Re: [PATCH v7 2/4] firmware: ti_sci: add support for restoring IRQs during resume

[Nishanth Menon <nm@ti.com>]

On 10:35-20260506, Thomas Richard (TI) wrote:
> Some DM-Firmware are not able to restore the IRQ context after a
> suspend-resume. The IRQ_CONTEXT_LOST firmware capability has been
> introduced to identify this characteristic. In this case the
> responsibility is delegated to the ti_sci driver, which maintains an
> internal list of all requested IRQs. This list is updated on each
> set()/free() operation, and all IRQs are restored during the resume_noirq()
> phase.
> 
> Reviewed-by: Dhruva Gole <d-gole@ti.com>
> Reviewed-by: Kendall Willis <k-willis@ti.com>
> Signed-off-by: Thomas Richard (TI) <thomas.richard@bootlin.com>
> ---

coccicheck reports two additional warnings at this patch:
+drivers/firmware/ti_sci.c:2495:1-7: preceding lock on line 2454
+drivers/firmware/ti_sci.c:2420:1-7: preceding lock on line 2378

>  drivers/firmware/ti_sci.c | 201 +++++++++++++++++++++++++++++++++++++++++++---
>  drivers/firmware/ti_sci.h |   2 +
>  2 files changed, 191 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
> index eaeaaae94142..531ac3aa38b8 100644
> --- a/drivers/firmware/ti_sci.c
> +++ b/drivers/firmware/ti_sci.c
> @@ -12,11 +12,13 @@
>  #include <linux/cpu.h>
>  #include <linux/debugfs.h>
>  #include <linux/export.h>
> +#include <linux/hashtable.h>
>  #include <linux/io.h>
>  #include <linux/iopoll.h>
>  #include <linux/kernel.h>
>  #include <linux/mailbox_client.h>
>  #include <linux/module.h>
> +#include <linux/mutex.h>
>  #include <linux/of.h>
>  #include <linux/of_platform.h>
>  #include <linux/platform_device.h>
> @@ -87,6 +89,16 @@ struct ti_sci_desc {
>  	int max_msg_size;
>  };
>  
> +/**
> + * struct ti_sci_irq - Description of allocated irqs
> + * @node: Link to hash table
> + * @desc: Description of the irq
> + */
> +struct ti_sci_irq {
> +	struct hlist_node node;
> +	struct ti_sci_msg_req_manage_irq desc;
> +};
> +
>  /**
>   * struct ti_sci_info - Structure representing a TI SCI instance
>   * @dev:	Device pointer
> @@ -101,6 +113,8 @@ struct ti_sci_desc {
>   * @chan_rx:	Receive mailbox channel
>   * @minfo:	Message info
>   * @node:	list head
> + * @irqs:	List of allocated irqs
> + * @irq_lock:	Protection for irq hash list
>   * @host_id:	Host ID
>   * @fw_caps:	FW/SoC low power capabilities
>   * @users:	Number of users of this instance
> @@ -118,6 +132,8 @@ struct ti_sci_info {
>  	struct mbox_chan *chan_rx;
>  	struct ti_sci_xfers_info minfo;
>  	struct list_head node;
> +	DECLARE_HASHTABLE(irqs, 8);
> +	struct mutex irq_lock;

No action needed: checkpatch flags this as not documented, when it is
clearly documented above.

>  	u8 host_id;
>  	u64 fw_caps;
>  	/* protected by ti_sci_list_mutex */
> @@ -2301,6 +2317,32 @@ static int ti_sci_manage_irq(const struct ti_sci_handle *handle,
>  	return ret;
>  }
>  
> +/**
> + * ti_sci_irq_hash() - Helper API to compute irq hash for the hash table.
> + * @irq:	irq to hash
> + *
> + * Return: the computed hash value.
> + */
> +static int ti_sci_irq_hash(struct ti_sci_msg_req_manage_irq *irq)
> +{
> +	return irq->src_id ^ irq->src_index;
> +}
> +
> +/**
> + * ti_sci_irq_equal() - Helper API to compare two irqs (generic headers are not
> + *                       compared)
> + * @irq_a:	irq_a to compare
> + * @irq_b:	irq_b to compare
> + *
> + * Return: true if the two irqs are equal, else false.
> + */
> +static bool ti_sci_irq_equal(struct ti_sci_msg_req_manage_irq *irq_a,
> +			     struct ti_sci_msg_req_manage_irq *irq_b)
> +{
> +	return !memcmp(&irq_a->valid_params, &irq_b->valid_params,
> +		       sizeof(*irq_a) - sizeof(irq_a->hdr));
> +}
> +
>  /**
>   * ti_sci_set_irq() - Helper api to configure the irq route between the
>   *		      requested source and destination
> @@ -2324,15 +2366,60 @@ static int ti_sci_set_irq(const struct ti_sci_handle *handle, u32 valid_params,
>  			  u16 dst_host_irq, u16 ia_id, u16 vint,
>  			  u16 global_event, u8 vint_status_bit, u8 s_host)
>  {
> +	struct ti_sci_info *info = handle_to_ti_sci_info(handle);
> +	struct ti_sci_msg_req_manage_irq *desc;
> +	struct ti_sci_irq *irq;
> +	int ret;
> +
> +	/*
> +	 * Lock for set_irq() and free_irq() to keep the IRQ hash list
> +	 * consistent only if MSG_FLAG_CAPS_LPM_IRQ_CONTEXT_LOST is set. Else
> +	 * IRQ hash list is not used.
> +	 */
> +	if (info->fw_caps & MSG_FLAG_CAPS_LPM_IRQ_CONTEXT_LOST)
> +		mutex_lock(&info->irq_lock);
> +
>  	pr_debug("%s: IRQ set with valid_params = 0x%x from src = %d, index = %d, to dst = %d, irq = %d,via ia_id = %d, vint = %d, global event = %d,status_bit = %d\n",
>  		 __func__, valid_params, src_id, src_index,
>  		 dst_id, dst_host_irq, ia_id, vint, global_event,
>  		 vint_status_bit);
>  
> -	return ti_sci_manage_irq(handle, valid_params, src_id, src_index,
> -				 dst_id, dst_host_irq, ia_id, vint,
> -				 global_event, vint_status_bit, s_host,
> -				 TI_SCI_MSG_SET_IRQ);
> +	ret = ti_sci_manage_irq(handle, valid_params, src_id, src_index,
> +				dst_id, dst_host_irq, ia_id, vint,
> +				global_event, vint_status_bit, s_host,
> +				TI_SCI_MSG_SET_IRQ);
> +
> +	if (ret || !(info->fw_caps & MSG_FLAG_CAPS_LPM_IRQ_CONTEXT_LOST))
> +		goto end;
> +
> +	irq = kzalloc_obj(*irq, GFP_KERNEL);
> +	if (!irq) {
> +		ti_sci_manage_irq(handle, valid_params, src_id, src_index,
> +				  dst_id, dst_host_irq, ia_id, vint,
> +				  global_event, vint_status_bit, s_host,
> +				  TI_SCI_MSG_FREE_IRQ);
> +		ret = -ENOMEM;
> +		goto end;
> +	}
> +
> +	desc = &irq->desc;
> +	desc->valid_params = valid_params;
> +	desc->src_id = src_id;
> +	desc->src_index = src_index;
> +	desc->dst_id = dst_id;
> +	desc->dst_host_irq = dst_host_irq;
> +	desc->ia_id = ia_id;
> +	desc->vint = vint;
> +	desc->global_event = global_event;
> +	desc->vint_status_bit = vint_status_bit;
> +	desc->secondary_host = s_host;
> +
> +	hash_add(info->irqs, &irq->node, ti_sci_irq_hash(desc));
> +
> +end:
> +	if (info->fw_caps & MSG_FLAG_CAPS_LPM_IRQ_CONTEXT_LOST)
> +		mutex_unlock(&info->irq_lock);
> +	return ret;
>  }
>  
>  /**
> @@ -2358,15 +2445,56 @@ static int ti_sci_free_irq(const struct ti_sci_handle *handle, u32 valid_params,
>  			   u16 dst_host_irq, u16 ia_id, u16 vint,
>  			   u16 global_event, u8 vint_status_bit, u8 s_host)
>  {
> +	struct ti_sci_info *info = handle_to_ti_sci_info(handle);
> +	struct ti_sci_msg_req_manage_irq irq_desc;
> +	struct device *dev = info->dev;
> +	struct ti_sci_irq *this_irq;
> +	struct hlist_node *tmp_node;
> +	int ret;
> +
> +	if (info->fw_caps & MSG_FLAG_CAPS_LPM_IRQ_CONTEXT_LOST)
> +		mutex_lock(&info->irq_lock);
> +
>  	pr_debug("%s: IRQ release with valid_params = 0x%x from src = %d, index = %d, to dst = %d, irq = %d,via ia_id = %d, vint = %d, global event = %d,status_bit = %d\n",
>  		 __func__, valid_params, src_id, src_index,
>  		 dst_id, dst_host_irq, ia_id, vint, global_event,
>  		 vint_status_bit);
>  
> -	return ti_sci_manage_irq(handle, valid_params, src_id, src_index,
> -				 dst_id, dst_host_irq, ia_id, vint,
> -				 global_event, vint_status_bit, s_host,
> -				 TI_SCI_MSG_FREE_IRQ);
> +	ret = ti_sci_manage_irq(handle, valid_params, src_id, src_index,
> +				dst_id, dst_host_irq, ia_id, vint,
> +				global_event, vint_status_bit, s_host,
> +				TI_SCI_MSG_FREE_IRQ);
> +
> +	if (ret || !(info->fw_caps & MSG_FLAG_CAPS_LPM_IRQ_CONTEXT_LOST))
> +		goto end;
> +
> +	irq_desc.valid_params = valid_params;
> +	irq_desc.src_id = src_id;
> +	irq_desc.src_index = src_index;
> +	irq_desc.dst_id = dst_id;
> +	irq_desc.dst_host_irq = dst_host_irq;
> +	irq_desc.ia_id = ia_id;
> +	irq_desc.vint = vint;
> +	irq_desc.global_event = global_event;
> +	irq_desc.vint_status_bit = vint_status_bit;
> +	irq_desc.secondary_host = s_host;
> +
> +	hash_for_each_possible_safe(info->irqs, this_irq, tmp_node, node,
> +				    ti_sci_irq_hash(&irq_desc)) {
> +		if (ti_sci_irq_equal(&irq_desc, &this_irq->desc)) {
> +			hlist_del(&this_irq->node);
> +			kfree(this_irq);
> +			goto end;
> +		}
> +	}
> +
> +	dev_warn(dev, "%s: should not be here, IRQ was not found in hash list\n",
> +		 __func__);
> +
> +end:
> +	if (info->fw_caps & MSG_FLAG_CAPS_LPM_IRQ_CONTEXT_LOST)
> +		mutex_unlock(&info->irq_lock);
> +	return ret;
>  }
>  
>  /**
> @@ -3847,7 +3975,10 @@ static int ti_sci_suspend_noirq(struct device *dev)
>  static int ti_sci_resume_noirq(struct device *dev)
>  {
>  	struct ti_sci_info *info = dev_get_drvdata(dev);
> -	int ret = 0;
> +	struct ti_sci_msg_req_manage_irq *irq_desc;
> +	struct ti_sci_irq *irq;
> +	struct hlist_node *tmp_node;
> +	int ret = 0, err = 0, i;
>  	u32 source;
>  	u64 time;
>  	u8 pin;
> @@ -3859,13 +3990,50 @@ static int ti_sci_resume_noirq(struct device *dev)
>  			return ret;
>  	}
>  
> +	switch (pm_suspend_target_state) {
> +	case PM_SUSPEND_MEM:
> +		if (info->fw_caps & MSG_FLAG_CAPS_LPM_IRQ_CONTEXT_LOST) {
> +			hash_for_each_safe(info->irqs, i, tmp_node, irq, node) {
> +				irq_desc = &irq->desc;
> +				ret = ti_sci_manage_irq(&info->handle,
> +							irq_desc->valid_params,
> +							irq_desc->src_id,
> +							irq_desc->src_index,
> +							irq_desc->dst_id,
> +							irq_desc->dst_host_irq,
> +							irq_desc->ia_id,
> +							irq_desc->vint,
> +							irq_desc->global_event,
> +							irq_desc->vint_status_bit,
> +							irq_desc->secondary_host,
> +							TI_SCI_MSG_SET_IRQ);
> +				if (ret) {
> +					dev_err(dev, "failed to restore IRQ with valid_params = 0x%x from src = %d, index = %d, to dst = %d, irq = %d,via ia_id = %d, vint = %d, global event = %d,status_bit = %d\n",

space before via? overall this print is needed, but a bit umm.. we have
similar ones already..

> +						irq_desc->valid_params,
> +						irq_desc->src_id,
> +						irq_desc->src_index,
> +						irq_desc->dst_id,
> +						irq_desc->dst_host_irq,
> +						irq_desc->ia_id,
> +						irq_desc->vint,
> +						irq_desc->global_event,
> +						irq_desc->vint_status_bit);
> +					err = ret;
> +				}
> +			}
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +
>  	ret = ti_sci_msg_cmd_lpm_wake_reason(&info->handle, &source, &time, &pin, &mode);
>  	/* Do not fail to resume on error as the wake reason is not critical */
>  	if (!ret)
>  		dev_info(dev, "ti_sci: wakeup source:0x%x, pin:0x%x, mode:0x%x\n",
>  			 source, pin, mode);
>  
> -	return 0;
> +	return err;
>  }
>  
>  static void ti_sci_pm_complete(struct device *dev)
> @@ -4014,13 +4182,14 @@ static int ti_sci_probe(struct platform_device *pdev)
>  	}
>  
>  	ti_sci_msg_cmd_query_fw_caps(&info->handle, &info->fw_caps);
> -	dev_dbg(dev, "Detected firmware capabilities: %s%s%s%s%s%s\n",
> +	dev_dbg(dev, "Detected firmware capabilities: %s%s%s%s%s%s%s\n",
>  		info->fw_caps & MSG_FLAG_CAPS_GENERIC ? "Generic" : "",
>  		info->fw_caps & MSG_FLAG_CAPS_LPM_PARTIAL_IO ? " Partial-IO" : "",
>  		info->fw_caps & MSG_FLAG_CAPS_LPM_DM_MANAGED ? " DM-Managed" : "",
>  		info->fw_caps & MSG_FLAG_CAPS_LPM_ABORT ? " LPM-Abort" : "",
>  		info->fw_caps & MSG_FLAG_CAPS_IO_ISOLATION ? " IO-Isolation" : "",
> -		info->fw_caps & MSG_FLAG_CAPS_LPM_BOARDCFG_MANAGED ? " BoardConfig-Managed" : ""
> +		info->fw_caps & MSG_FLAG_CAPS_LPM_BOARDCFG_MANAGED ? " BoardConfig-Managed" : "",
> +		info->fw_caps & MSG_FLAG_CAPS_LPM_IRQ_CONTEXT_LOST ? " IRQ-Context-Lost" : ""
>  	);
>  
>  	ti_sci_setup_ops(info);
> @@ -4053,6 +4222,14 @@ static int ti_sci_probe(struct platform_device *pdev)
>  	list_add_tail(&info->node, &ti_sci_list);
>  	mutex_unlock(&ti_sci_list_mutex);
>  
> +	if (info->fw_caps & MSG_FLAG_CAPS_LPM_IRQ_CONTEXT_LOST) {
> +		ret = devm_mutex_init(dev, &info->irq_lock);
> +		if (ret)
> +			return ret;

If devm_mutex_init() fails, the function returns directly rather than
going through the out: label. All other error paths after the mailbox
channel allocations use goto out, which calls mbox_free_channel() for
both channels. Since mbox_request_channel_byname() is not a devm
allocation, those channels would not be freed by the devm cleanup path
on probe failure.

Does this leak info->chan_tx and info->chan_rx when devm_mutex_init()
returns an error?
> +
> +		hash_init(info->irqs);
> +	}
> +
>  	ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
>  	if (ret) {
>  		dev_err(dev, "platform_populate failed %pe\n", ERR_PTR(ret));
> diff --git a/drivers/firmware/ti_sci.h b/drivers/firmware/ti_sci.h
> index d90de59e29eb..67f16e8c69a1 100644
> --- a/drivers/firmware/ti_sci.h
> +++ b/drivers/firmware/ti_sci.h
> @@ -151,6 +151,7 @@ struct ti_sci_msg_req_reboot {
>   *		MSG_FLAG_CAPS_LPM_ABORT: Abort entry to LPM
>   *		MSG_FLAG_CAPS_IO_ISOLATION: IO Isolation support
>   *		MSG_FLAG_CAPS_LPM_BOARDCFG_MANAGED: LPM config done statically for the DM via boardcfg
> + *		MSG_FLAG_CAPS_LPM_IRQ_CONTEXT_LOST: DM is not able to restore IRQ context
>   *
>   * Response to a generic message with message type TI_SCI_MSG_QUERY_FW_CAPS
>   * providing currently available SOC/firmware capabilities. SoC that don't
> @@ -164,6 +165,7 @@ struct ti_sci_msg_resp_query_fw_caps {
>  #define MSG_FLAG_CAPS_LPM_ABORT		TI_SCI_MSG_FLAG(9)
>  #define MSG_FLAG_CAPS_IO_ISOLATION	TI_SCI_MSG_FLAG(7)
>  #define MSG_FLAG_CAPS_LPM_BOARDCFG_MANAGED	TI_SCI_MSG_FLAG(12)
> +#define MSG_FLAG_CAPS_LPM_IRQ_CONTEXT_LOST	TI_SCI_MSG_FLAG(14)
>  #define MSG_MASK_CAPS_LPM		GENMASK_ULL(4, 1)
>  	u64 fw_caps;
>  } __packed;
> 
> -- 
> 2.53.0
> 

-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D
https://ti.com/opensource