Re: [PATCH 2/2] ARM: dts: omap5: Add dr_mode for dwc3

From: Dmitry Lifshitz
Date: Mon Sep 08 2014 - 08:33:11 EST

Hi Roger,

Thank you for a quick reply. See, my reply below.

On 09/08/2014 02:39 PM, Roger Quadros wrote:
On 09/08/2014 02:34 PM, Dmitry Lifshitz wrote:
Hi Felipe, Roger

On 04/16/2014 07:16 PM, Felipe Balbi wrote:
On Fri, Oct 11, 2013 at 05:46:12PM +0300, Roger Quadros wrote:
Hi,

On 10/10/2013 01:49 PM, Kishon Vijay Abraham I wrote:
From: George Cherian <george.cherian@xxxxxx>

Added dr_mode property in dwc3 and set its default mode to device.

If there is a specific reason why this is not set to "otg", we need
to explain it here.

AFAIK the port is meant to be used as OTG port.

we still don't have the workaround for dual role ports, I've been
working on it but still need to retest and make sure it's working fine
before merging upstream.



Does the OTG port suppose to work with OMAP5? I mean role switching mechanism?

I'm testing kernel v3.16 with OMAP5 based board (CM-T54).

If I set CONFIG_USB_DWC3_DUAL_ROLE, than nothing is going on when I plug some device/host cable into micro USB3.0 port (VBUS/ID detection with extcon events works fine).

CONFIG_USB_DWC3_HOST/CONFIG_USB_DWC3_GADGET bring port to appropriate mode and it works.

What is the purpose of setting dr_mode = "peripheral" in omap5.dtsi, since it is overridden by config options in dwc3_probe()?

If dual role works it should be "otg" then. I'm not sure why it was set to peripheral. Maybe the role switching mechanism
was not in place earlier.


This is what I have when setting dr_mode = "otg" (and compiling with CONFIG_USB_DWC3_DUAL_ROLE):

when load gadget driver and plugging host PC cable:

root@cm-debian:~# modprobe g_ether
using random self ethernet address
using random host ethernet address
usb0: HOST MAC fa:db:52:7f:95:c5
usb0: MAC be:75:8d:71:6d:02
using random self ethernet address
using random host ethernet address
g_ether gadget: Ethernet Gadget, version: Memorial Day 2008
g_ether gadget: g_ether ready
root@cm-debian:~# ------------[ cut here ]------------
WARNING: CPU: 0 PID: 65 at /home/lifshitz/workroot/git-repo/OMAP5/omap5-kernel/drivers/bus/omap_l3_noc.c:147 l3_handle_target.isra.2+0x230/0x27c()
44000000.ocp:L3 Standard Error: MASTER UN IDENTIFIED TARGET OCMRAM (Read): At Address: 0x00000000 : Data Access in User mode during Functional access
Modules linked in: usb_f_eem g_ether usb_f_rndis libcomposite u_ether configfs rfcomm ecb btmrvl_sdio btmrvl bluetooth mwifiex_sdio mwifiex dwc3 ahci_platform libahci_platform libahci libata snd_soc_cm_t54 ads7846 dwc3_omap extcon_palmas rtc_palmas extcon_class at24 snd_soc_wm8731 snd_soc_omap_mcbsp
CPU: 0 PID: 65 Comm: irq/39-palmas Tainted: G W 3.16.0-cm-t54+ #99
[<c00156d0>] (unwind_backtrace) from [<c00124ac>] (show_stack+0x10/0x14)
[<c00124ac>] (show_stack) from [<c05e29dc>] (dump_stack+0x74/0x8c)
[<c05e29dc>] (dump_stack) from [<c0037dbc>] (warn_slowpath_common+0x70/0x88)
[<c0037dbc>] (warn_slowpath_common) from [<c0037e68>] (warn_slowpath_fmt+0x30/0x40)
[<c0037e68>] (warn_slowpath_fmt) from [<c02d88b8>] (l3_handle_target.isra.2+0x230/0x27c)
[<c02d88b8>] (l3_handle_target.isra.2) from [<c02d89b0>] (l3_interrupt_handler+0xac/0x13c)
[<c02d89b0>] (l3_interrupt_handler) from [<c007ea00>] (handle_irq_event_percpu+0x7c/0x230)
[<c007ea00>] (handle_irq_event_percpu) from [<c007ebf8>] (handle_irq_event+0x44/0x64)
[<c007ebf8>] (handle_irq_event) from [<c0081b78>] (handle_fasteoi_irq+0xa8/0x134)
[<c0081b78>] (handle_fasteoi_irq) from [<c007e398>] (generic_handle_irq+0x20/0x30)
[<c007e398>] (generic_handle_irq) from [<c000f4ac>] (handle_IRQ+0x40/0x90)
[<c000f4ac>] (handle_IRQ) from [<c0008620>] (gic_handle_irq+0x2c/0x60)
[<c0008620>] (gic_handle_irq) from [<c05eacc0>] (__irq_svc+0x40/0x50)
Exception stack(0xec939d80 to 0xec939dc8)
9d80: ecb729b0 20000013 00000000 00000001 ecb72800 eca1e000 00000000 ec939e44
9da0: ec939ed0 20000013 ecb72818 ed005e14 ec939ec8 ec939dc8 bf015f54 c05ea548
9dc0: 80000013 ffffffff
[<c05eacc0>] (__irq_svc) from [<c05ea548>] (_raw_spin_unlock_irqrestore+0x1c/0x20)
[<c05ea548>] (_raw_spin_unlock_irqrestore) from [<bf015f54>] (extcon_update_state+0x144/0x1c4 [extcon_class])
[<bf015f54>] (extcon_update_state [extcon_class]) from [<bf023288>] (palmas_vbus_irq_handler+0x64/0xa0 [extcon_palmas])
[<bf023288>] (palmas_vbus_irq_handler [extcon_palmas]) from [<c00815a8>] (handle_nested_irq+0xa0/0x10c)
[<c00815a8>] (handle_nested_irq) from [<c03ab85c>] (regmap_irq_thread+0x184/0x300)
[<c03ab85c>] (regmap_irq_thread) from [<c007f8b8>] (irq_thread_fn+0x1c/0x40)
[<c007f8b8>] (irq_thread_fn) from [<c007f6a4>] (irq_thread+0x120/0x15c)
[<c007f6a4>] (irq_thread) from [<c0056434>] (kthread+0xdc/0xf0)
[<c0056434>] (kthread) from [<c000eb98>] (ret_from_fork+0x14/0x3c)
---[ end trace 3b365a734f7f3202 ]---
palmas-usb 48070000.i2c:palmas@48:palmas_usb: USB cable is attached



when plugging storage device:

root@cm-debian:~# dmesg | tail -n20
...
omap-dwc3 4a020000.omap_dwc3: ID GND
palmas-usb 48070000.i2c:palmas@48:palmas_usb: USB-HOST cable is attached
palmas-usb 48070000.i2c:palmas@48:palmas_usb: USB cable is attached

and nothing is going on.

Once again, when compiling with predefined role (CONFIG_USB_DWC3_HOST/CONFIG_USB_DWC3_GADGET) the port is functional in both modes.

I'm wondering, if dwc3_probe() calls
dwc3_core_init_mode() -> dwc3_set_mode() than why it is not required in dwc3_omap_set_mailbox()?



George any objections for "otg"?

cheers,
-roger
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Thanks,

Dmitry
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