> 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: 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 = 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) { 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 -- 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
