Re: [PATCH v6 09/23] drivers/fsi: scan slaves & register devices

[Joel Stanley <joel@jms.id.au>]

On Tue, Apr 11, 2017 at 5:16 AM, Christopher Bostic
<cbostic@linux.vnet.ibm.com> wrote:
> From: Jeremy Kerr <jk@ozlabs.org>
>
> Now that we have fsi_slave devices, scan each for endpoints, and
> register them on the fsi bus.
>
> Includes contributions from Chris Bostic <cbostic@linux.vnet.ibm.com>
>
> Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
> Signed-off-by: Chris Bostic <cbostic@linux.vnet.ibm.com>
> Signed-off-by: Joel Stanley <joel@jms.id.au>
> ---
>  drivers/fsi/fsi-core.c | 127 +++++++++++++++++++++++++++++++++++++++++++++++--
>  include/linux/fsi.h    |   4 ++
>  2 files changed, 128 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
> index b7b138b..a8faa89 100644
> --- a/drivers/fsi/fsi-core.c
> +++ b/drivers/fsi/fsi-core.c
> @@ -21,6 +21,19 @@
>
>  #include "fsi-master.h"
>
> +#define FSI_SLAVE_CONF_NEXT_MASK       0x80000000
> +#define FSI_SLAVE_CONF_SLOTS_MASK      0x00ff0000
> +#define FSI_SLAVE_CONF_SLOTS_SHIFT     16
> +#define FSI_SLAVE_CONF_VERSION_MASK    0x0000f000
> +#define FSI_SLAVE_CONF_VERSION_SHIFT   12
> +#define FSI_SLAVE_CONF_TYPE_MASK       0x00000ff0
> +#define FSI_SLAVE_CONF_TYPE_SHIFT      4
> +#define FSI_SLAVE_CONF_CRC_SHIFT       4
> +#define FSI_SLAVE_CONF_CRC_MASK                0x0000000f
> +#define FSI_SLAVE_CONF_DATA_BITS       28

You could use GENAMSK for these. It would make it easier to check eg.
that 0x00ff0000 needs to be shifted by 16.


> +
> +static const int engine_page_size = 0x400;
> +
>  #define FSI_SLAVE_BASE                 0x800
>
>  /*
> @@ -61,6 +74,30 @@ static int fsi_master_read(struct fsi_master *master, int link,
>  static int fsi_master_write(struct fsi_master *master, int link,
>                 uint8_t slave_id, uint32_t addr, const void *val, size_t size);
>
> +/* FSI endpoint-device support */
> +
> +static void fsi_device_release(struct device *_device)
> +{
> +       struct fsi_device *device = to_fsi_dev(_device);
> +
> +       kfree(device);
> +}
> +
> +static struct fsi_device *fsi_create_device(struct fsi_slave *slave)
> +{
> +       struct fsi_device *dev;
> +
> +       dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> +       if (!dev)
> +               return NULL;
> +
> +       dev->dev.parent = &slave->dev;
> +       dev->dev.bus = &fsi_bus_type;
> +       dev->dev.release = fsi_device_release;
> +
> +       return dev;
> +}
> +
>  /* crc helpers */
>  static const uint8_t crc4_tab[] = {
>         0x0, 0x7, 0xe, 0x9, 0xb, 0xc, 0x5, 0x2,
> @@ -138,6 +175,91 @@ static int fsi_slave_write(struct fsi_slave *slave, uint32_t addr,
>                         addr, val, size);
>  }
>
> +static int fsi_slave_scan(struct fsi_slave *slave)
> +{
> +       uint32_t engine_addr;
> +       uint32_t conf;
> +       int rc, i;
> +
> +       /*
> +        * scan engines
> +        *
> +        * We keep the peek mode and slave engines for the core; so start
> +        * at the third slot in the configuration table. We also need to
> +        * skip the chip ID entry at the start of the address space.
> +        */
> +       engine_addr = engine_page_size * 3;
> +       for (i = 2; i < engine_page_size / sizeof(uint32_t); i++) {
> +               uint8_t slots, version, type, crc;
> +               struct fsi_device *dev;
> +
> +               rc = fsi_slave_read(slave, (i + 1) * sizeof(conf),
> +                               &conf, sizeof(conf));
> +               if (rc) {
> +                       dev_warn(&slave->dev,
> +                               "error reading slave registers\n");
> +                       return -1;
> +               }
> +               conf = be32_to_cpu(conf);
> +
> +               crc = fsi_crc4(0, conf, 32);
> +               if (crc) {
> +                       dev_warn(&slave->dev,
> +                               "crc error in slave register at 0x%04x\n",
> +                               i);
> +                       return -1;
> +               }
> +
> +               slots = (conf & FSI_SLAVE_CONF_SLOTS_MASK)
> +                       >> FSI_SLAVE_CONF_SLOTS_SHIFT;
> +               version = (conf & FSI_SLAVE_CONF_VERSION_MASK)
> +                       >> FSI_SLAVE_CONF_VERSION_SHIFT;
> +               type = (conf & FSI_SLAVE_CONF_TYPE_MASK)
> +                       >> FSI_SLAVE_CONF_TYPE_SHIFT;
> +
> +               /*
> +                * Unused address areas are marked by a zero type value; this
> +                * skips the defined address areas
> +                */
> +               if (type != 0 && slots != 0) {
> +
> +                       /* create device */
> +                       dev = fsi_create_device(slave);
> +                       if (!dev)
> +                               return -ENOMEM;
> +
> +                       dev->slave = slave;
> +                       dev->engine_type = type;
> +                       dev->version = version;
> +                       dev->unit = i;
> +                       dev->addr = engine_addr;
> +                       dev->size = slots * engine_page_size;
> +
> +                       dev_info(&slave->dev,
> +                       "engine[%i]: type %x, version %x, addr %x size %x\n",
> +                                       dev->unit, dev->engine_type, version,
> +                                       dev->addr, dev->size);

This produces a lot of noise in the kernel log. I suggest making it
drv_dbg if you require it. If you don't then remove it.

> +
> +                       dev_set_name(&dev->dev, "%02x:%02x:%02x:%02x",
> +                                       slave->master->idx, slave->link,
> +                                       slave->id, i - 2);
> +
> +                       rc = device_register(&dev->dev);
> +                       if (rc) {
> +                               dev_warn(&slave->dev, "add failed: %d\n", rc);
> +                               put_device(&dev->dev);
> +                       }
> +               }
> +
> +               engine_addr += slots * engine_page_size;
> +
> +               if (!(conf & FSI_SLAVE_CONF_NEXT_MASK))
> +                       break;
> +       }
> +
> +       return 0;
> +}
> +
>  /* Encode slave local bus echo delay */
>  static inline uint32_t fsi_smode_echodly(int x)
>  {
> @@ -253,9 +375,8 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
>                 return rc;
>         }
>
> -       /* todo: perform engine scan */
> -
> -       return rc;
> +       fsi_slave_scan(slave);
> +       return 0;

You don't check the return value of fsi_slave_scan.

>  }
>
>  /* FSI master support */
> diff --git a/include/linux/fsi.h b/include/linux/fsi.h
> index 273cbf6..efa55ba 100644
> --- a/include/linux/fsi.h
> +++ b/include/linux/fsi.h
> @@ -21,6 +21,10 @@ struct fsi_device {
>         struct device           dev;
>         u8                      engine_type;
>         u8                      version;
> +       u8                      unit;
> +       struct fsi_slave        *slave;
> +       uint32_t                addr;
> +       uint32_t                size;
>  };
>
>  struct fsi_device_id {
> --
> 1.8.2.2
>