[U-Boot] [PATCH 1/4] mmc: meson-gx: Fix tx phase in the tuning process

[Anand Moon]

Hi Neil,

On Wed, 27 Nov 2019 at 18:30, Neil Armstrong <narmstrong at baylibre.com> wrote:
>
> Hi,
>
> On 26/11/2019 22:12, Anand Moon wrote:
> > odroid n2 eMMC module would failed to boot up,
> > because of TX phase clk failure, fix the typo in
> > TX phase macro to help tune correct clk freqency.
> >
> > Before these changes.
> >   clock is enabled (380953Hz)
> >   clock is enabled (25000000Hz)
> > after these changes
> >   clock is enabled (380953Hz)
> >   clock is enabled (25000000Hz)
> >   clock is enabled (52000000Hz)
> >   clock is enabled (52000000Hz)
> >   clock is enabled (52000000Hz)
> >
> > Signed-off-by: Anand Moon <linux.amoon at gmail.com>
> > ---
> > Tested on
> > new orange - eMMC AJNB4R 14.6 GiB MMC 5.1
> > old back   - eMMC CGND3R 58.2 GiB MMC 5.0
> > ---
> >  drivers/mmc/meson_gx_mmc.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/meson_gx_mmc.c b/drivers/mmc/meson_gx_mmc.c
> > index 031cc79ccb..87bea2888b 100644
> > --- a/drivers/mmc/meson_gx_mmc.c
> > +++ b/drivers/mmc/meson_gx_mmc.c
> > @@ -53,7 +53,7 @@ static void meson_mmc_config_clock(struct mmc *mmc)
> >       meson_mmc_clk |= CLK_CO_PHASE_180;
> >
> >       /* 180 phase tx clock */
> > -     meson_mmc_clk |= CLK_TX_PHASE_000;
> > +     meson_mmc_clk |= CLK_TX_PHASE_180;
> >
> >       /* clock settings */
> >       meson_mmc_clk |= clk_src;
> >
>
> I don't understand what this change helps, the linux driver sets the TX phase to 0,
> why 180 would help here ?
>
> Neil

I narrow down to this small changes, without this small change
it fails to detect the eMMC module. See the below log.

U-Boot 2020.01-rc3-00082-g4b19b89ca4-dirty (Nov 27 2019 - 18:56:37
+0530) odroid-n2

Model: Hardkernel ODROID-N2
SoC:   Amlogic Meson G12B (S922X) Revision 29:a (40:2)
DRAM:  3.8 GiB
mmc_bind: alias ret=-2, devnum=-1
mmc_bind: alias ret=-2, devnum=-1
MMC:   clock is enabled (380953Hz)
clock is enabled (380953Hz)
sd at ffe05000: 0, mmc at ffe07000: 1
In:    serial at 3000
Out:   serial at 3000
Err:   serial at 3000
Net:   gpio_request_tail: Node 'ethernet at ff3f0000', property
'snps,reset-gpio', failed to request GPIO index 0: -2

Warning: ethernet at ff3f0000 (eth0) using random MAC address - 26:1e:2a:2a:67:d6
eth0: ethernet at ff3f0000
Hit any key to stop autoboot:  0
clock is disabled (0Hz)
regulator_common_set_enable: dev='regulator-tflash_vdd', enable=1,
delay=0, has_gpio=1
regulator_common_set_enable: done
clock is enabled (380953Hz)
Card did not respond to voltage select!
gpio_request_tail: Node 'regulator-vcc_3v3', property 'gpio', failed
to request GPIO index 0: -2
Regulator 'regulator-vcc_3v3' optional enable GPIO - not found! Error: -2
gpio_request_tail: Node 'regulator-flash_1v8', property 'gpio', failed
to request GPIO index 0: -2
Regulator 'regulator-flash_1v8' optional enable GPIO - not found! Error: -2
clock is disabled (0Hz)
regulator_common_set_enable: dev='regulator-vcc_3v3', enable=1,
delay=0, has_gpio=0
clock is enabled (380953Hz)
clock is enabled (25000000Hz)
unable to select a mode
switch to partitions #0, OK
mmc1(part 0) is current device
** No partition table - mmc 1 **
MMC Device 2 not found
no mmc device at slot 2
starting USB...
Bus usb at ff500000: gpio_request_tail: Node 'regulator-vcc_5v', property
'gpio', failed to request GPIO index 0: -2
Regulator 'regulator-vcc_5v' optional enable GPIO - not found! Error: -2
regulator_common_set_enable: dev='regulator-usb_pwr_en', enable=1,
delay=0, has_gpio=1
regulator_common_set_enable: done
Register 3000140 NbrPorts 3
Starting the controller
USB XHCI 1.10
scanning bus usb at ff500000 for devices... 1 USB Device(s) found
       scanning usb for storage devices... 0 Storage Device(s) found

-Anand