[PATCH 4/4] can: c_can: Add d_can suspend resume support
Marc Kleine-Budde
mkl at pengutronix.de
Tue Sep 4 03:27:18 EDT 2012
On 09/04/2012 08:14 AM, AnilKumar, Chimata wrote:
> Marc,
>
> Thanks for the comments,
>
> On Tue, Sep 04, 2012 at 01:31:35, Marc Kleine-Budde wrote:
>> On 09/03/2012 01:52 PM, AnilKumar Ch wrote:
>>> Adds suspend resume support to DCAN driver which enables
>>> DCAN power down mode bit (PDR). Then DCAN will ack the local
>>> power-down mode by setting PDA bit in STATUS register.
>>>
>>> Also adds a status flag to know the status of DCAN module,
>>> whether it is opened or not.
>>
>> Use "ndev->flags & IFF_UP" for that. Have a look at the at91_can driver
>> [1]. I'm not sure if you need locking here.
>>
>
> Then I can use this to check the status, lock is not
> required.
>
>> [1] http://lxr.free-electrons.com/source/drivers/net/can/at91_can.c#L1198
>>
>>> Signed-off-by: AnilKumar Ch <anilkumar at ti.com>
>>> ---
>>> drivers/net/can/c_can/c_can.c | 78 ++++++++++++++++++++++++++++++++
>>> drivers/net/can/c_can/c_can.h | 5 ++
>>> drivers/net/can/c_can/c_can_platform.c | 70 ++++++++++++++++++++++++++--
>>> 3 files changed, 150 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
>>> index c175410..36d5db4 100644
>>> --- a/drivers/net/can/c_can/c_can.c
>>> +++ b/drivers/net/can/c_can/c_can.c
>>> @@ -46,6 +46,9 @@
>>> #define IF_ENUM_REG_LEN 11
>>> #define C_CAN_IFACE(reg, iface) (C_CAN_IF1_##reg + (iface) * IF_ENUM_REG_LEN)
>>>
>>> +/* control extension register D_CAN specific */
>>> +#define CONTROL_EX_PDR BIT(8)
>>> +
>>> /* control register */
>>> #define CONTROL_TEST BIT(7)
>>> #define CONTROL_CCE BIT(6)
>>> @@ -65,6 +68,7 @@
>>> #define TEST_BASIC BIT(2)
>>>
>>> /* status register */
>>> +#define STATUS_PDA BIT(10)
>>> #define STATUS_BOFF BIT(7)
>>> #define STATUS_EWARN BIT(6)
>>> #define STATUS_EPASS BIT(5)
>>> @@ -164,6 +168,9 @@
>>> /* minimum timeout for checking BUSY status */
>>> #define MIN_TIMEOUT_VALUE 6
>>>
>>> +/* Wait for ~1 sec for INIT bit */
>>> +#define INIT_WAIT_COUNT 1000
>>
>> What unit? INIT_WAIT_MS would be a better name.
>>
>
> Sure, will change
>
>>> +
>>> /* napi related */
>>> #define C_CAN_NAPI_WEIGHT C_CAN_MSG_OBJ_RX_NUM
>>>
>>> @@ -1102,6 +1109,7 @@ static int c_can_open(struct net_device *dev)
>>>
>>> netif_start_queue(dev);
>>>
>>> + priv->is_opened = true;
>>> return 0;
>>>
>>> exit_irq_fail:
>>> @@ -1126,6 +1134,7 @@ static int c_can_close(struct net_device *dev)
>>> /* De-Initialize DCAN RAM */
>>> c_can_reset_ram(priv, false);
>>> c_can_pm_runtime_put_sync(priv);
>>> + priv->is_opened = false;
>>>
>>> return 0;
>>> }
>>> @@ -1154,6 +1163,75 @@ struct net_device *alloc_c_can_dev(void)
>>> }
>>> EXPORT_SYMBOL_GPL(alloc_c_can_dev);
>>>
>>> +#ifdef CONFIG_PM
>>> +int c_can_power_down(struct net_device *dev)
>>> +{
>>> + unsigned long time_out;
>>> + struct c_can_priv *priv = netdev_priv(dev);
>>> +
>>> + if (!priv->is_opened)
>>> + return 0;
>>
>> Should we add a BUG_ON(id->driver_data != BOSCH_D_CAN)?
>
> These APIs are called from platform driver where device type
> device type is verified. I think we have to add BUG_ON() in
> platform driver.
The platform driver returns if not on D_CAN and will not call this
function. But this functions are exported, so can be called by someone
else. So if the caller is not D_CAN, it's a bug.
>>> +
>>> + /* set `PDR` value so the device goes to power down mode */
>>> + priv->write_reg(priv, C_CAN_CTRL_EX_REG,
>>> + priv->read_reg(priv, C_CAN_CTRL_EX_REG) | CONTROL_EX_PDR);
>>
>> Please use an intermediate variable:
>>
>> u32 val;
>>
>> val = priv->read_reg(priv, C_CAN_CTRL_EX_REG);
>> val |= CONTROL_EX_PDR;
>> priv->write_reg(priv, C_CAN_CTRL_EX_REG, val);
>
> I will change
>
>>
>>> +
>>> + /* Wait for the PDA bit to get set */
>>> + time_out = jiffies + msecs_to_jiffies(INIT_WAIT_COUNT);
>>> + while (!(priv->read_reg(priv, C_CAN_STS_REG) & STATUS_PDA) &&
>>> + time_after(time_out, jiffies))
>>> + cpu_relax();
>>> +
>>> + if (time_after(jiffies, time_out))
>>> + return -ETIMEDOUT;
>>> +
>>> + c_can_stop(dev);
>>> +
>>> + /* De-initialize DCAN RAM */
>>> + c_can_reset_ram(priv, false);
>>> + c_can_pm_runtime_put_sync(priv);
>>> +
>>> + return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(c_can_power_down);
>>> +
>>> +int c_can_power_up(struct net_device *dev)
>>> +{
>>> + unsigned long time_out;
>>> + struct c_can_priv *priv = netdev_priv(dev);
>>> +
>>
>> BUG_ON?
>>
>>> + if (!priv->is_opened)
>>> + return 0;
>>> +
>>> + c_can_pm_runtime_get_sync(priv);
>>> + /* Initialize DCAN RAM */
>>> + c_can_reset_ram(priv, true);
>>> +
>>> + /* Clear PDR and INIT bits */
>>> + priv->write_reg(priv, C_CAN_CTRL_EX_REG,
>>> + priv->read_reg(priv, C_CAN_CTRL_EX_REG) & ~CONTROL_EX_PDR);
>>> + priv->write_reg(priv, C_CAN_CTRL_REG,
>>> + priv->read_reg(priv, C_CAN_CTRL_REG) & ~CONTROL_INIT);
>>> +
>>> + /* Wait for the PDA bit to get clear */
>>> + time_out = jiffies + msecs_to_jiffies(INIT_WAIT_COUNT);
>>> + while ((priv->read_reg(priv, C_CAN_STS_REG) & STATUS_PDA) &&
>>> + time_after(time_out, jiffies))
>>> + cpu_relax();
>>> +
>>> + if (time_after(jiffies, time_out))
>>> + return -ETIMEDOUT;
>>> +
>>> + c_can_start(dev);
>>> +
>>> + return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(c_can_power_up);
>>> +#else
>>> +#define c_can_power_down NULL
>>> +#define c_can_power_up NULL
>>
>> These are not used, are they?
>
> Not used, I will remove this else part and adding
> #ifdef CONFIG_PM in header file as well.
okay.
>>> +#endif
>>> +
>>> void free_c_can_dev(struct net_device *dev)
>>> {
>>> free_candev(dev);
>>> diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h
>>> index 5f6339c..e5dd7ef 100644
>>> --- a/drivers/net/can/c_can/c_can.h
>>> +++ b/drivers/net/can/c_can/c_can.h
>>> @@ -24,6 +24,7 @@
>>>
>>> enum reg {
>>> C_CAN_CTRL_REG = 0,
>>> + C_CAN_CTRL_EX_REG,
>>> C_CAN_STS_REG,
>>> C_CAN_ERR_CNT_REG,
>>> C_CAN_BTR_REG,
>>> @@ -104,6 +105,7 @@ static const u16 reg_map_c_can[] = {
>>>
>>> static const u16 reg_map_d_can[] = {
>>> [C_CAN_CTRL_REG] = 0x00,
>>> + [C_CAN_CTRL_EX_REG] = 0x02,
>>> [C_CAN_STS_REG] = 0x04,
>>> [C_CAN_ERR_CNT_REG] = 0x08,
>>> [C_CAN_BTR_REG] = 0x0C,
>>> @@ -166,6 +168,7 @@ struct c_can_priv {
>>> unsigned int tx_echo;
>>> void *priv; /* for board-specific data */
>>> u16 irqstatus;
>>> + bool is_opened;
>>> unsigned int instance;
>>> void (*ram_init) (unsigned int instance, bool enable);
>>> };
>>> @@ -174,5 +177,7 @@ struct net_device *alloc_c_can_dev(void);
>>> void free_c_can_dev(struct net_device *dev);
>>> int register_c_can_dev(struct net_device *dev);
>>> void unregister_c_can_dev(struct net_device *dev);
>>> +int c_can_power_up(struct net_device *dev);
>>> +int c_can_power_down(struct net_device *dev);
>>>
>>> #endif /* C_CAN_H */
>>> diff --git a/drivers/net/can/c_can/c_can_platform.c b/drivers/net/can/c_can/c_can_platform.c
>>> index c6963b2..65ec232 100644
>>> --- a/drivers/net/can/c_can/c_can_platform.c
>>> +++ b/drivers/net/can/c_can/c_can_platform.c
>>> @@ -255,15 +255,79 @@ static int __devexit c_can_plat_remove(struct platform_device *pdev)
>>> return 0;
>>> }
>>>
>>> +#ifdef CONFIG_PM
>>> +static int c_can_suspend(struct platform_device *pdev, pm_message_t state)
>>> +{
>>> + int ret;
>>> + struct net_device *ndev = platform_get_drvdata(pdev);
>>> + struct c_can_priv *priv = netdev_priv(ndev);
>>> + const struct platform_device_id *id = platform_get_device_id(pdev);
>>
>> Does that work on DT probed devices? You probably have to save the
>> id->driver_data in struct c_can_priv.
>
> I will add extra variable to c_can_priv to save the dev_id so
> that it will work for dt case as well.
>
>>
>>> +
>>> + if (id->driver_data != BOSCH_D_CAN) {
>>> + dev_warn(&pdev->dev, "Not supported\n");
>>> + return 0;
>>> + }
>>> +
>>> + if (netif_running(ndev)) {
>>> + netif_stop_queue(ndev);
>>> + netif_device_detach(ndev);
>>> + }
>>> +
>>> + ret = c_can_power_down(ndev);
>>> + if (ret) {
>>> + dev_err(&pdev->dev, "failed to enter power down mode\n");
>> netdev_err
>>> + return ret;
>>> + }
>>> +
>>> + priv->can.state = CAN_STATE_SLEEPING;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int c_can_resume(struct platform_device *pdev)
>>> +{
>>> + int ret;
>>> +
>> please remove the empty line ^^
>
> Sure
>
>>> + struct net_device *ndev = platform_get_drvdata(pdev);
>>> + struct c_can_priv *priv = netdev_priv(ndev);
>>> + const struct platform_device_id *id = platform_get_device_id(pdev);
>>> +
>>> + if (id->driver_data != BOSCH_D_CAN) {
>>> + dev_warn(&pdev->dev, "Not supported\n");
>>> + return 0;
>>> + }
>>> +
>>> + ret = c_can_power_up(ndev);
>>> + if (ret) {
>>> + dev_err(&pdev->dev, "Still in power down mode\n");
>>
>> netdev_err
>
> I will change.
>
>>
>>> + return ret;
>>> + }
>>> +
>>> + priv->can.state = CAN_STATE_ERROR_ACTIVE;
>>> +
>>> + if (netif_running(ndev)) {
>>> + netif_device_attach(ndev);
>>> + netif_start_queue(ndev);
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +#else
>>> +#define c_can_suspend NULL
>>> +#define c_can_resume NULL
>>> +#endif
>>> +
>>> static struct platform_driver c_can_plat_driver = {
>>> .driver = {
>>> .name = KBUILD_MODNAME,
>>> .owner = THIS_MODULE,
>>> .of_match_table = of_match_ptr(c_can_of_table),
>>> },
>>> - .probe = c_can_plat_probe,
>>> - .remove = __devexit_p(c_can_plat_remove),
>>> - .id_table = c_can_id_table,
>>> + .probe = c_can_plat_probe,
>>> + .remove = __devexit_p(c_can_plat_remove),
>>> + .suspend = c_can_suspend,
>>> + .resume = c_can_resume,
>>> + .id_table = c_can_id_table,
>>
>> Please don't indent here with tab. Just stay with one space on both
>> sides of the "=".
>>
>
> Point taken
>
> Thanks
> AnilKumar
>
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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