diff mbox series

[v7,04/10] mhi: pci_generic: Add support for reset

Message ID 1609768179-10132-5-git-send-email-loic.poulain@linaro.org
State Superseded
Headers show
Series mhi: pci_generic: Misc improvements | expand

Commit Message

Loic Poulain Jan. 4, 2021, 1:49 p.m. UTC 
Add support for resetting the device, reset can be triggered in case
of error or manually via sysfs (/sys/bus/pci/devices/*/reset).

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>

---
 drivers/bus/mhi/pci_generic.c | 121 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 108 insertions(+), 13 deletions(-)

-- 
2.7.4

Comments

Manivannan Sadhasivam Jan. 4, 2021, 3:21 p.m. UTC | #1 
On Mon, Jan 04, 2021 at 02:49:33PM +0100, Loic Poulain wrote:
> Add support for resetting the device, reset can be triggered in case

> of error or manually via sysfs (/sys/bus/pci/devices/*/reset).

> 

> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>


Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>


Thanks,
Mani

> ---

>  drivers/bus/mhi/pci_generic.c | 121 +++++++++++++++++++++++++++++++++++++-----

>  1 file changed, 108 insertions(+), 13 deletions(-)

> 

> diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c

> index 077595c..b2307e7 100644

> --- a/drivers/bus/mhi/pci_generic.c

> +++ b/drivers/bus/mhi/pci_generic.c

> @@ -8,6 +8,7 @@

>   * Copyright (C) 2020 Linaro Ltd <loic.poulain@linaro.org>

>   */

>  

> +#include <linux/delay.h>

>  #include <linux/device.h>

>  #include <linux/mhi.h>

>  #include <linux/module.h>

> @@ -15,6 +16,7 @@

>  

>  #define MHI_PCI_DEFAULT_BAR_NUM 0

>  

> +#define MHI_POST_RESET_DELAY_MS 500

>  /**

>   * struct mhi_pci_dev_info - MHI PCI device specific information

>   * @config: MHI controller configuration

> @@ -177,6 +179,16 @@ static const struct pci_device_id mhi_pci_id_table[] = {

>  };

>  MODULE_DEVICE_TABLE(pci, mhi_pci_id_table);

>  

> +enum mhi_pci_device_status {

> +	MHI_PCI_DEV_STARTED,

> +};

> +

> +struct mhi_pci_device {

> +	struct mhi_controller mhi_cntrl;

> +	struct pci_saved_state *pci_state;

> +	unsigned long status;

> +};

> +

>  static int mhi_pci_read_reg(struct mhi_controller *mhi_cntrl,

>  			    void __iomem *addr, u32 *out)

>  {

> @@ -196,6 +208,20 @@ static void mhi_pci_status_cb(struct mhi_controller *mhi_cntrl,

>  	/* Nothing to do for now */

>  }

>  

> +static bool mhi_pci_is_alive(struct mhi_controller *mhi_cntrl)

> +{

> +	struct pci_dev *pdev = to_pci_dev(mhi_cntrl->cntrl_dev);

> +	u16 vendor = 0;

> +

> +	if (pci_read_config_word(pdev, PCI_VENDOR_ID, &vendor))

> +		return false;

> +

> +	if (vendor == (u16) ~0 || vendor == 0)

> +		return false;

> +

> +	return true;

> +}

> +

>  static int mhi_pci_claim(struct mhi_controller *mhi_cntrl,

>  			 unsigned int bar_num, u64 dma_mask)

>  {

> @@ -291,16 +317,20 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)

>  {

>  	const struct mhi_pci_dev_info *info = (struct mhi_pci_dev_info *) id->driver_data;

>  	const struct mhi_controller_config *mhi_cntrl_config;

> +	struct mhi_pci_device *mhi_pdev;

>  	struct mhi_controller *mhi_cntrl;

>  	int err;

>  

>  	dev_dbg(&pdev->dev, "MHI PCI device found: %s\n", info->name);

>  

> -	mhi_cntrl = mhi_alloc_controller();

> -	if (!mhi_cntrl)

> +	/* mhi_pdev.mhi_cntrl must be zero-initialized */

> +	mhi_pdev = devm_kzalloc(&pdev->dev, sizeof(*mhi_pdev), GFP_KERNEL);

> +	if (!mhi_pdev)

>  		return -ENOMEM;

>  

>  	mhi_cntrl_config = info->config;

> +	mhi_cntrl = &mhi_pdev->mhi_cntrl;

> +

>  	mhi_cntrl->cntrl_dev = &pdev->dev;

>  	mhi_cntrl->iova_start = 0;

>  	mhi_cntrl->iova_stop = DMA_BIT_MASK(info->dma_data_width);

> @@ -315,17 +345,21 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)

>  

>  	err = mhi_pci_claim(mhi_cntrl, info->bar_num, DMA_BIT_MASK(info->dma_data_width));

>  	if (err)

> -		goto err_release;

> +		return err;

>  

>  	err = mhi_pci_get_irqs(mhi_cntrl, mhi_cntrl_config);

>  	if (err)

> -		goto err_release;

> +		return err;

> +

> +	pci_set_drvdata(pdev, mhi_pdev);

>  

> -	pci_set_drvdata(pdev, mhi_cntrl);

> +	/* Have stored pci confspace at hand for restore in sudden PCI error */

> +	pci_save_state(pdev);

> +	mhi_pdev->pci_state = pci_store_saved_state(pdev);

>  

>  	err = mhi_register_controller(mhi_cntrl, mhi_cntrl_config);

>  	if (err)

> -		goto err_release;

> +		return err;

>  

>  	/* MHI bus does not power up the controller by default */

>  	err = mhi_prepare_for_power_up(mhi_cntrl);

> @@ -340,33 +374,94 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)

>  		goto err_unprepare;

>  	}

>  

> +	set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status);

> +

>  	return 0;

>  

>  err_unprepare:

>  	mhi_unprepare_after_power_down(mhi_cntrl);

>  err_unregister:

>  	mhi_unregister_controller(mhi_cntrl);

> -err_release:

> -	mhi_free_controller(mhi_cntrl);

>  

>  	return err;

>  }

>  

>  static void mhi_pci_remove(struct pci_dev *pdev)

>  {

> -	struct mhi_controller *mhi_cntrl = pci_get_drvdata(pdev);

> +	struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);

> +	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;

> +

> +	if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) {

> +		mhi_power_down(mhi_cntrl, true);

> +		mhi_unprepare_after_power_down(mhi_cntrl);

> +	}

>  

> -	mhi_power_down(mhi_cntrl, true);

> -	mhi_unprepare_after_power_down(mhi_cntrl);

>  	mhi_unregister_controller(mhi_cntrl);

> -	mhi_free_controller(mhi_cntrl);

>  }

>  

> +static void mhi_pci_reset_prepare(struct pci_dev *pdev)

> +{

> +	struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);

> +	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;

> +

> +	dev_info(&pdev->dev, "reset\n");

> +

> +	/* Clean up MHI state */

> +	if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) {

> +		mhi_power_down(mhi_cntrl, false);

> +		mhi_unprepare_after_power_down(mhi_cntrl);

> +	}

> +

> +	/* cause internal device reset */

> +	mhi_soc_reset(mhi_cntrl);

> +

> +	/* Be sure device reset has been executed */

> +	msleep(MHI_POST_RESET_DELAY_MS);

> +}

> +

> +static void mhi_pci_reset_done(struct pci_dev *pdev)

> +{

> +	struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);

> +	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;

> +	int err;

> +

> +	/* Restore initial known working PCI state */

> +	pci_load_saved_state(pdev, mhi_pdev->pci_state);

> +	pci_restore_state(pdev);

> +

> +	/* Is device status available ? */

> +	if (!mhi_pci_is_alive(mhi_cntrl)) {

> +		dev_err(&pdev->dev, "reset failed\n");

> +		return;

> +	}

> +

> +	err = mhi_prepare_for_power_up(mhi_cntrl);

> +	if (err) {

> +		dev_err(&pdev->dev, "failed to prepare MHI controller\n");

> +		return;

> +	}

> +

> +	err = mhi_sync_power_up(mhi_cntrl);

> +	if (err) {

> +		dev_err(&pdev->dev, "failed to power up MHI controller\n");

> +		mhi_unprepare_after_power_down(mhi_cntrl);

> +		return;

> +	}

> +

> +	set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status);

> +}

> +

> +static const struct pci_error_handlers mhi_pci_err_handler = {

> +	.reset_prepare = mhi_pci_reset_prepare,

> +	.reset_done = mhi_pci_reset_done,

> +};

> +

>  static struct pci_driver mhi_pci_driver = {

>  	.name		= "mhi-pci-generic",

>  	.id_table	= mhi_pci_id_table,

>  	.probe		= mhi_pci_probe,

> -	.remove		= mhi_pci_remove

> +	.remove		= mhi_pci_remove,

> +	.err_handler	= &mhi_pci_err_handler,

>  };

>  module_pci_driver(mhi_pci_driver);

>  

> -- 

> 2.7.4

>
diff mbox series

Patch

diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c
index 077595c..b2307e7 100644
--- a/drivers/bus/mhi/pci_generic.c
+++ b/drivers/bus/mhi/pci_generic.c
@@ -8,6 +8,7 @@ 
  * Copyright (C) 2020 Linaro Ltd <loic.poulain@linaro.org>
  */
 
+#include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/mhi.h>
 #include <linux/module.h>
@@ -15,6 +16,7 @@ 
 
 #define MHI_PCI_DEFAULT_BAR_NUM 0
 
+#define MHI_POST_RESET_DELAY_MS 500
 /**
  * struct mhi_pci_dev_info - MHI PCI device specific information
  * @config: MHI controller configuration
@@ -177,6 +179,16 @@  static const struct pci_device_id mhi_pci_id_table[] = {
 };
 MODULE_DEVICE_TABLE(pci, mhi_pci_id_table);
 
+enum mhi_pci_device_status {
+	MHI_PCI_DEV_STARTED,
+};
+
+struct mhi_pci_device {
+	struct mhi_controller mhi_cntrl;
+	struct pci_saved_state *pci_state;
+	unsigned long status;
+};
+
 static int mhi_pci_read_reg(struct mhi_controller *mhi_cntrl,
 			    void __iomem *addr, u32 *out)
 {
@@ -196,6 +208,20 @@  static void mhi_pci_status_cb(struct mhi_controller *mhi_cntrl,
 	/* Nothing to do for now */
 }
 
+static bool mhi_pci_is_alive(struct mhi_controller *mhi_cntrl)
+{
+	struct pci_dev *pdev = to_pci_dev(mhi_cntrl->cntrl_dev);
+	u16 vendor = 0;
+
+	if (pci_read_config_word(pdev, PCI_VENDOR_ID, &vendor))
+		return false;
+
+	if (vendor == (u16) ~0 || vendor == 0)
+		return false;
+
+	return true;
+}
+
 static int mhi_pci_claim(struct mhi_controller *mhi_cntrl,
 			 unsigned int bar_num, u64 dma_mask)
 {
@@ -291,16 +317,20 @@  static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	const struct mhi_pci_dev_info *info = (struct mhi_pci_dev_info *) id->driver_data;
 	const struct mhi_controller_config *mhi_cntrl_config;
+	struct mhi_pci_device *mhi_pdev;
 	struct mhi_controller *mhi_cntrl;
 	int err;
 
 	dev_dbg(&pdev->dev, "MHI PCI device found: %s\n", info->name);
 
-	mhi_cntrl = mhi_alloc_controller();
-	if (!mhi_cntrl)
+	/* mhi_pdev.mhi_cntrl must be zero-initialized */
+	mhi_pdev = devm_kzalloc(&pdev->dev, sizeof(*mhi_pdev), GFP_KERNEL);
+	if (!mhi_pdev)
 		return -ENOMEM;
 
 	mhi_cntrl_config = info->config;
+	mhi_cntrl = &mhi_pdev->mhi_cntrl;
+
 	mhi_cntrl->cntrl_dev = &pdev->dev;
 	mhi_cntrl->iova_start = 0;
 	mhi_cntrl->iova_stop = DMA_BIT_MASK(info->dma_data_width);
@@ -315,17 +345,21 @@  static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	err = mhi_pci_claim(mhi_cntrl, info->bar_num, DMA_BIT_MASK(info->dma_data_width));
 	if (err)
-		goto err_release;
+		return err;
 
 	err = mhi_pci_get_irqs(mhi_cntrl, mhi_cntrl_config);
 	if (err)
-		goto err_release;
+		return err;
+
+	pci_set_drvdata(pdev, mhi_pdev);
 
-	pci_set_drvdata(pdev, mhi_cntrl);
+	/* Have stored pci confspace at hand for restore in sudden PCI error */
+	pci_save_state(pdev);
+	mhi_pdev->pci_state = pci_store_saved_state(pdev);
 
 	err = mhi_register_controller(mhi_cntrl, mhi_cntrl_config);
 	if (err)
-		goto err_release;
+		return err;
 
 	/* MHI bus does not power up the controller by default */
 	err = mhi_prepare_for_power_up(mhi_cntrl);
@@ -340,33 +374,94 @@  static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		goto err_unprepare;
 	}
 
+	set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status);
+
 	return 0;
 
 err_unprepare:
 	mhi_unprepare_after_power_down(mhi_cntrl);
 err_unregister:
 	mhi_unregister_controller(mhi_cntrl);
-err_release:
-	mhi_free_controller(mhi_cntrl);
 
 	return err;
 }
 
 static void mhi_pci_remove(struct pci_dev *pdev)
 {
-	struct mhi_controller *mhi_cntrl = pci_get_drvdata(pdev);
+	struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);
+	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
+
+	if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) {
+		mhi_power_down(mhi_cntrl, true);
+		mhi_unprepare_after_power_down(mhi_cntrl);
+	}
 
-	mhi_power_down(mhi_cntrl, true);
-	mhi_unprepare_after_power_down(mhi_cntrl);
 	mhi_unregister_controller(mhi_cntrl);
-	mhi_free_controller(mhi_cntrl);
 }
 
+static void mhi_pci_reset_prepare(struct pci_dev *pdev)
+{
+	struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);
+	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
+
+	dev_info(&pdev->dev, "reset\n");
+
+	/* Clean up MHI state */
+	if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) {
+		mhi_power_down(mhi_cntrl, false);
+		mhi_unprepare_after_power_down(mhi_cntrl);
+	}
+
+	/* cause internal device reset */
+	mhi_soc_reset(mhi_cntrl);
+
+	/* Be sure device reset has been executed */
+	msleep(MHI_POST_RESET_DELAY_MS);
+}
+
+static void mhi_pci_reset_done(struct pci_dev *pdev)
+{
+	struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);
+	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
+	int err;
+
+	/* Restore initial known working PCI state */
+	pci_load_saved_state(pdev, mhi_pdev->pci_state);
+	pci_restore_state(pdev);
+
+	/* Is device status available ? */
+	if (!mhi_pci_is_alive(mhi_cntrl)) {
+		dev_err(&pdev->dev, "reset failed\n");
+		return;
+	}
+
+	err = mhi_prepare_for_power_up(mhi_cntrl);
+	if (err) {
+		dev_err(&pdev->dev, "failed to prepare MHI controller\n");
+		return;
+	}
+
+	err = mhi_sync_power_up(mhi_cntrl);
+	if (err) {
+		dev_err(&pdev->dev, "failed to power up MHI controller\n");
+		mhi_unprepare_after_power_down(mhi_cntrl);
+		return;
+	}
+
+	set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status);
+}
+
+static const struct pci_error_handlers mhi_pci_err_handler = {
+	.reset_prepare = mhi_pci_reset_prepare,
+	.reset_done = mhi_pci_reset_done,
+};
+
 static struct pci_driver mhi_pci_driver = {
 	.name		= "mhi-pci-generic",
 	.id_table	= mhi_pci_id_table,
 	.probe		= mhi_pci_probe,
-	.remove		= mhi_pci_remove
+	.remove		= mhi_pci_remove,
+	.err_handler	= &mhi_pci_err_handler,
 };
 module_pci_driver(mhi_pci_driver);