On Wed, Aug 19, 2020 at 05:03:32PM +0200, Jerome Brunet wrote: > > On Mon 13 Jul 2020 at 18:05, Dan Robertson wrote: > > > The reset is a shared reset line, but reset_control_reset is still used > > and reset_control_deassert is not guaranteed to have been called before > > the first reset_control_assert call. When suspending the following > > warning may be seen: > > And now the same type of warning maybe seen on boot. This is > happening for me on the libretech-cc (s905x - gxl). > > [ 1.863469] ------------[ cut here ]------------ > [ 1.867914] WARNING: CPU: 1 PID: 16 at drivers/reset/core.c:309 reset_control_reset+0x130/0x150 > [ 1.876525] Modules linked in: > [ 1.879548] CPU: 1 PID: 16 Comm: kworker/1:0 Not tainted 5.9.0-rc1-00167-ga2e4e3a34775 #64 > [ 1.887737] Hardware name: Libre Computer AML-S905X-CC V2 (DT) > [ 1.893525] Workqueue: events deferred_probe_work_func > [ 1.898607] pstate: 80000005 (Nzcv daif -PAN -UAO BTYPE=--) > [ 1.904126] pc : reset_control_reset+0x130/0x150 > [ 1.908700] lr : phy_meson_gxl_usb2_init+0x24/0x70 > [ 1.913439] sp : ffff8000123ebad0 > [ 1.916717] x29: ffff8000123ebad0 x28: 0000000000000000 > [ 1.921978] x27: ffff00007c4b1ac8 x26: ffff00007c4b1ab0 > [ 1.927239] x25: ffff00007fc149b0 x24: ffff00007c4b1ab0 > [ 1.932500] x23: ffff00007cd03800 x22: ffff800011fb9000 > [ 1.937761] x21: ffff00007c60db08 x20: ffff00007c468a80 > [ 1.943023] x19: ffff00007c466b00 x18: ffffffffffffffff > [ 1.948284] x17: 0000000000000000 x16: 000000000000000e > [ 1.953545] x15: ffff800011fb9948 x14: ffffffffffffffff > [ 1.958806] x13: ffffffff00000000 x12: ffffffffffffffff > [ 1.964068] x11: 0000000000000020 x10: 7f7f7f7f7f7f7f7f > [ 1.969329] x9 : 78676f2c32617274 x8 : 0000000000000000 > [ 1.974590] x7 : ffffffffffffffff x6 : 0000000000000000 > [ 1.979851] x5 : 0000000000000000 x4 : 0000000000000000 > [ 1.985112] x3 : 0000000000000000 x2 : ffff8000107aa370 > [ 1.990374] x1 : 0000000000000001 x0 : 0000000000000001 > [ 1.995636] Call trace: > [ 1.998054] reset_control_reset+0x130/0x150 > [ 2.002279] phy_meson_gxl_usb2_init+0x24/0x70 > [ 2.006677] phy_init+0x78/0xd0 > [ 2.009784] dwc3_meson_g12a_probe+0x2c8/0x560 > [ 2.014182] platform_drv_probe+0x58/0xa8 > [ 2.018149] really_probe+0x114/0x3d8 > [ 2.021770] driver_probe_device+0x5c/0xb8 > [ 2.025824] __device_attach_driver+0x98/0xb8 > [ 2.030138] bus_for_each_drv+0x74/0xd8 > [ 2.033933] __device_attach+0xec/0x148 > [ 2.037726] device_initial_probe+0x24/0x30 > [ 2.041868] bus_probe_device+0x9c/0xa8 > [ 2.045663] deferred_probe_work_func+0x7c/0xb8 > [ 2.050150] process_one_work+0x1f0/0x4b0 > [ 2.054115] worker_thread+0x210/0x480 > [ 2.057824] kthread+0x158/0x160 > [ 2.061017] ret_from_fork+0x10/0x18 > [ 2.064550] ---[ end trace 94d737efe593c6f6 ]--- > [ 2.069158] phy phy-d0078000.phy.0: phy init failed --> -22 > [ 2.074858] dwc3-meson-g12a: probe of d0078080.usb failed with error -22 > > This breaks USB on this device. reverting the change brings it back. > > Looking at the reset framework code, I don't think drivers sharing the > same reset line should mix using reset_control_reset() VS > reset_control_assert()/reset_control_deassert() > Thanks for finding this. I was only able to test on the Odroid N2 > > > > WARNING: CPU: 1 PID: 5530 at drivers/reset/core.c:355 reset_control_assert+0x184/0x19c > > Hardware name: Hardkernel ODROID-N2 (DT) > > [..] > > pc : reset_control_assert+0x184/0x19c > > lr : dwc3_meson_g12a_suspend+0x68/0x7c > > [..] > > Call trace: > > reset_control_assert+0x184/0x19c > > dwc3_meson_g12a_suspend+0x68/0x7c > > platform_pm_suspend+0x28/0x54 > > __device_suspend+0x590/0xabc > > dpm_suspend+0x104/0x404 > > dpm_suspend_start+0x84/0x1bc > > suspend_devices_and_enter+0xc4/0x4fc > > pm_suspend+0x198/0x2d4 > > > > Fixes: 6d9fa35a347a87 ("usb: dwc3: meson-g12a: get the reset as shared") > > Signed-off-by: Dan Robertson > > --- > > drivers/usb/dwc3/dwc3-meson-g12a.c | 15 +++++++++------ > > 1 file changed, 9 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/usb/dwc3/dwc3-meson-g12a.c b/drivers/usb/dwc3/dwc3-meson-g12a.c > > index 1f7f4d88ed9d..88b75b5a039c 100644 > > --- a/drivers/usb/dwc3/dwc3-meson-g12a.c > > +++ b/drivers/usb/dwc3/dwc3-meson-g12a.c > > @@ -737,13 +737,13 @@ static int dwc3_meson_g12a_probe(struct platform_device *pdev) > > goto err_disable_clks; > > } > > > > - ret = reset_control_reset(priv->reset); > > + ret = reset_control_deassert(priv->reset); > > The change introduced here is significant. If the reset is not initially > asserted, it never will be before the life of the device. > > This means that Linux will have to deal which whatever state is left by the > bootloader. This looks sketchy ... > > I think the safer way solve the problem here would be to keep using > reset_control_reset() and introduce a new API in the reset > framework to decrement the reset line "triggered_count" > (reset_control_clear() ??) I have very limited experience with reset controls, but phy_meson_gxl_usb2_init calls reset_control_reset on a shared reset line, which should not be done according to the reset control docs. Would removing the use of reset_control_reset, or using reset_control_(de)assert in phy_meson_gxl_usb2_init also resolve the issue? > That way, if all device using the reset line go to suspend, the line will > be "reset-able" again by the first device coming out of suspend ? > > Philip, would you be ok with such new API ? > > In the meantime, I think this change should be reverted. A warning on > suspend seems less critical than a regression breaking USB completly. The reset_control_(de)assert() calls could also be removed from the suspend/resume calls for now. > > if (ret) > > - goto err_disable_clks; > > + goto err_assert_reset; > > > > ret = dwc3_meson_g12a_get_phys(priv); > > if (ret) > > - goto err_disable_clks; > > + goto err_assert_reset; > > > > ret = priv->drvdata->setup_regmaps(priv, base); > > if (ret) > > @@ -752,7 +752,7 @@ static int dwc3_meson_g12a_probe(struct platform_device *pdev) > > if (priv->vbus) { > > ret = regulator_enable(priv->vbus); > > if (ret) > > - goto err_disable_clks; > > + goto err_assert_reset; > > } > > > > /* Get dr_mode */ > > @@ -765,13 +765,13 @@ static int dwc3_meson_g12a_probe(struct platform_device *pdev) > > > > ret = priv->drvdata->usb_init(priv); > > if (ret) > > - goto err_disable_clks; > > + goto err_assert_reset; > > > > /* Init PHYs */ > > for (i = 0 ; i < PHY_COUNT ; ++i) { > > ret = phy_init(priv->phys[i]); > > if (ret) > > - goto err_disable_clks; > > + goto err_assert_reset; > > } > > > > /* Set PHY Power */ > > @@ -809,6 +809,9 @@ static int dwc3_meson_g12a_probe(struct platform_device *pdev) > > for (i = 0 ; i < PHY_COUNT ; ++i) > > phy_exit(priv->phys[i]); > > > > +err_assert_reset: > > + reset_control_assert(priv->reset); > > + > > err_disable_clks: > > clk_bulk_disable_unprepare(priv->drvdata->num_clks, > > priv->drvdata->clks); > > > > > > _______________________________________________ > > linux-amlogic mailing list > > linux-amlogic@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-amlogic >