Re: [PATCH] ARM: dts: socfpga: remove syscon compatible string for sysmgr node

[Dinh Nguyen]

On 2/11/25 07:48, Rabara, Niravkumar L wrote:
> Hi Dinh,
>
> > -----Original Message-----
> > From: Dinh Nguyen <dinguyen@xxxxxxxxxx>
> > Sent: Tuesday, 11 February, 2025 8:57 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 06:37, Rabara, Niravkumar L wrote:
> > > 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, &reg_offset);
> > > > > 	of_property_read_u32_index(np, "altr,sysmgr-syscon", 2, &reg_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
> >
> > Can you try an image that removes MFD_SYSCON from the
> > MFD_ALTERA_SYSMGR?
>
> Tried image without MFD_SYSCON in MFD_ALTERA_SYSMGR - Kconfig,
> it still works without any error/warning.

Then something has changed and I'd like for you to investigate what 
changed. This whole driver is using syscon, and now it appears that it's 
not? It doesn't make sense to me. Please investigate more.

Dinh