Re: [PATCH v6 07/23] drivers/fsi: Implement slave initialisation

[Christopher Bostic]

On 5/2/17 1:24 AM, Joel Stanley wrote:
> On Tue, Apr 11, 2017 at 5:16 AM, Christopher Bostic
> <cbostic@xxxxxxxxxxxxxxxxxx> wrote:
> > From: Jeremy Kerr <jk@xxxxxxxxxx>
> >
> > Implement fsi_slave_init: if we can read a chip ID, create fsi_slave
> > devices and register with the driver core.
> >
> > Includes changes from Chris Bostic <cbostic@xxxxxxxxxxxxxxxxxx>.
> >
> > Signed-off-by: Jeremy Kerr <jk@xxxxxxxxxx>
> > Signed-off-by: Chris Bostic <cbostic@xxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
> > ---
> >   drivers/fsi/fsi-core.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++--
> >   1 file changed, 64 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
> > index 6e1cfdf..c705ca2 100644
> > --- a/drivers/fsi/fsi-core.c
> > +++ b/drivers/fsi/fsi-core.c
> > @@ -17,9 +17,12 @@
> >   #include <linux/fsi.h>
> >   #include <linux/idr.h>
> >   #include <linux/module.h>
> > +#include <linux/slab.h>
> >
> >   #include "fsi-master.h"
> >
> > +#define FSI_SLAVE_SIZE_23b             0x800000
> > +
> >   static DEFINE_IDA(master_ida);
> >
> >   struct fsi_slave {
> > @@ -114,11 +117,70 @@ static int fsi_slave_write(struct fsi_slave *slave, uint32_t addr,
> >                          addr, val, size);
> >   }
> >
> > +static void fsi_slave_release(struct device *dev)
> > +{
> > +       struct fsi_slave *slave = to_fsi_slave(dev);
> > +
> > +       kfree(slave);
> > +}
> > +
> >   static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
> >   {
> > -       /* todo: initialise slave device, perform engine scan */
> > +       struct fsi_slave *slave;
> > +       uint32_t chip_id;
> > +       uint8_t crc;
> > +       int rc;
> > +
> > +       /* Currently, we only support single slaves on a link, and use the
> > +        * full 23-bit address range
> > +        */
> > +       if (id != 0)
> > +               return -EINVAL;
> > +
> > +       rc = fsi_master_read(master, link, id, 0, &chip_id, sizeof(chip_id));
> > +       if (rc) {
> > +               dev_warn(&master->dev, "can't read slave %02x:%02x %d\n",
> > +                               link, id, rc);
> When I boot a system with this driver loaded, I get his warning:
>
> [    9.740000] usbhid: USB HID core driver
> [    9.840000]  fsi0: can't read slave 00:00 -5
> [    9.840000] NET: Registered protocol family 10
>
> Two things:
>
> There's a space in front of "fsi0".

Hi Joel,

Will correct.
> This warning isn't useful at that point. The slave is not readable as
> the FSI master is not present (the P9 hasn't been turned on). Can we
> avoid printing the warning at boot?

Yes agreed.  Will remove the warning in that case.

Thanks,
Chris
> Cheers,
>
> Joel
>
> > +               return -ENODEV;
> > +       }
> > +       chip_id = be32_to_cpu(chip_id);
> > +
> > +       crc = fsi_crc4(0, chip_id, 32);
> > +       if (crc) {
> > +               dev_warn(&master->dev, "slave %02x:%02x invalid chip id CRC!\n",
> > +                               link, id);
> > +               return -EIO;
> > +       }
> > +
> > +       dev_info(&master->dev, "fsi: found chip %08x at %02x:%02x:%02x\n",
> > +                       chip_id, master->idx, link, id);
> > +
> > +       /* We can communicate with a slave; create the slave device and
> > +        * register.
> > +        */
> > +       slave = kzalloc(sizeof(*slave), GFP_KERNEL);
> > +       if (!slave)
> > +               return -ENOMEM;
> > +
> > +       slave->master = master;
> > +       slave->dev.parent = &master->dev;
> > +       slave->dev.release = fsi_slave_release;
> > +       slave->link = link;
> > +       slave->id = id;
> > +       slave->size = FSI_SLAVE_SIZE_23b;
> > +
> > +       dev_set_name(&slave->dev, "slave@%02x:%02x", link, id);
> > +       rc = device_register(&slave->dev);
> > +       if (rc < 0) {
> > +               dev_warn(&master->dev, "failed to create slave device: %d\n",
> > +                               rc);
> > +               put_device(&slave->dev);
> > +               return rc;
> > +       }
> > +
> > +       /* todo: perform engine scan */
> >
> > -       return -ENODEV;
> > +       return rc;
> >   }
> >
> >   /* FSI master support */
> > --
> > 1.8.2.2