| From df6b074dbe248d8c43a82131e8fd429e401841a5 Mon Sep 17 00:00:00 2001 |
| From: Merlijn Wajer <merlijn@wizzup.org> |
| Date: Mon, 5 Mar 2018 11:35:10 -0600 |
| Subject: usb: musb: call pm_runtime_{get,put}_sync before reading vbus registers |
| |
| From: Merlijn Wajer <merlijn@wizzup.org> |
| |
| commit df6b074dbe248d8c43a82131e8fd429e401841a5 upstream. |
| |
| Without pm_runtime_{get,put}_sync calls in place, reading |
| vbus status via /sys causes the following error: |
| |
| Unhandled fault: external abort on non-linefetch (0x1028) at 0xfa0ab060 |
| pgd = b333e822 |
| [fa0ab060] *pgd=48011452(bad) |
| |
| [<c05261b0>] (musb_default_readb) from [<c0525bd0>] (musb_vbus_show+0x58/0xe4) |
| [<c0525bd0>] (musb_vbus_show) from [<c04c0148>] (dev_attr_show+0x20/0x44) |
| [<c04c0148>] (dev_attr_show) from [<c0259f74>] (sysfs_kf_seq_show+0x80/0xdc) |
| [<c0259f74>] (sysfs_kf_seq_show) from [<c0210bac>] (seq_read+0x250/0x448) |
| [<c0210bac>] (seq_read) from [<c01edb40>] (__vfs_read+0x1c/0x118) |
| [<c01edb40>] (__vfs_read) from [<c01edccc>] (vfs_read+0x90/0x144) |
| [<c01edccc>] (vfs_read) from [<c01ee1d0>] (SyS_read+0x3c/0x74) |
| [<c01ee1d0>] (SyS_read) from [<c0106fe0>] (ret_fast_syscall+0x0/0x54) |
| |
| Solution was suggested by Tony Lindgren <tony@atomide.com>. |
| |
| Signed-off-by: Merlijn Wajer <merlijn@wizzup.org> |
| Acked-by: Tony Lindgren <tony@atomide.com> |
| Signed-off-by: Bin Liu <b-liu@ti.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/usb/musb/musb_core.c | 2 ++ |
| 1 file changed, 2 insertions(+) |
| |
| --- a/drivers/usb/musb/musb_core.c |
| +++ b/drivers/usb/musb/musb_core.c |
| @@ -1774,6 +1774,7 @@ musb_vbus_show(struct device *dev, struc |
| int vbus; |
| u8 devctl; |
| |
| + pm_runtime_get_sync(dev); |
| spin_lock_irqsave(&musb->lock, flags); |
| val = musb->a_wait_bcon; |
| vbus = musb_platform_get_vbus_status(musb); |
| @@ -1787,6 +1788,7 @@ musb_vbus_show(struct device *dev, struc |
| vbus = 0; |
| } |
| spin_unlock_irqrestore(&musb->lock, flags); |
| + pm_runtime_put_sync(dev); |
| |
| return sprintf(buf, "Vbus %s, timeout %lu msec\n", |
| vbus ? "on" : "off", val); |