Re: [PATCH 5/7] usb: misc: add driver for Intel drcfg controlled port mux

[Lu Baolu]

On 03/04/2016 09:44 AM, Greg Kroah-Hartman wrote:
> On Fri, Mar 04, 2016 at 09:38:58AM +0800, Lu Baolu wrote:
>>
>> On 03/04/2016 12:14 AM, Greg Kroah-Hartman wrote:
>>> On Thu, Mar 03, 2016 at 02:37:42PM +0800, Lu Baolu wrote:
>>>> Several Intel PCHs and SOCs have an internal mux that is used to
>>>> share one USB port between device controller and host controller.
>>>> The mux is handled through the Dual Role Configuration Register.
>>>>
>>>> Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
>>>> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
>>>> Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
>>>> Reviewed-by: Felipe Balbi <balbi@xxxxxxxxxx>
>>>> ---
>>>>  MAINTAINERS                        |   1 +
>>>>  drivers/usb/misc/Kconfig           |   7 ++
>>>>  drivers/usb/misc/Makefile          |   1 +
>>>>  drivers/usb/misc/intel-mux-drcfg.c | 174 +++++++++++++++++++++++++++++++++++++
>>>>  4 files changed, 183 insertions(+)
>>>>  create mode 100644 drivers/usb/misc/intel-mux-drcfg.c
>>>>
>>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>>> index 0f321e4..20eb873 100644
>>>> --- a/MAINTAINERS
>>>> +++ b/MAINTAINERS
>>>> @@ -11396,6 +11396,7 @@ S:	Supported
>>>>  F:	drivers/usb/misc/mux.c
>>>>  F:	include/linux/usb/mux.h
>>>>  F:	drivers/usb/misc/intel-mux-gpio.c
>>>> +F:	drivers/usb/misc/intel-mux-drcfg.c
>>>>  
>>>>  USB PRINTER DRIVER (usblp)
>>>>  M:	Pete Zaitcev <zaitcev@xxxxxxxxxx>
>>>> diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
>>>> index 33e6386..befd910 100644
>>>> --- a/drivers/usb/misc/Kconfig
>>>> +++ b/drivers/usb/misc/Kconfig
>>>> @@ -281,3 +281,10 @@ config INTEL_MUX_GPIO
>>>>  	help
>>>>  	  Say Y here to enable support for Intel dual role port mux
>>>>  	  controlled by GPIOs.
>>>> +
>>>> +config INTEL_MUX_DRCFG
>>>> +	tristate "Intel dual role port mux controlled by register"
>>>> +	select USB_MUX
>>>> +	help
>>>> +	  Say Y here to enable support for Intel dual role port mux
>>>> +	  controlled by the Dual Role Configuration Registers.
>>>> diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile
>>>> index da4fb4e..c4d19a0 100644
>>>> --- a/drivers/usb/misc/Makefile
>>>> +++ b/drivers/usb/misc/Makefile
>>>> @@ -32,3 +32,4 @@ obj-$(CONFIG_USB_LINK_LAYER_TEST)	+= lvstest.o
>>>>  
>>>>  obj-$(CONFIG_USB_MUX)			+= mux.o
>>>>  obj-$(CONFIG_INTEL_MUX_GPIO)		+= intel-mux-gpio.o
>>>> +obj-$(CONFIG_INTEL_MUX_DRCFG)		+= intel-mux-drcfg.o
>>>> diff --git a/drivers/usb/misc/intel-mux-drcfg.c b/drivers/usb/misc/intel-mux-drcfg.c
>>>> new file mode 100644
>>>> index 0000000..29081c5
>>>> --- /dev/null
>>>> +++ b/drivers/usb/misc/intel-mux-drcfg.c
>>>> @@ -0,0 +1,174 @@
>>>> +/**
>>>> + * intel-mux-drcfg.c - Driver for Intel USB mux via register
>>>> + *
>>>> + * Copyright (C) 2016 Intel Corporation
>>>> + * Author: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
>>>> + * Author: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
>>>> + *
>>>> + * This program is free software; you can redistribute it and/or modify
>>>> + * it under the terms of the GNU General Public License version 2 as
>>>> + * published by the Free Software Foundation.
>>>> + */
>>>> +
>>>> +#include <linux/slab.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/property.h>
>>>> +#include <linux/usb/mux.h>
>>>> +#include <linux/platform_device.h>
>>>> +
>>>> +#define INTEL_MUX_CFG0		0x00
>>>> +#define INTEL_MUX_CFG1		0x04
>>>> +#define CFG0_SW_IDPIN		BIT(20)
>>>> +#define CFG0_SW_IDPIN_EN	BIT(21)
>>>> +#define CFG0_SW_VBUS_VALID	BIT(24)
>>>> +#define CFG1_SW_MODE		BIT(29)
>>>> +#define CFG1_POLL_TIMEOUT	1000
>>>> +
>>>> +struct intel_usb_mux {
>>>> +	struct usb_mux_dev umdev;
>>>> +	void __iomem *regs;
>>>> +	u32 cfg0_ctx;
>>>> +};
>>>> +
>>>> +static inline int intel_mux_drcfg_switch(struct usb_mux_dev *umdev, bool host)
>>>> +{
>>>> +	struct intel_usb_mux *mux;
>>>> +	unsigned long timeout;
>>>> +	u32 data;
>>>> +
>>>> +	mux = container_of(umdev, struct intel_usb_mux, umdev);
>>>> +
>>>> +	/* Check and set mux to SW controlled mode */
>>>> +	data = readl(mux->regs + INTEL_MUX_CFG0);
>>>> +	if (!(data & CFG0_SW_IDPIN_EN)) {
>>>> +		data |= CFG0_SW_IDPIN_EN;
>>>> +		writel(data, mux->regs + INTEL_MUX_CFG0);
>>>> +	}
>>>> +
>>>> +	/*
>>>> +	 * Configure CFG0 to switch the mux and VBUS_VALID bit is
>>>> +	 * required for device mode.
>>>> +	 */
>>>> +	data = readl(mux->regs + INTEL_MUX_CFG0);
>>>> +	if (host)
>>>> +		data &= ~(CFG0_SW_IDPIN | CFG0_SW_VBUS_VALID);
>>>> +	else
>>>> +		data |= (CFG0_SW_IDPIN | CFG0_SW_VBUS_VALID);
>>>> +	writel(data, mux->regs + INTEL_MUX_CFG0);
>>>> +
>>>> +	/*
>>>> +	 * Polling CFG1 for safety, most case it takes about 600ms
>>>> +	 * to finish mode switching, set TIMEOUT long enough.
>>>> +	 */
>>>> +	timeout = jiffies + msecs_to_jiffies(CFG1_POLL_TIMEOUT);
>>>> +
>>>> +	/* Polling on CFG1 register to confirm mode switch. */
>>>> +	while (!time_after(jiffies, timeout)) {
>>>> +		data = readl(mux->regs + INTEL_MUX_CFG1);
>>>> +		if (!(host ^ (data & CFG1_SW_MODE)))
>>>> +			return 0;
>>>> +		/* interval for polling is set to about 5ms */
>>>> +		usleep_range(5000, 5100);
>>>> +	}
>>>> +
>>>> +	return -ETIMEDOUT;
>>>> +}
>>>> +
>>>> +static int intel_mux_drcfg_cable_set(struct usb_mux_dev *umdev)
>>>> +{
>>>> +	dev_dbg(umdev->dev, "drcfg mux switch to HOST\n");
>>>> +
>>>> +	return intel_mux_drcfg_switch(umdev, true);
>>>> +}
>>>> +
>>>> +static int intel_mux_drcfg_cable_unset(struct usb_mux_dev *umdev)
>>>> +{
>>>> +	dev_dbg(umdev->dev, "drcfg mux switch to DEVICE\n");
>>>> +
>>>> +	return intel_mux_drcfg_switch(umdev, false);
>>>> +}
>>>> +
>>>> +static int intel_mux_drcfg_probe(struct platform_device *pdev)
>>>> +{
>>>> +	struct intel_usb_mux *mux;
>>>> +	struct usb_mux_dev *umdev;
>>>> +	struct device *dev = &pdev->dev;
>>>> +	u64 start, size;
>>>> +	int ret;
>>>> +
>>>> +	mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
>>>> +	if (!mux)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	ret = device_property_read_u64(dev, "reg-start", &start);
>>>> +	ret |= device_property_read_u64(dev, "reg-size", &size);
>>>> +	if (ret)
>>>> +		return -ENODEV;
>>> And you leaked memory :(
>> Did you mean device_property_read_*() allocated memory
>> and I need to release it before return error?
>>
>>>> +
>>>> +	mux->regs = devm_ioremap_nocache(dev, start, size);
>>>> +	if (!mux->regs)
>>>> +		return -ENOMEM;
>>> Memory gone :(
>> devm interface will manage the resources by itself, or not?
> Ugh, you are right, nevermind, these both are fine, sorry for the noise.
>
>>>> +	mux->cfg0_ctx = readl(mux->regs + INTEL_MUX_CFG0);
>>>> +
>>>> +	umdev = &mux->umdev;
>>>> +	umdev->dev = dev;
>>>> +	umdev->cable_name = "USB-HOST";
>>>> +	umdev->cable_set_cb = intel_mux_drcfg_cable_set;
>>>> +	umdev->cable_unset_cb = intel_mux_drcfg_cable_unset;
>>>> +
>>>> +	ret = usb_mux_register(umdev);
>>>> +	if (ret)
>>>> +		writel(mux->cfg0_ctx, mux->regs + INTEL_MUX_CFG0);
>>> So if an error happens you just keep going?
>> No. If error happens, I will restore the register and return error.
> That seems a bit "odd", and will change when you fix up the api...

Sure.

>
> thanks,
>
> greg k-h
>

Thank you for your time.

Best Regards,
baolu