kernel/drivers/net/dsa/b53/b53_srab.c, branch 0x221E-v0.0.1-v6.19

net: dsa: Switch back to struct platform_driver::remove()

2024-10-04T23:39:57Z

After commit 0edb555a65d1 ("platform: Make platform_driver::remove() return void") .remove() is (again) the right callback to implement for platform drivers. Convert all platform drivers below drivers/net/dsa to use .remove(), with the eventual goal to drop struct platform_driver::remove_new(). As .remove() and .remove_new() have the same prototypes, conversion is done by just changing the structure member name in the driver initializer. Signed-off-by: Uwe Kleine-König Reviewed-by: Andrew Lunn Link: https://patch.msgid.link/36da477cb9fa0bffec32d50c2cf3d18e94a0e7e3.1727949050.git.u.kleine-koenig@baylibre.com Signed-off-by: Jakub Kicinski

net: dsa: b53: Convert to platform remove callback returning void

2023-09-20T09:25:57Z

The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is ignored (apart from emitting a warning) and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new() which already returns void. Eventually after all drivers are converted, .remove_new() is renamed to .remove(). Trivially convert these drivers from always returning zero in the remove callback to the void returning variant. Signed-off-by: Uwe Kleine-König Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: b53: remove unnecessary set_drvdata()

2022-09-23T02:30:34Z

Remove unnecessary set_drvdata(NULL) function in ->remove(), the driver_data will be set to NULL in device_unbind_cleanup() after calling ->remove(). Signed-off-by: Yang Yingliang Signed-off-by: Jakub Kicinski

net: dsa: b53: convert to phylink_pcs

2022-05-01T16:51:06Z

Convert B53 to use phylink_pcs for the serdes rather than hooking it into the MAC-layer callbacks. Fixes: 81c1681cbb9f ("net: dsa: b53: mark as non-legacy") Reviewed-by: Florian Fainelli Tested-by: Florian Fainelli Signed-off-by: Russell King (Oracle) Signed-off-by: David S. Miller

net: dsa: b53: switch to using phylink_generic_validate()

2022-02-22T11:03:02Z

Switch the Broadcom b53 driver to using the phylink_generic_validate() implementation by removing its own .phylink_validate method and associated code. Signed-off-by: Russell King (Oracle) Signed-off-by: David S. Miller

net: dsa: b53: populate supported_interfaces and mac_capabilities

2022-02-22T11:03:02Z

Populate the supported interfaces and MAC capabilities for the Broadcom B53 DSA switches in preparation to using these for the generic validation functionality. The interface modes are derived from: - b53_serdes_phylink_validate() - SRAB mux configuration Signed-off-by: Russell King (Oracle) Signed-off-by: David S. Miller

net: dsa: be compatible with masters which unregister on shutdown

2021-09-19T11:08:37Z

Lino reports that on his system with bcmgenet as DSA master and KSZ9897 as a switch, rebooting or shutting down never works properly. What does the bcmgenet driver have special to trigger this, that other DSA masters do not? It has an implementation of ->shutdown which simply calls its ->remove implementation. Otherwise said, it unregisters its network interface on shutdown. This message can be seen in a loop, and it hangs the reboot process there: unregister_netdevice: waiting for eth0 to become free. Usage count = 3 So why 3? A usage count of 1 is normal for a registered network interface, and any virtual interface which links itself as an upper of that will increment it via dev_hold. In the case of DSA, this is the call path: dsa_slave_create -> netdev_upper_dev_link -> __netdev_upper_dev_link -> __netdev_adjacent_dev_insert -> dev_hold So a DSA switch with 3 interfaces will result in a usage count elevated by two, and netdev_wait_allrefs will wait until they have gone away. Other stacked interfaces, like VLAN, watch NETDEV_UNREGISTER events and delete themselves, but DSA cannot just vanish and go poof, at most it can unbind itself from the switch devices, but that must happen strictly earlier compared to when the DSA master unregisters its net_device, so reacting on the NETDEV_UNREGISTER event is way too late. It seems that it is a pretty established pattern to have a driver's ->shutdown hook redirect to its ->remove hook, so the same code is executed regardless of whether the driver is unbound from the device, or the system is just shutting down. As Florian puts it, it is quite a big hammer for bcmgenet to unregister its net_device during shutdown, but having a common code path with the driver unbind helps ensure it is well tested. So DSA, for better or for worse, has to live with that and engage in an arms race of implementing the ->shutdown hook too, from all individual drivers, and do something sane when paired with masters that unregister their net_device there. The only sane thing to do, of course, is to unlink from the master. However, complications arise really quickly. The pattern of redirecting ->shutdown to ->remove is not unique to bcmgenet or even to net_device drivers. In fact, SPI controllers do it too (see dspi_shutdown -> dspi_remove), and presumably, I2C controllers and MDIO controllers do it too (this is something I have not researched too deeply, but even if this is not the case today, it is certainly plausible to happen in the future, and must be taken into consideration). Since DSA switches might be SPI devices, I2C devices, MDIO devices, the insane implication is that for the exact same DSA switch device, we might have both ->shutdown and ->remove getting called. So we need to do something with that insane environment. The pattern I've come up with is "if this, then not that", so if either ->shutdown or ->remove gets called, we set the device's drvdata to NULL, and in the other hook, we check whether the drvdata is NULL and just do nothing. This is probably not necessary for platform devices, just for devices on buses, but I would really insist for consistency among drivers, because when code is copy-pasted, it is not always copy-pasted from the best sources. So depending on whether the DSA switch's ->remove or ->shutdown will get called first, we cannot really guarantee even for the same driver if rebooting will result in the same code path on all platforms. But nonetheless, we need to do something minimally reasonable on ->shutdown too to fix the bug. Of course, the ->remove will do more (a full teardown of the tree, with all data structures freed, and this is why the bug was not caught for so long). The new ->shutdown method is kept separate from dsa_unregister_switch not because we couldn't have unregistered the switch, but simply in the interest of doing something quick and to the point. The big question is: does the DSA switch's ->shutdown get called earlier than the DSA master's ->shutdown? If not, there is still a risk that we might still trigger the WARN_ON in unregister_netdevice that says we are attempting to unregister a net_device which has uppers. That's no good. Although the reference to the master net_device won't physically go away even if DSA's ->shutdown comes afterwards, remember we have a dev_hold on it. The answer to that question lies in this comment above device_link_add: * A side effect of the link creation is re-ordering of dpm_list and the * devices_kset list by moving the consumer device and all devices depending * on it to the ends of these lists (that does not happen to devices that have * not been registered when this function is called). so the fact that DSA uses device_link_add towards its master is not exactly for nothing. device_shutdown() walks devices_kset from the back, so this is our guarantee that DSA's shutdown happens before the master's shutdown. Fixes: 2f1e8ea726e9 ("net: dsa: link interfaces with the DSA master to get rid of lockdep warnings") Link: https://lore.kernel.org/netdev/20210909095324.12978-1-LinoSanfilippo@gmx.de/ Reported-by: Lino Sanfilippo Signed-off-by: Vladimir Oltean Tested-by: Andrew Lunn Signed-off-by: David S. Miller

net: dsa: b53: remove redundant null check on dev

2021-06-15T18:28:01Z

The pointer dev can never be null, the null check is redundant and can be removed. Cleans up a static analysis warning that pointer priv is dereferencing dev before dev is being null checked. Addresses-Coverity: ("Dereference before null check") Signed-off-by: Colin Ian King Acked-by: Florian Fainelli Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2020-05-24T20:47:27Z

The MSCC bug fix in 'net' had to be slightly adjusted because the register accesses are done slightly differently in net-next. Signed-off-by: David S. Miller

net: Fix return value about devm_platform_ioremap_resource()

2020-05-23T23:28:25Z

When call function devm_platform_ioremap_resource(), we should use IS_ERR() to check the return value and return PTR_ERR() if failed. Signed-off-by: Tiezhu Yang Signed-off-by: David S. Miller