm; >>> struct clk *clk; >>> struct opp *opp; >>> - unsigned long freq, bootup_volt; >>> + unsigned long freq_cur, freq_valid, bootup_volt; >>> + int raise_freq_idx, i; >>> + int ret = -EINVAL; >>> >>> if (!vdd_name || !clk_name || !dev) { >>> printk(KERN_ERR "%s: Invalid parameters!\n", __func__); >>> @@ -195,16 +197,20 @@ static int __init omap2_set_init_voltage(char *vdd_name, char *clk_name, >>> goto exit; >>> } >>> >>> - freq = clk->rate; >>> - clk_put(clk); >>> + freq_cur = clk->rate; >>> + freq_valid = freq_cur; >>> >>> rcu_read_lock(); >>> - opp = opp_find_freq_ceil(dev, &freq); >>> + opp = opp_find_freq_ceil(dev, &freq_valid); >>> if (IS_ERR(opp)) { >>> - rcu_read_unlock(); >>> - printk(KERN_ERR "%s: unable to find boot up OPP for vdd_%s\n", >>> - __func__, vdd_name); >>> - goto exit; >>> + opp = opp_find_freq_floor(dev, &freq_valid); >>> + if (IS_ERR(opp)) { >>> + rcu_read_unlock(); >>> + pr_err("%s: no boot OPP match for %ld on vdd_%s\n", >>> + __func__, freq_cur, vdd_name); >>> + ret = -ENOENT; >>> + goto exit_ck; >>> + } >>> } >>> >>> bootup_volt = opp_get_voltage(opp); >>> @@ -212,11 +218,38 @@ static int __init omap2_set_init_voltage(char *vdd_name, char *clk_name, >>> if (!bootup_volt) { >>> printk(KERN_ERR "%s: unable to find voltage corresponding" >>> "to the bootup OPP for vdd_%s\n", __func__, vdd_name); >>> - goto exit; >>> + ret = -ENOENT; >>> + goto exit_ck; >>> } >>> >>> - voltdm_scale(voltdm, bootup_volt); >>> - return 0; >>> + /* >>> + * Frequency and Voltage have to be sequenced: if we move from >>> + * a lower frequency to higher frequency, raise voltage, followed by >>> + * frequency, and vice versa. we assume that the voltage at boot >>> + * is the required voltage for the frequency it was set for. >>> + */ >>> + raise_freq_idx = freq_cur < freq_valid; >>> + for (i = 0; i < 2; i++) { >>> + if (i == raise_freq_idx) >>> + ret = clk_set_rate(clk, freq_valid); >>> + else >>> + ret = voltdm_scale(voltdm, bootup_volt); >>> + if (ret < 0) { >>> + pr_err("%s: unable to set %s-%s(f=%ld v=%ld)on vdd%s\n", >>> + __func__, >>> + (i == raise_freq_idx) ? "clk" : "voltage", >>> + (i == raise_freq_idx) ? clk_name : vdd_name, >>> + freq_valid, bootup_volt, vdd_name); >>> + goto exit_ck; >>> + } >>> + } >> >> This is way too complicated. Writing out what you mean is much more >> readable, and not many more LOC: > hmm.. fine with me.. > >> >> if (freq_cur < freq_valid) { >> ret = voltdm_scale(voltdm, bootup_volt); >> if (ret) { >> pr_err("%s: unable to set voltage-%s(f=%ld v=%ld)on vdd%s\n", >> vdd_name, freq_valid, bootup_volt, vdd_name); >> goto exit_ck; >> } >> } >> > optionally - > if (freq_cur == freq_valid) { oops.. typo - intended: if (freq_cur != freq_valid) { Since the get_rate already says that we are in proper freq, why do set_rate again? > > ret = clk_set_rate(clk, freq_valid); > > if (ret) { > > pr_err("%s: unable to set clk-%s(f=%ld v=%ld)on vdd%s\n", > > clk_name, freq_valid, bootup_volt, vdd_name); > > goto exit_ck; > > } > } >> >> if (freq_cur > freq_valid) { > since we dont really know how the bootloader might have set the > voltage, (twl4030 allows i2c1 programming, others plugged on I2C_SR > can either use forcedupdate/vc bypass, we should do a force setting of > voltage.. > if (freq_cur >= freq_valid) ? > >> ret = voltdm_scale(voltdm, bootup_volt); >> if (ret) { >> pr_err("%s: unable to set voltage-%s(f=%ld v=%ld)on vdd%s\n", >> vdd_name, freq_valid, bootup_volt, vdd_name); >> goto exit_ck; >> } >> } >> >>> + >>> + ret = 0; >>> +exit_ck: >>> + clk_put(clk); >>> + >>> + if (!ret) >>> + return 0; >>> >>> exit: >>> printk(KERN_ERR "%s: Unable to put vdd_%s to its init voltage\n\n", >>> -- >>> 1.7.1 >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-omap" in >>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > > Regards, > Nishanth Menon > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
