[PATCH v2] dm: uclass: don't assign aliased seq numbers

[Michael Walle]

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.

Cc: Thomas Fitzsimmons <fitzsim at fitzsim.org>
Cc: Michal Simek <michal.simek at xilinx.com>
Signed-off-by: Michael Walle <michael at walle.cc>
Reviewed-by: Alex Marginean <alexandru.marginean at nxp.com>
Tested-by: Alex Marginean <alexandru.marginean at nxp.com>
Acked-by: Vladimir Oltean <olteanv at gmail.com>
---

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.

changes since v1:
 - move notice about superfluous commits from commit message to this
   section.
 - fix the comment style

 drivers/core/uclass.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/core/uclass.c b/drivers/core/uclass.c
index c520ef113a..3c216221e0 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 +694,17 @@ 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
+		 * 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)
-- 
2.20.1