On Tue, Dec 06, 2016 at 06:14:35PM -0600, Chris Bostic wrote:
> From: Chris Bostic <cbostic@xxxxxxxxxx>
>
> Allow a master to undo a previous scan. Should a master scan a bus
> twice it will need to ensure it doesn't double register any
> previously detected device.
>
> Signed-off-by: Chris Bostic <cbostic@xxxxxxxxxx>
> ---
> drivers/fsi/fsi-core.c | 36 +++++++++++++++++++++++++++++++++++-
> drivers/fsi/fsi-master.h | 2 ++
> include/linux/fsi.h | 1 +
> 3 files changed, 38 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
> index a28434b..8ccfe50 100644
> --- a/drivers/fsi/fsi-core.c
> +++ b/drivers/fsi/fsi-core.c
> @@ -41,6 +41,8 @@
> static atomic_t master_idx = ATOMIC_INIT(-1);
>
> struct fsi_slave {
> + struct list_head list_link; /* Master's list of slaves */
> + struct list_head my_engines;
> struct device dev;
> struct fsi_master *master;
> int link;
> @@ -196,6 +198,8 @@ static int fsi_slave_scan(struct fsi_slave *slave)
> uint32_t conf;
> int rc, i;
>
> + INIT_LIST_HEAD(&slave->my_engines);
> +
> /*
> * scan engines
> *
> @@ -264,7 +268,9 @@ static int fsi_slave_scan(struct fsi_slave *slave)
> if (rc) {
> dev_warn(&slave->dev, "add failed: %d\n", rc);
> put_device(&dev->dev);
> + continue;
> }
> + list_add(&dev->link, &slave->my_engines);
> }
>
> engine_addr += slots * engine_page_size;
> @@ -357,7 +363,7 @@ static int fsi_slave_init(struct fsi_master *master,
> put_device(&slave->dev);
> return rc;
> }
> -
> + list_add(&slave->list_link, &master->my_slaves);
> fsi_slave_scan(slave);
> return 0;
> }
> @@ -388,6 +394,11 @@ static int fsi_master_scan(struct fsi_master *master)
> int link, slave_id, rc;
> uint32_t smode;
>
> + if (!master->slave_list) {
> + INIT_LIST_HEAD(&master->my_slaves);
> + master->slave_list = true;
> + }
> +
> for (link = 0; link < master->n_links; link++) {
> rc = fsi_master_link_enable(master, link);
> if (rc) {
> @@ -423,9 +434,31 @@ static int fsi_master_scan(struct fsi_master *master)
> return 0;
> }
>
> +static void fsi_master_unscan(struct fsi_master *master)
> +{
> + struct fsi_slave *slave, *slave_tmp;
> + struct fsi_device *fsi_dev, *fsi_dev_tmp;
> +
> + if (!master->slave_list)
> + return;
> +
> + list_for_each_entry_safe(slave, slave_tmp, &master->my_slaves,
> + list_link) {
> + list_del(&slave->list_link);
> + list_for_each_entry_safe(fsi_dev, fsi_dev_tmp,
> + &slave->my_engines, link) {
> + list_del(&fsi_dev->link);
> + put_device(&fsi_dev->dev);
> + }
> + device_unregister(&slave->dev);
> + }
> + master->slave_list = false;
> +}
> +
> int fsi_master_register(struct fsi_master *master)
> {
> master->idx = atomic_inc_return(&master_idx);
> + master->slave_list = false;
> get_device(master->dev);
> fsi_master_scan(master);
> return 0;
> @@ -434,6 +467,7 @@ int fsi_master_register(struct fsi_master *master)
>
> void fsi_master_unregister(struct fsi_master *master)
> {
> + fsi_master_unscan(master);
> put_device(master->dev);
> }
> EXPORT_SYMBOL_GPL(fsi_master_unregister);
> diff --git a/drivers/fsi/fsi-master.h b/drivers/fsi/fsi-master.h
> index 56aad0e..454af2b 100644
> --- a/drivers/fsi/fsi-master.h
> +++ b/drivers/fsi/fsi-master.h
> @@ -20,6 +20,8 @@
> #include <linux/device.h>
>
> struct fsi_master {
> + struct list_head my_slaves;
> + bool slave_list;
> struct device *dev;
> int idx;
> int n_links;
> diff --git a/include/linux/fsi.h b/include/linux/fsi.h
> index 66bce48..924502b 100644
> --- a/include/linux/fsi.h
> +++ b/include/linux/fsi.h
> @@ -18,6 +18,7 @@
> #include <linux/device.h>
>
> struct fsi_device {
> + struct list_head link; /* for slave's list */
Can't you use the device list on the bus instead? Putting a device on
multiple lists gets tricky very quickly :(
thanks,
greg k-h
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