Re: [PATCH] arm64: dts: qcom: glymur: Add missing USB clock, power and bandwidth votes

[Abel Vesa]

On 26-08-12 10:35:22, Greg Ociepka wrote:
> The four USB3 controller nodes on Glymur (usb_0, usb_1, usb_2, usb_mp)
> are missing three property groups that Glymur's own usb_hs node at
> a200000 already carries, and that Hamoa (x1e80100) carries on all five
> of its USB controllers:
> 
>   - assigned-clocks / assigned-clock-rates
>   - required-opps
>   - interconnects / interconnect-names
> 
> Without required-opps the controllers place no performance state vote
> on their power domain. Measured on an Asus Zenbook A16 (UX3607OA) with
> a SuperSpeed device enumerated, CX aggregates to SVS while the
> controllers run their master clock at 200 MHz:
> 
>   $ grep -E "^cx " /sys/kernel/debug/pm_genpd/pm_genpd_summary
>   cx    on    128
> 
>   $ grep "usb30.*master_clk " /sys/kernel/debug/clk/clk_summary
>   gcc_usb30_sec_master_clk   ...  200000000
>   gcc_usb30_prim_master_clk  ...  200000000
>   gcc_usb30_mp_master_clk    ...  200000000
> 
> 128 is RPMH_REGULATOR_LEVEL_SVS; rpmhpd_opp_nom is 256. With this
> patch applied the same measurement reads 256 while a controller is
> active.
> 
> Without interconnects, dwc3_qcom_interconnect_init() silently does
> nothing: of_icc_get() returns NULL rather than an error pointer for a
> device without the property, so probe succeeds and icc_set_bw() on a
> NULL path is a no-op. No USB-DDR bandwidth is ever requested.
> 
> Without assigned-clock-rates nothing programs the master clock RCG,
> which keeps whatever the bootloader left behind. On this machine that
> happens to be the correct 200 MHz, but ftbl_gcc_usb30_mp_master_clk_src
> also allows 66.67 and 133.33 MHz, neither of which sustains SuperSpeed.
> 
> Add all three groups to the four nodes, mirroring usb_hs. The
> interconnect paths follow the provider layout in
> drivers/interconnect/qcom/glymur.c: usb_0/usb_1 sit on aggre4_noc,
> usb_mp on aggre3_noc and usb_2 on aggre2_noc.
> 
> Fixes: 4eee57dd4df9 ("arm64: dts: qcom: glymur: Add USB related nodes")
> Assisted-by: Claude:fable-5
> Signed-off-by: Greg Ociepka <greg@xxxxxxxxxxxxx>

This looks OK to me.

Reviewed-by: Abel Vesa <abel.vesa@xxxxxxxxxxxxxxxx>

> ---
> Note for reviewers: Hamoa additionally marks all five USB controllers
> dma-coherent, while Glymur marks no peripheral DMA master as coherent
> (only the SMMUs, PCIe controllers and remoteprocs). That difference is
> deliberately not touched here since getting it wrong is a silent
> data-corruption class of bug, but it looks like part of the same
> omission. Is USB DMA coherent on Glymur?

I think so, but lets see what Wesley thinks.

+ Wesley