Messages in this thread | | | Subject | Re: [PATCH] PM / OPP: Refactor counting of added OPPs for v2 to avoid unsupported OPPs | From | Dave Gerlach <> | Date | Tue, 21 Aug 2018 22:17:08 -0500 |
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Hi, On 08/21/2018 10:10 PM, Dave Gerlach wrote: > Currently the _of_add_opp_table_v2 call loops through the OPP nodes in > the operating-points-v2 table in the device tree and calls > _opp_add_static_v2 for each to add them to the table. It counts each > iteration through this loop as an added OPP, however on platforms making > use of the opp-supported-hw property, _opp_add_static_v2 does not add > OPPs that are not seen as supported on the platform but still returns > success, as this is valid. Because of this the count variable will > contain the number of OPP nodes in the table in device tree but not > necessarily the ones that are supported and actually added. > > As this count value is what is checked to determine if there are any > valid OPPs, if a platform has an operating-points-v2 table with all OPP > nodes containing opp-supported-hw values that are not currently > supported then _of_add_opp_table_v2 will fail to abort as it should due > to an empty table. > > Additionally, since commit 3ba98324e81a ("PM / OPP: Get > performance state using genpd helper"), the same count variable is > compared against the number of OPPs containing performance states and > requires that either all or none have pstates set, however in the case > of any opp table that has any entries that do not get added by > _opp_add_static_v2 due to incompatible opp-supported-hw fields, these > numbers will not match and _of_add_opp_table_v2 will incorrectly fail. > > In order to ensure the count variable reflects the number of OPPs > actually in the table, increment it during the existing loop which walks > the opp table to check if pstate is set and then use that for the > aforementioned checks. > > Fixes: 3ba98324e81a ("PM / OPP: Get performance state using genpd helper") > Signed-off-by: Dave Gerlach <d-gerlach@ti.com> > ---
This is needed to fix cpufreq probe on TI am335x platforms. Seems that arch/arm/boot/dts/am33xx.dtsi is the only operating-points-v2 table with multiple opp-supported-hw entries which may not all be supported at once, and this caused the count differences that led me here.
Regards, Dave
> drivers/opp/of.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/drivers/opp/of.c b/drivers/opp/of.c > index 7af0ddec936b..f288f83a2e62 100644 > --- a/drivers/opp/of.c > +++ b/drivers/opp/of.c > @@ -399,8 +399,6 @@ static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np) > > /* We have opp-table node now, iterate over it and add OPPs */ > for_each_available_child_of_node(opp_np, np) { > - count++; > - > ret = _opp_add_static_v2(opp_table, dev, np); > if (ret) { > dev_err(dev, "%s: Failed to add OPP, %d\n", __func__, > @@ -411,15 +409,22 @@ static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np) > } > } > > + /* > + * Iterate over the list of OPPs that were actually added, as > + * OPPs not supported by the hardware will be ignored by > + * _opp_add_static_v2 above. > + */ > + list_for_each_entry(opp, &opp_table->opp_list, node) { > + count++; > + pstate_count += !!opp->pstate; > + } > + > /* There should be one of more OPP defined */ > if (WARN_ON(!count)) { > ret = -ENOENT; > goto put_opp_table; > } > > - list_for_each_entry(opp, &opp_table->opp_list, node) > - pstate_count += !!opp->pstate; > - > /* Either all or none of the nodes shall have performance state set */ > if (pstate_count && pstate_count != count) { > dev_err(dev, "Not all nodes have performance state set (%d: %d)\n", >
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