[PATCH] arm: mvebu: spl: Always fallback to BootROM boot method

[Pali Rohár]

Hello! We have tested that A385 BootROM on Turris Omnia board is much
slower when reading proper U-Boot from SPI NOR than native SPL SPI
driver.

If you have different test results on A385, could you check SPI speed
used by U-Boot? I think that CONFIG_SF_DEFAULT_SPEED should define it.
For Omnia we use CONFIG_SF_DEFAULT_SPEED=40000000. Also check value of
DT property spi-max-frequency. We have: spi-max-frequency = <40000000>;

On Tuesday 02 August 2022 14:50:32 Tony Dinh wrote:
> Hi Pali,
> 
> It works great!
> 
> An observation: BootROM boot method is a lot faster than SPL SPI
> driver method on this Armada 385 board. The BootROM took a fraction of
> a second to load the u-boot image. SPL SPI driver took a few seconds
> to load. Perhaps the SPI flash speed vs some probing code in SPL SPI
> driver? I also include the boot log after signature.
> 
> Tested-by: Tony Dinh <mibodhi at gmail.com>
> 
> Thanks,
> Tony
> 
> <Begin boot log>
> 
> BootROM - 1.73
> Booting from SPI flash
> 
> U-Boot SPL 2022.10-rc1-00212-g80e1491a03-dirty (Aug 02 2022 - 14:07:12 -0700)
> High speed PHY - Version: 2.0
> Detected Device ID 6820
> board SerDes lanes topology details:
>  | Lane # | Speed |  Type       |
>  --------------------------------
>  |   0    |   0   | SGMII0 |
>  |   1    |   6   | SATA0 |
>  |   4    |   5   | USB3 HOST0 |
>  |   5    |   5   | USB3 HOST1 |
>  --------------------------------
> High speed PHY - Ended Successfully
> mv_ddr: 14.0.0
> DDR3 Training Sequence - Switching XBAR Window to FastPath Window
> mv_ddr: completed successfully
> Trying to boot from SPI
> Invalid bus 0 (err=-19)
> SPI probe failed.
> Trying to boot from BOOTROM
> Returning to BootROM (return address 0xffff05c4)...
> BootROM: Image checksum verification PASSED
> 
> 
> U-Boot 2022.10-rc1-00212-g80e1491a03-dirty (Aug 02 2022 - 14:07:12 -0700)
> Synology DS116
> 
> SoC:   MV88F6820-A0 at 1866 MHz
> DRAM:  1 GiB (933 MHz, 32-bit, ECC not enabled)
> Core:  41 devices, 18 uclasses, devicetree: separate
> MMC:
> Loading Environment from SPIFlash... SF: Detected mx25l6405d with page
> size 256 Bytes, erase size 4 KiB, total 8 MiB
> OK
> Model: Synology DS116
> Board: Synology DS116
> Net:   eth0: ethernet at 70000
> Hit any key to stop autoboot:  0
> 
> <End boot log>
> 
> 
> On Tue, Aug 2, 2022 at 2:55 AM Pali Rohár <pali at kernel.org> wrote:
> >
> > BootROM boot method should always work so always add it as fallback method
> > to spl_boot_list. In case U-Boot SPI driver fails it is better to try using
> > BootROM than hanging as by default only one boot method is specified.
> >
> > Signed-off-by: Pali Rohár <pali at kernel.org>
> > ---
> >  arch/arm/mach-mvebu/spl.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/arch/arm/mach-mvebu/spl.c b/arch/arm/mach-mvebu/spl.c
> > index 13c99913c380..bfcba2e73bab 100644
> > --- a/arch/arm/mach-mvebu/spl.c
> > +++ b/arch/arm/mach-mvebu/spl.c
> > @@ -271,6 +271,13 @@ u32 spl_boot_device(void)
> >         }
> >  }
> >
> > +void board_boot_order(u32 *spl_boot_list)
> > +{
> > +       spl_boot_list[0] = spl_boot_device();
> > +       if (spl_boot_list[0] != BOOT_DEVICE_BOOTROM)
> > +               spl_boot_list[1] = BOOT_DEVICE_BOOTROM;
> > +}
> > +
> >  #else
> >
> >  u32 spl_boot_device(void)
> > --
> > 2.20.1
> >