[PATCH] dm: uclass: don't assign aliased seq numbers

[Alexandru Marginean]

Hi Michael,

On 12/18/2019 5:42 PM, Michael Walle wrote:
> If there are aliases for an uclass, set the base for the "dynamically"
> allocated numbers next to the highest alias.
> 
> Please note, that this might lead to holes in the sequences, depending
> on the device tree. For example if there is only an alias "ethernet1",
> the next device seq number would be 2.
> 
> In particular this fixes a problem with boards which are using ethernet
> aliases but also might have network add-in cards like the E1000. If the
> board is started with the add-in card and depending on the order of the
> drivers, the E1000 might occupy the first ethernet device and mess up
> all the hardware addresses, because the devices are now shifted by one.
> 
> As a side effect, this should also make the following commits
> superfluous:
>   - 7f3289bf6d ("dm: device: Request next sequence number")
>   - 61607225d1 ("i2c: Fill req_seq in i2c_post_bind()")
>     Although I don't understand the root cause of the said problem.
> 
> Thomas, Michal, could you please test this and then I'd add a second
> patch removing the old code.
> 
> Cc: Thomas Fitzsimmons <fitzsim at fitzsim.org>
> Cc: Michal Simek <michal.simek at xilinx.com>
> 
> Signed-off-by: Michael Walle <michael at walle.cc>
> ---
>   drivers/core/uclass.c | 20 ++++++++++++++------
>   1 file changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/core/uclass.c b/drivers/core/uclass.c
> index c520ef113a..c3b325141a 100644
> --- a/drivers/core/uclass.c
> +++ b/drivers/core/uclass.c
> @@ -675,13 +675,14 @@ int uclass_unbind_device(struct udevice *dev)
>   
>   int uclass_resolve_seq(struct udevice *dev)
>   {
> +	struct uclass *uc = dev->uclass;
> +	struct uclass_driver *uc_drv = uc->uc_drv;
>   	struct udevice *dup;
> -	int seq;
> +	int seq = 0;
>   	int ret;
>   
>   	assert(dev->seq == -1);
> -	ret = uclass_find_device_by_seq(dev->uclass->uc_drv->id, dev->req_seq,
> -					false, &dup);
> +	ret = uclass_find_device_by_seq(uc_drv->id, dev->req_seq, false, &dup);
>   	if (!ret) {
>   		dm_warn("Device '%s': seq %d is in use by '%s'\n",
>   			dev->name, dev->req_seq, dup->name);
> @@ -693,9 +694,16 @@ int uclass_resolve_seq(struct udevice *dev)
>   		return ret;
>   	}
>   
> -	for (seq = 0; seq < DM_MAX_SEQ; seq++) {
> -		ret = uclass_find_device_by_seq(dev->uclass->uc_drv->id, seq,
> -						false, &dup);
> +	if (CONFIG_IS_ENABLED(DM_SEQ_ALIAS) &&
> +	    (uc_drv->flags & DM_UC_FLAG_SEQ_ALIAS)) {
> +		/* dev_read_alias_highest_id() will return -1 if there no

nits: there /is/ no and multi-line comment starts with just /* on the 
1st line

> +		 * alias. Thus we can always add one.
> +		 */
> +		seq = dev_read_alias_highest_id(uc_drv->name) + 1;
> +	}
> +
> +	for (; seq < DM_MAX_SEQ; seq++) {
> +		ret = uclass_find_device_by_seq(uc_drv->id, seq, false, &dup);
>   		if (ret == -ENODEV)
>   			break;
>   		if (ret)
> 


Reviewed-by: Alex Marginean <alexandru.marginean at nxp.com>
Tested-by: Alex Marginean <alexandru.marginean at nxp.com>

This looks nice.
One thing I noticed is that 'dm tree' indexes now don't match dev->seq 
which can be a bit confusing.  The index is produced by 
dev_get_uclass_index, which in effect counts devices in the uclass.  Any 
issue if 'dm tree' prints dev->seq instead and maybe call the column Seq 
rather than Index?

Thanks!
Alex