Re: [PATCH 2/2] arm: mvebu: clearfog: Add defconfig for SPI booting

["Pali Rohár" <pali@kernel.org>]

On Tuesday 28 February 2023 10:48:24 Pali Rohár wrote:
> On Monday 27 February 2023 17:17:31 Tony Dinh wrote:
> > Hi Pali,
> > 
> > On Mon, Feb 27, 2023 at 4:42 PM Tony Dinh <mibodhi@gmail.com> wrote:
> > >
> > > Hi Pali,
> > >
> > > On Mon, Feb 27, 2023 at 3:41 PM Tony Dinh <mibodhi@gmail.com> wrote:
> > > >
> > > > Hi Pali,
> > > > It is not related to this patch series (I also tested without the
> > > > patch series to confirm). But it is strange that I can no longer get
> > > > the configuration to boot from SPI. The 1st device in the boot order
> > > > is alway BOOTROM. The spl_boot_list is printed out below.
> > > >
> > > > <BEGIN LOG>
> > > > High speed PHY - Ended Successfully
> > > > mv_ddr: 14.0.0
> > > > DDR4 Training Sequence - Switching XBAR Window to FastPath Window
> > > > mv_ddr: completed successfully
> > > > board_boot_order spl_boot_list[0] = 15
> > > > Trying to boot from BOOTROM
> > > > Returning to BootROM (return address 0xffff05c4)...
> > > > BootROM: Image checksum verification PASSED
> > > > <END LOG>
> > > >
> > > > The SPL SPI configs (board Thecus N2350) are:
> > > > # grep SPL .config| grep SPI
> > > >
> > > > CONFIG_MVEBU_SPL_BOOT_DEVICE_SPI=y
> > > > CONFIG_SPL_DM_SPI=y
> > > > CONFIG_SPL_SPI_FLASH_SUPPORT=y
> > > > CONFIG_SPL_SPI=y
> > > > CONFIG_SPL_DM_SPI_FLASH=y
> > > > CONFIG_SPL_SPI_FLASH_TINY=y
> > > > # CONFIG_SPL_SPI_FLASH_MTD is not set
> > > > CONFIG_SPL_SPI_LOAD=y
> > > >
> > > > Did I miss something new lately?
> > > >
> > > > Thanks,
> > > > Tony
> > > >
> > > > Trying to boot from BOOTROM
> > > > Returning to BootROM (return address 0xffff05c4)...
> > > > BootROM: Image checksum verification PASSED
> > >
> > > It turns out that the board strapping register itself is the problem.
> > > boot_device=0x9 was printed out in arch/arm/mach-mvebu/cpu.c. It
> > > surely does not match what we expected for A38x  (#define
> > > BOOT_FROM_SPI 0x32). Actually 0x9 is not defined in cpu.c at all. So
> > > it fell to the default case, which is BOOTROM.
> > >
> > > <BEGIN LOG>
> > > U-Boot SPL 2023.04-rc2-tld-1-00089-g3fe03f96fc-dirty (Feb 27 2023 -
> > > 16:24:01 -0800)
> > > High speed PHY - Version: 2.0
> > > Detected Device ID 6820
> > > board SerDes lanes topology details:
> > >  | Lane # | Speed |  Type       |
> > >  --------------------------------
> > >  |   0    |   0   | SGMII0 |
> > >  |   1    |   3   | SATA0 |
> > >  |   2    |   3   | SATA1 |
> > >  |   4    |   5   | USB3 HOST0 |
> > >  |   5    |   5   | USB3 HOST1 |
> > >  --------------------------------
> > > High speed PHY - Ended Successfully
> > > mv_ddr: 14.0.0
> > > DDR4 Training Sequence - Switching XBAR Window to FastPath Window
> > > mv_ddr: completed successfully
> > > BOOTROM_REG=0x97001000 boot_device=0x9

Wait...

Stop here. BOOTROM_REG is the value of BOOTROM_ERR_REG register which is
mvebu register 0x182d0.

Boot strapping pins are available in the SAR_REG register which is mvebu
register 0x18600 and SPL prints it under name SAR_REG.

So above boot_device=9 is not strapping pin configuration but something
parsed from BOOTROM_ERR_REG.

So above 0x9 signal some A385 bootrom error and SPL in case case of any
error (value different from zero) always use bootrom for loading proper
u-boot. As it thinks that bootrom loaded u-boot via uart. Seems that
this assumption is incorrect.

Unfortunately upper four bits which above code parses from mvebu
register 0x182d0 are marked as reserved in functional specification.

So it is needed to inspect bootrom binary when it sets these bits...

> > > spl_boot_device boot_device = 15
> > > board_boot_order spl_boot_list[0] = 15
> > > Trying to boot from BOOTROM
> > > Returning to BootROM (return address 0xffff05c4)...
> > > BootROM: Image checksum verification PASSED
> > > <END LOG>
> > >
> > > Is there a chance this value 0x9 means something that we have not come across?
> > 
> > Found the answer in the A38x Hardware Specs. I've never noticed this
> > before. This board has the Sample at Reset set to boot from NAND!
> > 
> > "Table 48: Boot Device Mode Options
> > 0x9
> > BootROM Enabled, Boot from NAND: 8 bits width, with page size of 512B,
> > 4 Address cycles support per page, using MPP multiplexing option of
> > NAND 8 bits
> > 0x32
> > BootROM Enabled, Boot from SPI: Controller #0, 24 address bits, NOR
> > Flash type, using MPP multiplexing option of SPI on MPP[25:22]"
> > 
> > So what we actually see here is the fall back to BootROM. And BootROM
> > still loads the image from SPI, ignoring that strapping. Am I confused
> > or correct? :)
> > 
> > Thanks,
> > Tony
> 
> I already wrote in some thread that in Hardware Specifications are
> documented all strapping pins options and u-boot has defined just few of
> them in header files. Beware that strapping pins are SoC specific and so
> you always need to look at the correct document.
> 
> About parallel-NAND vs SPI-NOR, could you send the whole bootlog on uart
> from bootrom to main u-boot and type of the SoC?