On Okt 08 2018, Quentin Schulz <quentin.sch...@bootlin.com> wrote: > The Microsemi PHYs have multiple banks of registers (called pages). > Registers can only be accessed from one page, if we need a register from > another page, we need to switch the page and the registers of all other > pages are not accessible anymore. > > Basically, to read register 5 from page 0, 1, 2, etc., you do the same > phy_read(phydev, 5); but you need to set the desired page beforehand. > > In order to guarantee that two concurrent functions do not change the > page, we need to do some locking per page. This can be achieved with the > use of phy_select_page and phy_restore_page functions but phy_write/read > calls in-between those two functions shall be replaced by their > lock-free alternative __phy_write/read. > > Let's migrate this driver to those functions.
This has some serious locking problem. [<0>] __schedule+0x25e/0x74c [<0>] schedule+0x1a/0x58 [<0>] schedule_preempt_disabled+0xc/0x14 [<0>] __mutex_lock.isra.0+0x10e/0x22e [<0>] __mutex_lock_slowpath+0xe/0x16 [<0>] mutex_lock+0x22/0x2a [<0>] mdiobus_read+0x36/0x60 [<0>] vsc85xx_config_init+0x4c/0x1e2 [<0>] phy_init_hw+0x3c/0x52 [<0>] phy_attach_direct+0xec/0x1dc [<0>] phy_connect_direct+0x1a/0x56 [<0>] macb_probe+0x800/0xb5e [macb] [<0>] platform_drv_probe+0x3e/0x7e [<0>] really_probe+0xba/0x310 [<0>] driver_probe_device+0x54/0xf2 [<0>] __driver_attach+0xde/0x106 [<0>] bus_for_each_dev+0x4a/0x72 [<0>] driver_attach+0x1a/0x22 [<0>] bus_add_driver+0x1ce/0x212 [<0>] driver_register+0x3a/0xd0 [<0>] __platform_driver_register+0x3a/0x42 [<0>] macb_driver_init+0x20/0x28 [macb] [<0>] do_one_initcall+0x48/0x128 [<0>] do_init_module+0x4a/0x186 [<0>] load_module+0xd6a/0xe6a [<0>] sys_finit_module+0xc6/0xfc [<0>] check_syscall_nr+0x22/0x22 Andreas. -- Andreas Schwab, SUSE Labs, sch...@suse.de GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7 "And now for something completely different."
