On Thu, Jan 12, 2023 at 04:41:50PM +0100, Konrad Dybcio wrote:
>
>
> On 12.01.2023 16:37, Bjorn Andersson wrote:
> > On Wed, Jan 11, 2023 at 09:51:25PM +0100, Konrad Dybcio wrote:
> >> In preparation for CPRh-aware OSM programming, change the probe
> >> function so that we determine the number of frequency domains by
> >> counting the number of reg-names entries that begin with
> >> "freq-domain", as the aforementioned changes require introduction
> >> of non-freq-domain register spaces.
> >>
> >
> > Requiring reg-names would break backwards compatibility with at least
> > sc7280 and sm6115.
> Ouch, you're correct..
>
> Does checking for reg-names and applying the code flow proposed in this
> patch if found and the existing one if not sound good?
Why support 2 ways?
> Konrad
> >
> > Regards,
> > Bjorn
> >
> >> Fixes: 1a6a8b0080b0 ("cpufreq: qcom-hw: Fix reading "reg" with address/size-cells != 2")
> >> Fixes: 054a3ef683a1 ("cpufreq: qcom-hw: Allocate qcom_cpufreq_data during probe")
> >> Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
> >> ---
> >> drivers/cpufreq/qcom-cpufreq-hw.c | 34 ++++++++++++++++++++++---------
> >> 1 file changed, 24 insertions(+), 10 deletions(-)
> >>
> >> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
> >> index 9505a812d6a1..89d5ed267399 100644
> >> --- a/drivers/cpufreq/qcom-cpufreq-hw.c
> >> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c
> >> @@ -651,8 +651,9 @@ static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev)
> >> struct device *dev = &pdev->dev;
> >> struct device_node *soc_node;
> >> struct device *cpu_dev;
> >> + const char *reg_name;
> >> struct clk *clk;
> >> - int ret, i, num_domains, reg_sz;
> >> + int ret, i, num_reg_names, num_domains = 0;
> >>
> >> clk = clk_get(dev, "xo");
> >> if (IS_ERR(clk))
> >> @@ -684,19 +685,32 @@ static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev)
> >> if (!soc_node)
> >> return -EINVAL;
> >>
> >> - ret = of_property_read_u32(soc_node, "#address-cells", ®_sz);
> >> - if (ret)
> >> + num_reg_names = of_property_count_strings(dev->of_node, "reg-names");
> >> + if (num_reg_names <= 0) {
> >> + ret = num_reg_names ? num_reg_names : -ENODATA;
> >> goto of_exit;
> >> + }
> >>
> >> - ret = of_property_read_u32(soc_node, "#size-cells", &i);
> >> - if (ret)
> >> - goto of_exit;
> >> + for (i = 0; i < num_reg_names; i++) {
> >> + ret = of_property_read_string_index(dev->of_node, "reg-names", i, ®_name);
> >> + if (ret < 0)
> >> + goto of_exit;
> >>
> >> - reg_sz += i;
> >> + /*
> >> + * Check if the i-th reg is a freq-domain base, no need to add 1
> >> + * more byte for idx, as sizeof counts \0 whereas strlen does not.
> >> + */
> >> + if (strlen(reg_name) == sizeof("freq-domain")) {
> >> + /* Check if this reg-name begins with "freq-domain" */
> >> + if (!strncmp(reg_name, "freq-domain", sizeof("freq-domain") - 1))
> >> + num_domains++;
> >> + }
> >> + }
> >>
> >> - num_domains = of_property_count_elems_of_size(dev->of_node, "reg", sizeof(u32) * reg_sz);
This code was not great to begin with. Any code parsing 'reg' on it's
own is suspect IMO. It's a standard property and all parsing of it
should be in drivers/of/address.c. (Yes, I know there are other cases.)
The reg entries are already available as platform_device resources? Why
don't you use that? There's also of_address_count(), but I prefer if
there's a platform device equivalent like we have for interrupts.
Rob
