Re: [PATCH V2 1/2] can: flexcan: Add self wakeup support

From: Marc Kleine-Budde
Date: Tue Oct 30 2018 - 09:45:01 EST

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In reply to: Joakim Zhang: "[PATCH V2 1/2] can: flexcan: Add self wakeup support"
Next in thread: Joakim Zhang: "[PATCH V2 2/2] Documentation: can: flexcan: Add stop mode property to device tree"
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On 10/26/2018 11:00 AM, Joakim Zhang wrote:
> From: Dong Aisheng <aisheng.dong@xxxxxxx>
>
> If wakeup is enabled, enter stop mode, else enter disabled mode.
> Self wake can only work on stop mode.
>
> Starting from IMX6, the flexcan stop mode control bits is SoC specific,
> move it out of IP driver and parse it from devicetree.
>
> Signed-off-by: Dong Aisheng <aisheng.dong@xxxxxxx>
> Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
> ---
> drivers/net/can/flexcan.c | 141 +++++++++++++++++++++++++++++++++++---
> 1 file changed, 132 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> index 3813f6708201..d4708ba28c44 100644
> --- a/drivers/net/can/flexcan.c
> +++ b/drivers/net/can/flexcan.c
> @@ -19,12 +19,17 @@
> #include <linux/delay.h>
> #include <linux/interrupt.h>
> #include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/list.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/of_device.h>
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> #include <linux/regulator/consumer.h>
> +#include <linux/regmap.h>
>
> #define DRV_NAME "flexcan"
>
> @@ -132,7 +137,8 @@
> (FLEXCAN_ESR_ERR_BUS | FLEXCAN_ESR_ERR_STATE)
> #define FLEXCAN_ESR_ALL_INT \
> (FLEXCAN_ESR_TWRN_INT | FLEXCAN_ESR_RWRN_INT | \
> - FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT)
> + FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT | \
> + FLEXCAN_ESR_WAK_INT)
>
> /* FLEXCAN interrupt flag register (IFLAG) bits */
> /* Errata ERR005829 step7: Reserve first valid MB */
> @@ -255,6 +261,14 @@ struct flexcan_devtype_data {
> u32 quirks; /* quirks needed for different IP cores */
> };
>
> +struct flexcan_stop_mode {
> + struct regmap *gpr;
> + u8 req_gpr;
> + u8 req_bit;
> + u8 ack_gpr;
> + u8 ack_bit;
> +};
> +
> struct flexcan_priv {
> struct can_priv can;
> struct can_rx_offload offload;
> @@ -272,6 +286,7 @@ struct flexcan_priv {
> struct clk *clk_per;
> const struct flexcan_devtype_data *devtype_data;
> struct regulator *reg_xceiver;
> + struct flexcan_stop_mode stm;
>
> /* Read and Write APIs */
> u32 (*read)(void __iomem *addr);
> @@ -392,6 +407,22 @@ static void flexcan_clks_disable(const struct flexcan_priv *priv)
> clk_disable_unprepare(priv->clk_per);
> }
>
> +static inline void flexcan_enter_stop_mode(struct flexcan_priv *priv)
> +{
> + /* enable stop request */
> + if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP)

Why do you check the quirk here? This should only be called if the
device is wakeup capable.

> + regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
> + 1 << priv->stm.req_bit, 1 << priv->stm.req_bit);

Please align with the opening bracket of "regmap_update_bits(".

> +}
> +
> +static inline void flexcan_exit_stop_mode(struct flexcan_priv *priv)
> +{
> + /* remove stop request */
> + if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP)

same here

> + regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
> + 1 << priv->stm.req_bit, 0);

same here

> +}
> +
> static inline int flexcan_transceiver_enable(const struct flexcan_priv *priv)
> {
> if (!priv->reg_xceiver)
> @@ -955,6 +986,10 @@ static int flexcan_chip_start(struct net_device *dev)
> reg_mcr |= FLEXCAN_MCR_FEN |
> FLEXCAN_MCR_MAXMB(priv->tx_mb_idx);
> }
> +
> + /* enable self wakeup */
> + reg_mcr |= FLEXCAN_MCR_WAK_MSK | FLEXCAN_MCR_SLF_WAK;
> +
> netdev_dbg(dev, "%s: writing mcr=0x%08x", __func__, reg_mcr);
> priv->write(reg_mcr, &regs->mcr);
>
> @@ -1240,6 +1275,56 @@ static void unregister_flexcandev(struct net_device *dev)
> unregister_candev(dev);
> }
>
> +static int flexcan_of_parse_stop_mode(struct platform_device *pdev)
> +{
> + struct net_device *dev = platform_get_drvdata(pdev);
> + struct device_node *np = pdev->dev.of_node;
> + struct device_node *node;
> + struct flexcan_priv *priv;
> + phandle phandle;
> + u32 out_val[5];
> + int ret;
> +
> + if (!np)
> + return -EINVAL;
> +
> + /* stop mode property format is:
> + * <&gpr req_gpr req_bit ack_gpr ack_bit>.
> + */
> + ret = of_property_read_u32_array(np, "fsl,stop-mode", out_val, 5);
> + if (ret) {
> + dev_dbg(&pdev->dev, "no stop-mode property\n");
> + return ret;
> + }
> + phandle = *out_val;
> +
> + node = of_find_node_by_phandle(phandle);
> + if (!node) {
> + dev_dbg(&pdev->dev, "could not find gpr node by phandle\n");
> + return PTR_ERR(node);
> + }
> +
> + priv = netdev_priv(dev);
> + priv->stm.gpr = syscon_node_to_regmap(node);
> + if (IS_ERR(priv->stm.gpr)) {
> + dev_dbg(&pdev->dev, "could not find gpr regmap\n");
> + return PTR_ERR(priv->stm.gpr);
> + }
> +
> + of_node_put(node);
> +
> + priv->stm.req_gpr = out_val[1];
> + priv->stm.req_bit = out_val[2];
> + priv->stm.ack_gpr = out_val[3];
> + priv->stm.ack_bit = out_val[4];
> +
> + dev_dbg(&pdev->dev, "gpr %s req_gpr 0x%x req_bit %u ack_gpr 0x%x ack_bit %u\n",
> + node->full_name, priv->stm.req_gpr,
> + priv->stm.req_bit, priv->stm.ack_gpr,
> + priv->stm.ack_bit);
> + return 0;
> +}
> +
> static const struct of_device_id flexcan_of_match[] = {
> { .compatible = "fsl,imx6q-flexcan", .data = &fsl_imx6q_devtype_data, },
> { .compatible = "fsl,imx28-flexcan", .data = &fsl_imx28_devtype_data, },
> @@ -1271,6 +1356,7 @@ static int flexcan_probe(struct platform_device *pdev)
> struct flexcan_regs __iomem *regs;
> int err, irq;
> u32 clock_freq = 0;
> + int wakeup = 1;

Make it a bool.
Why is is default enabled?
See below.

>
> reg_xceiver = devm_regulator_get(&pdev->dev, "xceiver");
> if (PTR_ERR(reg_xceiver) == -EPROBE_DEFER)
> @@ -1400,6 +1486,16 @@ static int flexcan_probe(struct platform_device *pdev)
>
> devm_can_led_init(dev);
>
> + if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {

Please add another QUIRK.

> + err = flexcan_of_parse_stop_mode(pdev);
> + if (err) {
> + wakeup = 0;
> + dev_dbg(&pdev->dev, "failed to parse stop-mode\n");
> + }
> + }
> +
> + device_set_wakeup_capable(&pdev->dev, wakeup);

What about moving this into "flexcan_of_parse_stop_mode(pdev);", and
rename this function into ..._setup_stop_mode() or something similar.

> +
> pm_runtime_put(&pdev->dev);
>
> dev_info(&pdev->dev, "device registered (reg_base=%p, irq=%d)\n",
> @@ -1437,10 +1533,18 @@ static int __maybe_unused flexcan_suspend(struct device *device)
> int err = 0;
>
> if (netif_running(dev)) {
> - err = flexcan_chip_disable(priv);
> - if (err)
> - return err;
> - err = pm_runtime_force_suspend(device);
> + /* if wakeup is enabled, enter stop mode
> + * else enter disabled mode.
> + */
> + if (device_may_wakeup(device)) {
> + enable_irq_wake(dev->irq);
> + flexcan_enter_stop_mode(priv);
> + } else {
> + err = flexcan_chip_disable(priv);
> + if (err)
> + return err;
> + err = pm_runtime_force_suspend(device);
> + }
>
> netif_stop_queue(dev);
> netif_device_detach(dev);
> @@ -1461,10 +1565,12 @@ static int __maybe_unused flexcan_resume(struct device *device)
> netif_device_attach(dev);
> netif_start_queue(dev);
>
> - err = pm_runtime_force_resume(device);
> - if (err)
> - return err;
> - err = flexcan_chip_enable(priv);
> + if (!device_may_wakeup(device)) {
> + err = pm_runtime_force_resume(device);
> + if (err)
> + return err;
> + err = flexcan_chip_enable(priv);
> + }
> }
> return err;
> }
> @@ -1489,10 +1595,27 @@ static int __maybe_unused flexcan_runtime_resume(struct device *device)
> return 0;
> }
>
> +static int __maybe_unused flexcan_noirq_resume(struct device *device)
> +{
> + struct net_device *dev = dev_get_drvdata(device);
> + struct flexcan_priv *priv = netdev_priv(dev);
> +
> + /* exit stop mode during noirq stage avoid continuously entering
> + * wakeup ISR before CAN resume back.
> + */
> + if (netif_running(dev) && device_may_wakeup(device)) {
> + disable_irq_wake(dev->irq);
> + flexcan_exit_stop_mode(priv);
> + }
> +
> + return 0;
> +}
> +
> static const struct dev_pm_ops flexcan_pm_ops = {
> SET_SYSTEM_SLEEP_PM_OPS(flexcan_suspend, flexcan_resume)
> SET_RUNTIME_PM_OPS(flexcan_runtime_suspend, flexcan_runtime_resume,
> NULL)
> + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(NULL, flexcan_noirq_resume)
> };
>
> static struct platform_driver flexcan_driver = {
>

Marc

--
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Next message: Vasily Averin: "Re: [PATCH 3/7] ext4 resize: missing brelse() in case success in add_new_gdb()"
Previous message: Jianxin Pan: "Re: [PATCH v5 3/3] clk: meson: add sub MMC clock controller driver"
In reply to: Joakim Zhang: "[PATCH V2 1/2] can: flexcan: Add self wakeup support"
Next in thread: Joakim Zhang: "[PATCH V2 2/2] Documentation: can: flexcan: Add stop mode property to device tree"
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