Hi Dinh,
> -----Original Message-----
> From: Dinh Nguyen <dinguyen@xxxxxxxxxx>
> Sent: Tuesday, 11 February, 2025 8:25 PM
> To: Rabara, Niravkumar L <niravkumar.l.rabara@xxxxxxxxx>; Rob Herring
> <robh@xxxxxxxxxx>; Krzysztof Kozlowski <krzk+dt@xxxxxxxxxx>; Conor Dooley
> <conor+dt@xxxxxxxxxx>; devicetree@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Cc: lkp <lkp@xxxxxxxxx>
> Subject: Re: [PATCH] ARM: dts: socfpga: remove syscon compatible string for
> sysmgr node
>
> On 2/11/25 06:18, Rabara, Niravkumar L wrote:
> > Hi Dinh,
> >
> >> -----Original Message-----
> >> From: Dinh Nguyen <dinguyen@xxxxxxxxxx>
> >> Sent: Tuesday, 11 February, 2025 12:15 PM
> >> To: Rabara, Niravkumar L <niravkumar.l.rabara@xxxxxxxxx>; Rob Herring
> >> <robh@xxxxxxxxxx>; Krzysztof Kozlowski <krzk+dt@xxxxxxxxxx>; Conor
> >> Dooley <conor+dt@xxxxxxxxxx>; devicetree@xxxxxxxxxxxxxxx; linux-
> >> kernel@xxxxxxxxxxxxxxx
> >> Cc: lkp <lkp@xxxxxxxxx>
> >> Subject: Re: [PATCH] ARM: dts: socfpga: remove syscon compatible
> >> string for sysmgr node
> >>
> >>> Yes, I have tested this using NFS boot, however I didn't observe any
> >>> issue with SD/MMC driver.
> >>>
> >>> => fdt print /soc/mmc@ff808000
> >>> mmc@ff808000 {
> >>> #address-cells = <0x00000001>;
> >>> #size-cells = <0x00000000>;
> >>> compatible = "altr,socfpga-dw-mshc";
> >>> reg = <0xff808000 0x00001000>;
> >>> interrupts = <0x00000000 0x00000062 0x00000004>;
> >>> fifo-depth = <0x00000400>;
> >>> clocks = <0x0000001a 0x00000024>;
> >>> clock-names = "biu", "ciu";
> >>> resets = <0x00000006 0x00000027>;
> >>> altr,sysmgr-syscon = <0x0000001c 0x00000028 0x00000004>;
> >>> status = "okay";
> >>> cap-sd-highspeed;
> >>> cap-mmc-highspeed;
> >>> broken-cd;
> >>> bus-width = <0x00000004>;
> >>> clk-phase-sd-hs = <0x00000000 0x00000087>;
> >>> phandle = <0x00000029>;
> >>> };
> >>> => fdt print /soc/sysmgr@ffd06000
> >>> sysmgr@ffd06000 {
> >>> compatible = "altr,sys-mgr";
> >>> reg = <0xffd06000 0x00000300>;
> >>> cpu1-start-addr = <0xffd06230>;
> >>> phandle = <0x0000001c>;
> >>> };
> >>>
> >>> [ 1.095784] mmc_host mmc0: Bus speed (slot 0) = 50000000Hz (slot req
> >> 50000000Hz, actual 50000000HZ div = 0)
> >>> [ 1.105692] mmc0: new high speed SDHC card at address 0001
> >>> [ 1.108238] at24 0-0051: supply vcc not found, using dummy regulator
> >>> [ 1.111817] mmcblk0: mmc0:0001 SD32G 29.1 GiB
> >>> [ 1.118872] at24 0-0051: 4096 byte 24c32 EEPROM, writable, 32
> >> bytes/write
> >>> [ 1.129186] mmcblk0: p1 p2 p3
> >>>
> >>> .
> >>>
> >>> root@arria10:~# ls /dev/mmcblk0*
> >>> /dev/mmcblk0 /dev/mmcblk0p1 /dev/mmcblk0p2 /dev/mmcblk0p3
> >>> root@arria10:~# mount /dev/mmcblk0p1 /tmp/ root@arria10:~# ls /tmp/
> >>> extlinux socfpga_arria10_socdk_sdmmc.dtb zImage
> >>> fit_spl_fpga.itb u-boot.img
> >>>
> >>>
> >>
> >> You didn't really test anything. There's a register in the System
> >> Manager that has set the SD/MMC clk-phase in U-Boot. So you won't see
> >> the failure unless you explicitly change the value in that register
> >> and then boot Linux, then you will see the failure. If you look at
> >> drivers/mmc/host/dw_mmc-pltfm.c and look at the function
> >> dw_mci_socfpga_priv_init(), you can see that work in action. If you remove
> the syscon property, then that portion of the driver will fail.
> >> Also the ethernet driver is using the system manager's to set the
> >> correct PHY mode through syscon. I think you need to test this patch more
> thoroughly.
> >>
> >> DInh
> >
> > Altera System Manager driver (drivers/mfd/altera-sysmgr.c) is enabled
> > in "socfpga_defconfig" - i.e. CONFIG_MFD_ALTERA_SYSMGR=y
> >
> > So, SoCFPGA always using drivers/mfd/altera-sysmgr.c for System
> > Manager register access, not the generic "syscon" drivers/mfd/syscon.c.
> > That's why we do not need "syscon" compatible for fall back mechanism.
> >
> > sysmgr: sysmgr@ffd08000 {
> > - compatible = "altr,sys-mgr", "syscon";
> > + compatible = "altr,sys-mgr";
> > reg = <0xffd08000 0x4000>;
> > };
> > mmc: mmc@ff808000 {
> > …
> > altr,sysmgr-syscon = <&sysmgr 0x28 4>;
> > clk-phase-sd-hs = <0>, <135>;
> > …
> > };
> > gmac0: ethernet@ff800000 {
> > …
> > altr,sysmgr-syscon = <&sysmgr 0x44 0>;
> > …
> > };
> >
> >
> > Even the sdmmc driver you mentioned is using "drivers/mfd/altera-sysmgr.c"
> > not the generic "syscon" drivers/mfd/syscon.c. Same thing for ethernet
> > driver as well.
> >
> > dw_mci_socfpga_priv_init() {
> > ...
> > rc = of_property_read_variable_u32_array(np, "clk-phase-sd-hs",
> &clk_phase[0], 2, 0);
> > if (rc < 0)
> > return 0;
> >
> > sys_mgr_base_addr = altr_sysmgr_regmap_lookup_by_phandle(np,
> "altr,sysmgr-syscon");
> > if (IS_ERR(sys_mgr_base_addr)) {
> > dev_warn(host->dev, "clk-phase-sd-hs was specified, but failed
> to find altr,sys-mgr regmap!\n");
> > return 0;
> > }
> >
> > of_property_read_u32_index(np, "altr,sysmgr-syscon", 1, ®_offset);
> > of_property_read_u32_index(np, "altr,sysmgr-syscon", 2, ®_shift);
> > ...
> > }
> >
> > Please let me know if my understanding is incorrect.
> >
>
> But the altera-sysmgr driver is using syscon as the interface:
>
> config MFD_ALTERA_SYSMGR
> bool "Altera SOCFPGA System Manager"
> depends on ARCH_INTEL_SOCFPGA && OF
> select MFD_SYSCON
>
> Can you look at your bootlog and see if you see this message ""clk-phase-sd-hs
> was specified, but failed to find altr,sys-mgr regmap!"?
>
No, I do not see this error/warning in boot log.
" clk-phase-sd-hs was specified, but failed to find altr,sys-mgr regmap!"
Also I did test by manually changing the clock phase register value in u-boot,
and then boot Linux without "syscon" compatible, and I do not see any error or
warning and sdmmc and ethernet drivers are working fine.
=> md.l 0xffd06028 1
ffd06028: 00000003 ....
=> mw.l 0xffd06028 0x0
Thanks,
Nirav
