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

From: Joel Stanley
Date: Wed May 10 2017 - 03:31:32 EST

On Tue, Apr 11, 2017 at 5:16 AM, Christopher Bostic
<cbostic@xxxxxxxxxxxxxxxxxx> wrote:
> From: Jeremy Kerr <jk@xxxxxxxxxx>
>
> Now that we have fsi_slave devices, scan each for endpoints, and
> register them on the fsi bus.
>
> Includes contributions 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 | 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
>