Hi, Geert,
On 04.08.2025 13:00, Geert Uytterhoeven wrote:
> Hi Claudiu,
>
> On Fri, 4 Jul 2025 at 15:43, Claudiu <claudiu.beznea@xxxxxxxxx> wrote:
>> From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
>>
>> Add MSTOP configuration for all the module clocks on the RZ/G2L
>> based SoCs (RZ/G2L, RZ/G2LC).
>>
>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
>
> Thanks for your patch!
>
>> --- a/drivers/clk/renesas/r9a07g044-cpg.c
>> +++ b/drivers/clk/renesas/r9a07g044-cpg.c
>> @@ -242,163 +242,163 @@ static const struct {
>> } mod_clks = {
>> .common = {
>
>> DEF_MOD("gpu_clk", R9A07G044_GPU_CLK, R9A07G044_CLK_G,
>> - 0x558, 0, 0),
>> + 0x558, 0, MSTOP(BUS_REG1, BIT(4))),
>> DEF_MOD("gpu_axi_clk", R9A07G044_GPU_AXI_CLK, R9A07G044_CLK_P1,
>> 0x558, 1, 0),
>> DEF_MOD("gpu_ace_clk", R9A07G044_GPU_ACE_CLK, R9A07G044_CLK_P1,
>> 0x558, 2, 0),
>
> Perhaps these two should have "MSTOP(BUS_REG1, BIT(4))", too?
According to table "Table 42.3 Registers for Module Standby Mode" only bit
0 of CPG_CLKON_3DGE maps to bit 4 of CPG_BUS_REG1_MSTOP. There are no hints
in the description of CPG_BUS_REG1_MSTOP neither in the description of
CPG_CLKON_3DGE registers that leads to having bit 4 of CPG_BUS_REG1_MSTOP
for AXI or ACE clocks as well.
I tried to play with MSTOP and clocks at runtime to see if there is any
relation b/w them but can't establish something.
I tried the following steps:
a/ remove the panfrost module (at this point all clocks are disabled and
mstop != 0)
b/ devmem2 0x11010858 w 0x130013 # de-assert the GPU resets
c/ devmem2 0x11010b80 w 0x100000 # switch the module to normal
d/ enable different clocks and read one register as follows:
1/ gpu_axi enabled -> devmem 0x11840000 fail
2/ gpu_axi, gpu_ace enabled -> devmem 0x11840000 fail
3/ gpu_axi, gpu_ace, gpu_clk enabled -> devmem 0x11840000 OK
4/ gpu_clk enabled -> devmem2 0x11840000 fail
5/ gpu_clk, gpu_axi enabled -> devmem2 0x11840000 OK
6/ gpu_clk, gpu_ace enabled -> devmem2 0x11840000 fail
7/ gpu_ace enabled -> devmem2 0x11840000 fail
8/ gpu_ace, gpu_clk enabled -> devmem2 0x11840000 fail
