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Date: Mon, 2 Dec 2013 11:39:03 +0200
From: Roger Quadros <rogerq@...com>
To: Michael Trimarchi <michael@...rulasolutions.com>
CC: Lee Jones <lee.jones@...aro.org>, <sameo@...ux.intel.com>,
<tomi.valkeinen@...com>, Felipe Balbi <balbi@...com>,
Stefan Roese <sr@...x.de>, <ljkenny.mailinglists@...il.com>,
Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
USB list <linux-usb@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <stable@...r.kernel.org>,
Benoit Cousson <bcousson@...libre.com>,
"tony@...mide.com" <tony@...mide.com>,
Paul Walmsley <paul@...an.com>
Subject: Re: [PATCH 1/1] mfd: omap-usb-host: Fix USB device detection problems
on OMAP4 Panda
+Benoit, Tony, Paul.
Hi Michael,
On 11/30/2013 06:48 AM, Michael Trimarchi wrote:
> Hi Roger
>
> On Fri, Nov 29, 2013 at 2:01 PM, Roger Quadros <rogerq@...com> wrote:
>> With u-boot 2013.10, USB devices are sometimes not detected
>> on OMAP4 Panda. To make us independent of what bootloader does
>> with the USB Host module, we must RESET it to get it to a known
>> good state. This patch Soft RESETs the USB Host module.
>>
>> Reported-by: Tomi Valkeinen <tomi.valkeinen@...com>
>> Cc: <stable@...r.kernel.org> # 3.10+
>> Signed-off-by: Roger Quadros <rogerq@...com>
>> ---
>> drivers/mfd/omap-usb-host.c | 115 +++++++++++++++++++++++++++++++++++++++++---
>> 1 file changed, 109 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/mfd/omap-usb-host.c b/drivers/mfd/omap-usb-host.c
>> index 142650f..d4bd464 100644
>> --- a/drivers/mfd/omap-usb-host.c
>> +++ b/drivers/mfd/omap-usb-host.c
>> @@ -43,14 +43,18 @@
>> /* UHH Register Set */
>> #define OMAP_UHH_REVISION (0x00)
>> #define OMAP_UHH_SYSCONFIG (0x10)
>> -#define OMAP_UHH_SYSCONFIG_MIDLEMODE (1 << 12)
>> +#define OMAP_UHH_SYSCONFIG_MIDLEMASK (3 << 12)
>> +#define OMAP_UHH_SYSCONFIG_MIDLESHIFT (12)
>> #define OMAP_UHH_SYSCONFIG_CACTIVITY (1 << 8)
>> -#define OMAP_UHH_SYSCONFIG_SIDLEMODE (1 << 3)
>> +#define OMAP_UHH_SYSCONFIG_SIDLEMASK (3 << 3)
>> +#define OMAP_UHH_SYSCONFIG_SIDLESHIFT (3)
>> #define OMAP_UHH_SYSCONFIG_ENAWAKEUP (1 << 2)
>> #define OMAP_UHH_SYSCONFIG_SOFTRESET (1 << 1)
>> #define OMAP_UHH_SYSCONFIG_AUTOIDLE (1 << 0)
>>
>> #define OMAP_UHH_SYSSTATUS (0x14)
>> +#define OMAP_UHH_SYSSTATUS_RESETDONE (1 << 0)
>> +
>> #define OMAP_UHH_HOSTCONFIG (0x40)
>> #define OMAP_UHH_HOSTCONFIG_ULPI_BYPASS (1 << 0)
>> #define OMAP_UHH_HOSTCONFIG_ULPI_P1_BYPASS (1 << 0)
>> @@ -66,10 +70,10 @@
>> #define OMAP4_UHH_HOSTCONFIG_APP_START_CLK (1 << 31)
>>
>> /* OMAP4-specific defines */
>> -#define OMAP4_UHH_SYSCONFIG_IDLEMODE_CLEAR (3 << 2)
>> -#define OMAP4_UHH_SYSCONFIG_NOIDLE (1 << 2)
>> -#define OMAP4_UHH_SYSCONFIG_STDBYMODE_CLEAR (3 << 4)
>> -#define OMAP4_UHH_SYSCONFIG_NOSTDBY (1 << 4)
>> +#define OMAP4_UHH_SYSCONFIG_MIDLEMASK (3 << 2)
>> +#define OMAP4_UHH_SYSCONFIG_MIDLESHIFT (2)
>> +#define OMAP4_UHH_SYSCONFIG_SIDLEMASK (3 << 4)
>> +#define OMAP4_UHH_SYSCONFIG_SIDLESHIFT (4)
>> #define OMAP4_UHH_SYSCONFIG_SOFTRESET (1 << 0)
>>
>> #define OMAP4_P1_MODE_CLEAR (3 << 16)
>> @@ -81,6 +85,12 @@
>>
>> #define OMAP_UHH_DEBUG_CSR (0x44)
>>
>> +/* MIDLE modes */
>> +#define OMAP_UHH_SYSCONFIG_MIDLE_NOSTANDBY (1)
>> +
>> +/* SIDLE modes */
>> +#define OMAP_UHH_SYSCONFIG_SIDLE_NOIDLE (1)
>> +
>> /* Values of UHH_REVISION - Note: these are not given in the TRM */
>> #define OMAP_USBHS_REV1 0x00000010 /* OMAP3 */
>> #define OMAP_USBHS_REV2 0x50700100 /* OMAP4 */
>> @@ -474,6 +484,97 @@ static unsigned omap_usbhs_rev2_hostconfig(struct usbhs_hcd_omap *omap,
>> return reg;
>> }
>>
>
> I'm digging in the code but as I understand this should be done by
> omap_hwmod and
> i660 avoid reset of the ehci module. This is done by ocp_softreset?
>
It won't be done by omap_hwmod as we set HWMOD_INIT_NO_RESET flag in the hwmod data [1].
Question is do we do it in the driver of leave it to hwmod?
The other concern about i660 is in this comment [1]
/*
* During system boot; If the hwmod framework resets the module
* the module will have smart idle settings; which can lead to deadlock
* (above Errata Id:i660); so, dont reset the module during boot;
* Use HWMOD_INIT_NO_RESET.
*/
But if you look at the errata document [2], Advisory 1.108, it doesn't say that we can't be in smart-idle, but
only that we should put the module in force-idle, before cutting the module's functional clock. It also states
that the only way to recover from a lockup condition is to soft reset the module. So I'm not sure if the above comment
in the code is really valid. What if the lockup happens in the bootloader? In that case we will have to reset the module in
the kernel.
Doing the reset in probe does solve a problem for now i.e. eliminates dependency on bootloader.
[1] - http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c#n2024
[2] - http://www.ti.com/litv/pdf/sprz318e
>
>> +static void omap_usbhs_rev1_reset(struct device *dev)
>> +{
>> + struct usbhs_hcd_omap *omap = dev_get_drvdata(dev);
>> + u32 reg;
>> + unsigned long timeout;
>> +
>> + reg = usbhs_read(omap->uhh_base, OMAP_UHH_SYSCONFIG);
>> +
>> + /* Soft Reset */
>> + usbhs_write(omap->uhh_base, OMAP_UHH_SYSCONFIG,
>> + reg | OMAP_UHH_SYSCONFIG_SOFTRESET);
>> +
>> + timeout = jiffies + msecs_to_jiffies(100);
>> + while (!(usbhs_read(omap->uhh_base, OMAP_UHH_SYSSTATUS)
>> + & OMAP_UHH_SYSSTATUS_RESETDONE)) {
>> + cpu_relax();
>> +
>> + if (time_after(jiffies, timeout)) {
>> + dev_err(dev, "Soft RESET operation timed out\n");
>> + break;
>> + }
>> + }
>> +
>> + /* Set No-Standby */
>> + reg &= ~OMAP_UHH_SYSCONFIG_MIDLEMASK;
>> + reg |= OMAP_UHH_SYSCONFIG_MIDLE_NOSTANDBY
>> + << OMAP_UHH_SYSCONFIG_MIDLESHIFT;
>> +
>> + /* Set No-Idle */
>> + reg &= ~OMAP_UHH_SYSCONFIG_SIDLEMASK;
>> + reg |= OMAP_UHH_SYSCONFIG_SIDLE_NOIDLE
>> + << OMAP_UHH_SYSCONFIG_SIDLESHIFT;
>> +
>> + usbhs_write(omap->uhh_base, OMAP_UHH_SYSCONFIG, reg);
>> +}
>> +
>> +static void omap_usbhs_rev2_reset(struct device *dev)
>> +{
>> + struct usbhs_hcd_omap *omap = dev_get_drvdata(dev);
>> + u32 reg;
>> + unsigned long timeout;
>> +
>> + reg = usbhs_read(omap->uhh_base, OMAP_UHH_SYSCONFIG);
>> +
>> + /* Soft Reset */
>> + usbhs_write(omap->uhh_base, OMAP_UHH_SYSCONFIG,
>> + reg | OMAP4_UHH_SYSCONFIG_SOFTRESET);
>> +
>> + /* OMAP4: Need to wait before SYSCONFIG can be accessed */
>> + udelay(2);
>
> is this the srst_udelay?
It was supposed to be, but it doesn't seem to be necessary for the UHH module. So I'll get rid of that.
cheers,
-roger
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