linux-kernel - Re: [PATCH] mailbox: qcom-apcs-ipc: use PLATFORM_DEVID

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Date:   Fri, 11 Dec 2020 22:12:02 +0800
From:   Shawn Guo <shawn.guo@...aro.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Jassi Brar <jassisinghbrar@...il.com>,
        Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konradybcio@...il.com>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mailbox: qcom-apcs-ipc: use PLATFORM_DEVID_AUTO to
 register device

On Fri, Dec 11, 2020 at 12:16 PM Bjorn Andersson
<bjorn.andersson@...aro.org> wrote:
>
> On Mon 12 Oct 21:12 CDT 2020, Shawn Guo wrote:
>
> > On MSM8916, only one qcom-apcs-msm8916-clk device is needed, as there is
> > only one APCS clock.  However, on MSM8939 three APCS clocks need to be
> > registered for cluster0 (little cores), cluster1 (big cores) and CCI
> > (Cache Coherent Interconnect).  That said, we will need to register 3
> > qcom-apcs-msm8916-clk devices.  Let's use PLATFORM_DEVID_AUTO rather
> > than PLATFORM_DEVID_NONE for platform_device_register_data() call.
> > Otherwise, the second APCS clock registration will fail due to duplicate
> > device name.
> >
> > [    0.519657] sysfs: cannot create duplicate filename '/bus/platform/devices/qcom-apcs-msm8916-clk'
> > ...
> > [    0.661158] qcom_apcs_ipc b111000.mailbox: failed to register APCS clk
> >
>
> Spotted this as I was looking for another patch, hence the late reply.
> But it seems this was never reviewed or merged.
>
> What does the bigger picture look like? Do we have 3 APCS global, or
> it's a single memory region that provides the 3 clocks? How does the
> qcom-apcs-msm8916-clk with it's hard coded offset of 0x50 deal with
> this? (Is this a single qcom-apcs-msm8939-clk that registers 3 clocks
> instead? Making this patch unnecessary?)

We have 3 APCS global instances.  I haven't got time to send out other
related patches, but the DT for these 3 APCS global looks like below.

                apcs2: mailbox@...1000 {
                        compatible = "qcom,msm8916-apcs-kpss-global", "syscon";
                        reg = <0xb1d1000 0x1000>;
                        #mbox-cells = <1>;
                        clocks = <&a53pll_cci>, <&gcc GPLL0_VOTE>;
                        clock-names = "pll", "aux";
                        #clock-cells = <0>;
                        clock-output-names = "a53mux_cci";
                };

                apcs1: mailbox@...1000 {
                        compatible = "qcom,msm8916-apcs-kpss-global", "syscon";
                        reg = <0xb011000 0x1000>;
                        #mbox-cells = <1>;
                        clocks = <&a53pll_c1>, <&gcc GPLL0_VOTE>;
                        clock-names = "pll", "aux";
                        #clock-cells = <0>;
                        clock-output-names = "a53mux_c1";
                };

                apcs0: mailbox@...1000 {
                        compatible = "qcom,msm8916-apcs-kpss-global", "syscon";
                        reg = <0xb111000 0x1000>;
                        #mbox-cells = <1>;
                        clocks = <&a53pll_c0>, <&gcc GPLL0_VOTE>;
                        clock-names = "pll", "aux";
                        #clock-cells = <0>;
                        clock-output-names = "a53mux_c0";
                };

Shawn