[U-Boot] [PATCH v2 5/8] spi: cadence_qspi: add reset handling

[Marek Vasut]

On 2/22/19 7:06 AM, Simon Goldschmidt wrote:
> On Thu, Feb 21, 2019 at 11:14 PM Marek Vasut <marex at denx.de> wrote:
>>
>> On 2/21/19 11:04 PM, Simon Goldschmidt wrote:
>>>
>>>
>>> Am Do., 21. Feb. 2019, 22:56 hat Marek Vasut <marex at denx.de
>>> <mailto:marex at denx.de>> geschrieben:
>>>
>>>     On 2/21/19 10:43 PM, Simon Goldschmidt wrote:
>>>     > This adds reset handling to the cadence qspi driver.
>>>     >
>>>     > For backwards compatibility, only a warning is printed when failing to
>>>     > get reset handles.
>>>     >
>>>     > Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com
>>>     <mailto:simon.k.r.goldschmidt at gmail.com>>
>>>     > ---
>>>     >
>>>     > Changes in v2:
>>>     > - add .remove callback to release the resets
>>>     >
>>>     >  drivers/spi/cadence_qspi.c | 16 ++++++++++++++++
>>>     >  drivers/spi/cadence_qspi.h |  4 ++++
>>>     >  2 files changed, 20 insertions(+)
>>>     >
>>>     > diff --git a/drivers/spi/cadence_qspi.c b/drivers/spi/cadence_qspi.c
>>>     > index 11fce9c4fe..3bfa0201c4 100644
>>>     > --- a/drivers/spi/cadence_qspi.c
>>>     > +++ b/drivers/spi/cadence_qspi.c
>>>     > @@ -8,6 +8,7 @@
>>>     >  #include <dm.h>
>>>     >  #include <fdtdec.h>
>>>     >  #include <malloc.h>
>>>     > +#include <reset.h>
>>>     >  #include <spi.h>
>>>     >  #include <linux/errno.h>
>>>     >  #include "cadence_qspi.h"
>>>     > @@ -154,10 +155,17 @@ static int cadence_spi_probe(struct udevice
>>>     *bus)
>>>     >  {
>>>     >       struct cadence_spi_platdata *plat = bus->platdata;
>>>     >       struct cadence_spi_priv *priv = dev_get_priv(bus);
>>>     > +     int ret;
>>>     >
>>>     >       priv->regbase = plat->regbase;
>>>     >       priv->ahbbase = plat->ahbbase;
>>>     >
>>>     > +     ret = reset_get_bulk(bus, &priv->resets);
>>>     > +     if (ret)
>>>     > +             dev_warn(bus, "Can't get reset: %d\n", ret);
>>>     > +     else
>>>     > +             reset_deassert_bulk(&priv->resets);
>>>     > +
>>>     >       if (!priv->qspi_is_init) {
>>>     >               cadence_qspi_apb_controller_init(plat);
>>>     >               priv->qspi_is_init = 1;
>>>     > @@ -166,6 +174,13 @@ static int cadence_spi_probe(struct udevice *bus)
>>>     >       return 0;
>>>     >  }
>>>     >
>>>     > +static int cadence_spi_remove(struct udevice *dev)
>>>     > +{
>>>     > +     struct cadence_spi_priv *priv = dev_get_priv(dev);
>>>     > +
>>>     > +     return reset_release_bulk(&priv->resets);
>>>     > +}
>>>     > +
>>>     >  static int cadence_spi_set_mode(struct udevice *bus, uint mode)
>>>     >  {
>>>     >       struct cadence_spi_priv *priv = dev_get_priv(bus);
>>>     > @@ -342,4 +357,5 @@ U_BOOT_DRIVER(cadence_spi) = {
>>>     >       .platdata_auto_alloc_size = sizeof(struct cadence_spi_platdata),
>>>     >       .priv_auto_alloc_size = sizeof(struct cadence_spi_priv),
>>>     >       .probe = cadence_spi_probe,
>>>     > +     .remove = cadence_spi_remove,
>>>
>>>     .remove() only ever gets executed for drivers setting DM_FLAG_OS_PREPARE
>>>     flag. Fix this in the other drivers too.
>>>
>>>
>>> Ehrm, I haven't checked, but is this common practice? Why doesn't it
>>> always get called?
>>
>> That's how the code behaves. Probably to speed up booting the kernel on
>> devices which don't need to be torn down.
> 
> What surprises me is that the OS_PREPARE flag is used only for one spi driver
> and for 'mmc_blk' (but this is really new). Is it still the right
> thing to do? How could
> this be one of the first drivers releasing its reset before boot? :-)

I suspect this might be an area for improvement :)

-- 
Best regards,
Marek Vasut