linux-kernel - Re: [PATCH v4] usb: ohci-at91: Forcibly suspend ports while USB suspend

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
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <57695F33.5080306@atmel.com>
Date:	Tue, 21 Jun 2016 17:37:23 +0200
From:	Nicolas Ferre <nicolas.ferre@...el.com>
To:	Wenyou Yang <wenyou.yang@...el.com>,
	Alan Stern <stern@...land.harvard.edu>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>
CC:	<linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-usb@...r.kernel.org>
Subject: Re: [PATCH v4] usb: ohci-at91: Forcibly suspend ports while USB
 suspend

Le 21/06/2016 03:32, Wenyou Yang a écrit :
> In order to save power consumption, as a workaround, forcibly suspend
> the USB PORTA/B/C via setting the SUSPEND_A/B/C bits of OHCI Interrupt
> Configuration Register in the SFR while OHCI USB suspend.
> 
> This suspend operation must be done before the USB clock is disabled,
> resume after the USB clock is enabled.
> 
> Signed-off-by: Wenyou Yang <wenyou.yang@...el.com>

Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>

Alan, can you take it as it doesn't have dependency on the at91 material
anymore.

Thanks, bye.

> ---
> 
> Changes in v4:
>  - To check whether the SFR node with "atmel,sama5d2-sfr" compatible
>    is present or not to decide if this feature is applied or not
>    when USB OHCI suspend/resume, instead of new compatible.
>  - Drop the compatible "atmel,sama5d2-ohci".
>  - Drop [PATCH 2/2] ARM: at91/dt: sama5d2: Use new compatible for
>    ohci node.
>  - Drop include/soc/at91/at91_sfr.h, move the macro definitions to
>    atmel-sfr.h which already exists.
>  - Change the defines to align the exists.
> 
> Changes in v3:
>  - Change the compatible description for more precise.
> 
> Changes in v2:
>  - Add compatible to support forcibly suspend the ports.
>  - Add soc/at91/at91_sfr.h to accommodate the defines.
>  - Add error checking for .sfr_regmap.
>  - Remove unnecessary regmap_read() statement.
> 
>  drivers/usb/host/ohci-at91.c | 55 ++++++++++++++++++++++++++++++++++++++++++++
>  include/soc/at91/atmel-sfr.h | 13 +++++++++++
>  2 files changed, 68 insertions(+)
> 
> diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
> index d177372..f07c398 100644
> --- a/drivers/usb/host/ohci-at91.c
> +++ b/drivers/usb/host/ohci-at91.c
> @@ -21,8 +21,11 @@
>  #include <linux/io.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
>  #include <linux/usb.h>
>  #include <linux/usb/hcd.h>
> +#include <soc/at91/atmel-sfr.h>
>  
>  #include "ohci.h"
>  
> @@ -51,6 +54,7 @@ struct ohci_at91_priv {
>  	struct clk *hclk;
>  	bool clocked;
>  	bool wakeup;		/* Saved wake-up state for resume */
> +	struct regmap *sfr_regmap;
>  };
>  /* interface and function clocks; sometimes also an AHB clock */
>  
> @@ -132,6 +136,17 @@ static void at91_stop_hc(struct platform_device *pdev)
>  
>  /*-------------------------------------------------------------------------*/
>  
> +struct regmap *at91_dt_syscon_sfr(void)
> +{
> +	struct regmap *regmap;
> +
> +	regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-sfr");
> +	if (IS_ERR(regmap))
> +		regmap = NULL;
> +
> +	return regmap;
> +}
> +
>  static void usb_hcd_at91_remove (struct usb_hcd *, struct platform_device *);
>  
>  /* configure so an HC device and id are always provided */
> @@ -197,6 +212,10 @@ static int usb_hcd_at91_probe(const struct hc_driver *driver,
>  		goto err;
>  	}
>  
> +	ohci_at91->sfr_regmap = at91_dt_syscon_sfr();
> +	if (!ohci_at91->sfr_regmap)
> +		dev_warn(dev, "failed to find sfr node\n");
> +
>  	board = hcd->self.controller->platform_data;
>  	ohci = hcd_to_ohci(hcd);
>  	ohci->num_ports = board->ports;
> @@ -581,6 +600,38 @@ static int ohci_hcd_at91_drv_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static int ohci_at91_port_ctrl(struct regmap *regmap, bool enable)
> +{
> +	u32 regval;
> +	int ret;
> +
> +	if (!regmap)
> +		return 0;
> +
> +	ret = regmap_read(regmap, AT91_SFR_OHCIICR, &regval);
> +	if (ret)
> +		return ret;
> +
> +	if (enable)
> +		regval &= ~AT91_OHCIICR_USB_SUSPEND;
> +	else
> +		regval |= AT91_OHCIICR_USB_SUSPEND;
> +
> +	regmap_write(regmap, AT91_SFR_OHCIICR, regval);
> +
> +	return 0;
> +}
> +
> +static int ohci_at91_port_suspend(struct regmap *regmap)
> +{
> +	return ohci_at91_port_ctrl(regmap, false);
> +}
> +
> +static int ohci_at91_port_resume(struct regmap *regmap)
> +{
> +	return ohci_at91_port_ctrl(regmap, true);
> +}
> +
>  static int __maybe_unused
>  ohci_hcd_at91_drv_suspend(struct device *dev)
>  {
> @@ -618,6 +669,8 @@ ohci_hcd_at91_drv_suspend(struct device *dev)
>  		ohci_writel(ohci, ohci->hc_control, &ohci->regs->control);
>  		ohci->rh_state = OHCI_RH_HALTED;
>  
> +		ohci_at91_port_suspend(ohci_at91->sfr_regmap);
> +
>  		/* flush the writes */
>  		(void) ohci_readl (ohci, &ohci->regs->control);
>  		at91_stop_clock(ohci_at91);
> @@ -637,6 +690,8 @@ ohci_hcd_at91_drv_resume(struct device *dev)
>  
>  	at91_start_clock(ohci_at91);
>  
> +	ohci_at91_port_resume(ohci_at91->sfr_regmap);
> +
>  	ohci_resume(hcd, false);
>  	return 0;
>  }
> diff --git a/include/soc/at91/atmel-sfr.h b/include/soc/at91/atmel-sfr.h
> index 2f9bb98..cca28d4 100644
> --- a/include/soc/at91/atmel-sfr.h
> +++ b/include/soc/at91/atmel-sfr.h
> @@ -13,6 +13,19 @@
>  #ifndef _LINUX_MFD_SYSCON_ATMEL_SFR_H
>  #define _LINUX_MFD_SYSCON_ATMEL_SFR_H
>  
> +#define AT91_SFR_DDRCFG		0x04	/* DDR Configuration Register */
> +/* 0x08 ~ 0x0c: Reserved */
> +#define AT91_SFR_OHCIICR	0x10	/* OHCI Interrupt Configuration Register */
> +#define AT91_SFR_OHCIISR	0x14	/* OHCI Interrupt Status Register */
>  #define AT91_SFR_I2SCLKSEL	0x90	/* I2SC Register */
>  
> +/* Field definitions */
> +#define AT91_OHCIICR_SUSPEND_A	BIT(8)
> +#define AT91_OHCIICR_SUSPEND_B	BIT(9)
> +#define AT91_OHCIICR_SUSPEND_C	BIT(10)
> +
> +#define AT91_OHCIICR_USB_SUSPEND	(AT91_OHCIICR_SUSPEND_A | \
> +					 AT91_OHCIICR_SUSPEND_B | \
> +					 AT91_OHCIICR_SUSPEND_C)
> +
>  #endif /* _LINUX_MFD_SYSCON_ATMEL_SFR_H */
> 


-- 
Nicolas Ferre