| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <0d8de3e0-341b-f751-909d-22aa16e91717@samsung.com>
Date: Tue, 3 Aug 2021 11:40:00 +0200
From: Marek Szyprowski <m.szyprowski@...sung.com>
To: Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"linux-samsung-soc@...r.kernel.org"
<linux-samsung-soc@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc: Felipe Balbi <felipe.balbi@...ux.intel.com>,
Artur Petrosyan <Arthur.Petrosyan@...opsys.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
Krzysztof Kozlowski <krzk@...nel.org>
Subject: Re: [PATCH] usb: dwc2: Skip clock gating on Samsung SoCs
Hi Minas,
On 16.07.2021 16:54, Minas Harutyunyan wrote:
> On 7/16/2021 9:01 AM, Marek Szyprowski wrote:
>> Commit 0112b7ce68ea ("usb: dwc2: Update dwc2_handle_usb_suspend_intr
>> function.") changed the way the driver handles power down modes in a such
>> way that it uses clock gating when no other power down mode is available.
>>
>> This however doesn't work well on the DWC2 implementation used on the
>> Samsung SoCs. When a clock gating is enabled, system hangs. It looks that
>> the proper clock gating requires some additional glue code in the shared
>> USB2 PHY and/or Samsung glue code for the DWC2. To restore driver
>> operation on the Samsung SoCs simply skip enabling clock gating mode
>> until one finds what is really needed to make it working reliably.
>>
>> Fixes: 0112b7ce68ea ("usb: dwc2: Update dwc2_handle_usb_suspend_intr function.")
>> Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
>> ---
>> drivers/usb/dwc2/core.h | 4 ++++
>> drivers/usb/dwc2/core_intr.c | 3 ++-
>> drivers/usb/dwc2/hcd.c | 6 ++++--
>> drivers/usb/dwc2/params.c | 1 +
>> 4 files changed, 11 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
>> index ab6b815e0089..483de2bbfaab 100644
>> --- a/drivers/usb/dwc2/core.h
>> +++ b/drivers/usb/dwc2/core.h
>> @@ -383,6 +383,9 @@ enum dwc2_ep0_state {
>> * 0 - No (default)
>> * 1 - Partial power down
>> * 2 - Hibernation
>> + * @no_clock_gating: Specifies whether to avoid clock gating feature.
>> + * 0 - No (use clock gating)
>> + * 1 - Yes (avoid it)
>> * @lpm: Enable LPM support.
>> * 0 - No
>> * 1 - Yes
>> @@ -480,6 +483,7 @@ struct dwc2_core_params {
>> #define DWC2_POWER_DOWN_PARAM_NONE 0
>> #define DWC2_POWER_DOWN_PARAM_PARTIAL 1
>> #define DWC2_POWER_DOWN_PARAM_HIBERNATION 2
>> + bool no_clock_gating;
>>
>> bool lpm;
>> bool lpm_clock_gating;
>> diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
>> index a5ab03808da6..a5c52b237e72 100644
>> --- a/drivers/usb/dwc2/core_intr.c
>> +++ b/drivers/usb/dwc2/core_intr.c
>> @@ -556,7 +556,8 @@ static void dwc2_handle_usb_suspend_intr(struct dwc2_hsotg *hsotg)
>> * If neither hibernation nor partial power down are supported,
>> * clock gating is used to save power.
>> */
>> - dwc2_gadget_enter_clock_gating(hsotg);
>> + if (!hsotg->params.no_clock_gating)
>> + dwc2_gadget_enter_clock_gating(hsotg);
>> }
>>
>> /*
>> diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
>> index 035d4911a3c3..2a7828971d05 100644
>> --- a/drivers/usb/dwc2/hcd.c
>> +++ b/drivers/usb/dwc2/hcd.c
>> @@ -3338,7 +3338,8 @@ int dwc2_port_suspend(struct dwc2_hsotg *hsotg, u16 windex)
>> * If not hibernation nor partial power down are supported,
>> * clock gating is used to save power.
>> */
>> - dwc2_host_enter_clock_gating(hsotg);
>> + if (!hsotg->params.no_clock_gating)
>> + dwc2_host_enter_clock_gating(hsotg);
>> break;
>> }
>>
>> @@ -4402,7 +4403,8 @@ static int _dwc2_hcd_suspend(struct usb_hcd *hcd)
>> * If not hibernation nor partial power down are supported,
>> * clock gating is used to save power.
>> */
>> - dwc2_host_enter_clock_gating(hsotg);
>> + if (!hsotg->params.no_clock_gating)
>> + dwc2_host_enter_clock_gating(hsotg);
>>
>> /* After entering suspend, hardware is not accessible */
>> clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
>> diff --git a/drivers/usb/dwc2/params.c b/drivers/usb/dwc2/params.c
>> index 67c5eb140232..59e119345994 100644
>> --- a/drivers/usb/dwc2/params.c
>> +++ b/drivers/usb/dwc2/params.c
>> @@ -76,6 +76,7 @@ static void dwc2_set_s3c6400_params(struct dwc2_hsotg *hsotg)
>> struct dwc2_core_params *p = &hsotg->params;
>>
>> p->power_down = DWC2_POWER_DOWN_PARAM_NONE;
>> + p->no_clock_gating = true;
>> p->phy_utmi_width = 8;
>> }
>>
>>
> In which mode host/device you see the issue?
I do my test in my device mode.
> What is your core version? Please provide GHWCFG1-4 registers values.
This is a result of dwc2_dump_global_registers() added just after
dwc2_lowlevel_hw_enable() in dwc2_driver_probe():
dwc2 12480000.hsotg: Core Global Registers
dwc2 12480000.hsotg: GOTGCTL @0xE0260000 : 0x000D0000
dwc2 12480000.hsotg: GOTGINT @0xE0260004 : 0x00000000
dwc2 12480000.hsotg: GAHBCFG @0xE0260008 : 0x00000027
dwc2 12480000.hsotg: GUSBCFG @0xE026000C : 0x0000540F
dwc2 12480000.hsotg: GRSTCTL @0xE0260010 : 0x80000040
dwc2 12480000.hsotg: GINTSTS @0xE0260014 : 0x54008428
dwc2 12480000.hsotg: GINTMSK @0xE0260018 : 0x800C3800
dwc2 12480000.hsotg: GRXSTSR @0xE026001C : 0x616EC77D
dwc2 12480000.hsotg: GRXFSIZ @0xE0260024 : 0x00000400
dwc2 12480000.hsotg: GNPTXFSIZ @0xE0260028 : 0x04000400
dwc2 12480000.hsotg: GNPTXSTS @0xE026002C : 0x00080400
dwc2 12480000.hsotg: GI2CCTL @0xE0260030 : 0x00000000
dwc2 12480000.hsotg: GPVNDCTL @0xE0260034 : 0x00000000
dwc2 12480000.hsotg: GGPIO @0xE0260038 : 0x00000000
dwc2 12480000.hsotg: GUID @0xE026003C : 0x00000000
dwc2 12480000.hsotg: GSNPSID @0xE0260040 : 0x4F54281A
dwc2 12480000.hsotg: GHWCFG1 @0xE0260044 : 0x00000000
dwc2 12480000.hsotg: GHWCFG2 @0xE0260048 : 0x228FFC50
dwc2 12480000.hsotg: GHWCFG3 @0xE026004C : 0x1E8084E8
dwc2 12480000.hsotg: GHWCFG4 @0xE0260050 : 0xFFF08030
dwc2 12480000.hsotg: GLPMCFG @0xE0260054 : 0x00000000
dwc2 12480000.hsotg: GPWRDN @0xE0260058 : 0x00000000
dwc2 12480000.hsotg: GDFIFOCFG @0xE026005C : 0x00000000
dwc2 12480000.hsotg: HPTXFSIZ @0xE0260100 : 0x00000000
dwc2 12480000.hsotg: PCGCTL @0xE0260E00 : 0x00000000
dwc2 12480000.hsotg: dwc2_check_params: Invalid parameter besl=1
dwc2 12480000.hsotg: dwc2_check_params: Invalid parameter
g_np_tx_fifo_size=1024
dwc2 12480000.hsotg: EPs: 16, dedicated fifos, 7808 entries in SPRAM
> Is the issue seen because of programming PCGCTL.PCGCTL_GATEHCLK bit
> only? To check it, could you please comment this bit setting/resetting
> in clock gating functions:
> dwc2_host_exit_clock_gating()
> dwc2_host_enter_clock_gating()
> dwc2_gadget_exit_clock_gating()
> dwc2_gadget_enter_clock_gating()
After removing programming PCGCTL.PCGCTL_GATEHCLK bit in the above
functions, everything works fine.
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
Powered by blists - more mailing lists