diff mbox series

[v3,06/27] ocxl: Tally up the LPC memory on a link & allow it to be mapped

Message ID 20200221032720.33893-7-alastair@au1.ibm.com
State New, archived
Headers show
Series Add support for OpenCAPI Persistent Memory devices | expand

Commit Message

Alastair D'Silva Feb. 21, 2020, 3:26 a.m. UTC
From: Alastair D'Silva <alastair@d-silva.org>

Tally up the LPC memory on an OpenCAPI link & allow it to be mapped

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
---
 drivers/misc/ocxl/core.c          | 10 ++++++
 drivers/misc/ocxl/link.c          | 53 +++++++++++++++++++++++++++++++
 drivers/misc/ocxl/ocxl_internal.h | 33 +++++++++++++++++++
 3 files changed, 96 insertions(+)

Comments

Andrew Donnellan Feb. 24, 2020, 5:25 a.m. UTC | #1
On 21/2/20 2:26 pm, Alastair D'Silva wrote:
> From: Alastair D'Silva <alastair@d-silva.org>
> 
> Tally up the LPC memory on an OpenCAPI link & allow it to be mapped
> 
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>

This commit message is a bit short and could do with some further 
explanation.

In particular - it's worth explaining why the tracking of available LPC 
memory needs to be done at a link level, because a single OpenCAPI card 
can have multiple PCI functions, each with multiple AFUs which define an 
amount of LPC memory they have, even if the common case is expected to 
be a single function with a single AFU and thus one LPC area per link.

Snowpatch has a few checkpatch issues to report:

https://openpower.xyz/job/snowpatch/job/snowpatch-linux-checkpatch/11800//artifact/linux/checkpatch.log

The code generally looks okay to me.

> diff --git a/drivers/misc/ocxl/ocxl_internal.h b/drivers/misc/ocxl/ocxl_internal.h
> index 198e4e4bc51d..d0c8c4838f42 100644
> --- a/drivers/misc/ocxl/ocxl_internal.h
> +++ b/drivers/misc/ocxl/ocxl_internal.h
> @@ -142,4 +142,37 @@ int ocxl_irq_offset_to_id(struct ocxl_context *ctx, u64 offset);
>   u64 ocxl_irq_id_to_offset(struct ocxl_context *ctx, int irq_id);
>   void ocxl_afu_irq_free_all(struct ocxl_context *ctx);
>   
> +/**
> + * ocxl_link_add_lpc_mem() - Increment the amount of memory required by an OpenCAPI link
> + *
> + * @link_handle: The OpenCAPI link handle
> + * @offset: The offset of the memory to add
> + * @size: The amount of memory to increment by
> + *
> + * Returns 0 on success, negative on overflow
> + */

I think "amount of memory required" isn't the best way to express this.

Might as well explicitly say -EINVAL on overflow.
Alastair D'Silva Feb. 24, 2020, 5:36 a.m. UTC | #2
On Mon, 2020-02-24 at 16:25 +1100, Andrew Donnellan wrote:
> On 21/2/20 2:26 pm, Alastair D'Silva wrote:
> > From: Alastair D'Silva <alastair@d-silva.org>
> > 
> > Tally up the LPC memory on an OpenCAPI link & allow it to be mapped
> > 
> > Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> 
> This commit message is a bit short and could do with some further 
> explanation.
> 
> In particular - it's worth explaining why the tracking of available
> LPC 
> memory needs to be done at a link level, because a single OpenCAPI
> card 
> can have multiple PCI functions, each with multiple AFUs which define
> an 
> amount of LPC memory they have, even if the common case is expected
> to 
> be a single function with a single AFU and thus one LPC area per
> link.

Ok

> 
> Snowpatch has a few checkpatch issues to report:
> 
> https://openpower.xyz/job/snowpatch/job/snowpatch-linux-checkpatch/11800//artifact/linux/checkpatch.log
> 

Gah, I could have sworn I ran checkpatch against this :/

> The code generally looks okay to me.
> 
> > diff --git a/drivers/misc/ocxl/ocxl_internal.h
> > b/drivers/misc/ocxl/ocxl_internal.h
> > index 198e4e4bc51d..d0c8c4838f42 100644
> > --- a/drivers/misc/ocxl/ocxl_internal.h
> > +++ b/drivers/misc/ocxl/ocxl_internal.h
> > @@ -142,4 +142,37 @@ int ocxl_irq_offset_to_id(struct ocxl_context
> > *ctx, u64 offset);
> >   u64 ocxl_irq_id_to_offset(struct ocxl_context *ctx, int irq_id);
> >   void ocxl_afu_irq_free_all(struct ocxl_context *ctx);
> >   
> > +/**
> > + * ocxl_link_add_lpc_mem() - Increment the amount of memory
> > required by an OpenCAPI link
> > + *
> > + * @link_handle: The OpenCAPI link handle
> > + * @offset: The offset of the memory to add
> > + * @size: The amount of memory to increment by
> > + *
> > + * Returns 0 on success, negative on overflow
> > + */
> 
> I think "amount of memory required" isn't the best way to express
> this.
> 
> Might as well explicitly say -EINVAL on overflow.
> 

Ok
Frederic Barrat Feb. 25, 2020, 4:30 p.m. UTC | #3
Le 21/02/2020 à 04:26, Alastair D'Silva a écrit :
> From: Alastair D'Silva <alastair@d-silva.org>
> 
> Tally up the LPC memory on an OpenCAPI link & allow it to be mapped
> 
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> ---
>   drivers/misc/ocxl/core.c          | 10 ++++++
>   drivers/misc/ocxl/link.c          | 53 +++++++++++++++++++++++++++++++
>   drivers/misc/ocxl/ocxl_internal.h | 33 +++++++++++++++++++
>   3 files changed, 96 insertions(+)
> 
> diff --git a/drivers/misc/ocxl/core.c b/drivers/misc/ocxl/core.c
> index b7a09b21ab36..2531c6cf19a0 100644
> --- a/drivers/misc/ocxl/core.c
> +++ b/drivers/misc/ocxl/core.c
> @@ -230,8 +230,18 @@ static int configure_afu(struct ocxl_afu *afu, u8 afu_idx, struct pci_dev *dev)
>   	if (rc)
>   		goto err_free_pasid;
>   
> +	if (afu->config.lpc_mem_size || afu->config.special_purpose_mem_size) {
> +		rc = ocxl_link_add_lpc_mem(afu->fn->link, afu->config.lpc_mem_offset,
> +					   afu->config.lpc_mem_size +
> +					   afu->config.special_purpose_mem_size);
> +		if (rc)
> +			goto err_free_mmio;
> +	}
> +
>   	return 0;
>   
> +err_free_mmio:
> +	unmap_mmio_areas(afu);
>   err_free_pasid:
>   	reclaim_afu_pasid(afu);
>   err_free_actag:
> diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
> index 58d111afd9f6..1e039cc5ebe5 100644
> --- a/drivers/misc/ocxl/link.c
> +++ b/drivers/misc/ocxl/link.c
> @@ -84,6 +84,11 @@ struct ocxl_link {
>   	int dev;
>   	atomic_t irq_available;
>   	struct spa *spa;
> +	struct mutex lpc_mem_lock; /* protects lpc_mem & lpc_mem_sz */
> +	u64 lpc_mem_sz; /* Total amount of LPC memory presented on the link */
> +	u64 lpc_mem;
> +	int lpc_consumers;
> +
>   	void *platform_data;
>   };
>   static struct list_head links_list = LIST_HEAD_INIT(links_list);
> @@ -396,6 +401,8 @@ static int alloc_link(struct pci_dev *dev, int PE_mask, struct ocxl_link **out_l
>   	if (rc)
>   		goto err_spa;
>   
> +	mutex_init(&link->lpc_mem_lock);
> +
>   	/* platform specific hook */
>   	rc = pnv_ocxl_spa_setup(dev, link->spa->spa_mem, PE_mask,
>   				&link->platform_data);
> @@ -711,3 +718,49 @@ void ocxl_link_free_irq(void *link_handle, int hw_irq)
>   	atomic_inc(&link->irq_available);
>   }
>   EXPORT_SYMBOL_GPL(ocxl_link_free_irq);
> +
> +int ocxl_link_add_lpc_mem(void *link_handle, u64 offset, u64 size)
> +{
> +	struct ocxl_link *link = (struct ocxl_link *) link_handle;
> +
> +	// Check for overflow
> +	if (offset > (offset + size))
> +		return -EINVAL;
> +
> +	mutex_lock(&link->lpc_mem_lock);
> +	link->lpc_mem_sz = max(link->lpc_mem_sz, offset + size);
> +
> +	mutex_unlock(&link->lpc_mem_lock);
> +
> +	return 0;
> +}
> +
> +u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev)
> +{
> +	struct ocxl_link *link = (struct ocxl_link *) link_handle;
> +
> +	mutex_lock(&link->lpc_mem_lock);
> +
> +	if(!link->lpc_mem)
> +		link->lpc_mem = pnv_ocxl_platform_lpc_setup(pdev, link->lpc_mem_sz);
> +
> +	if(link->lpc_mem)
> +		link->lpc_consumers++;
> +	mutex_unlock(&link->lpc_mem_lock);
> +
> +	return link->lpc_mem;
> +}
> +
> +void ocxl_link_lpc_release(void *link_handle, struct pci_dev *pdev)
> +{
> +	struct ocxl_link *link = (struct ocxl_link *) link_handle;
> +
> +	mutex_lock(&link->lpc_mem_lock);
> +	WARN_ON(--link->lpc_consumers < 0);


Here, we always decrement the lpc_consumers count. However, it was only 
incremented if the mapping was setup correctly in opal.

We could arguably claim that ocxl_link_lpc_release() should only be 
called if ocxl_link_lpc_map() succeeded, but it would make error path 
handling easier if we only decrement the lpc_consumers count if 
link->lpc_mem is set. So that we can just call ocxl_link_lpc_release() 
in error paths without having to worry about triggering the WARN_ON message.

   Fred



> +	if (link->lpc_consumers == 0) {
> +		pnv_ocxl_platform_lpc_release(pdev);
> +		link->lpc_mem = 0;
> +	}
> +
> +	mutex_unlock(&link->lpc_mem_lock);
> +}
> diff --git a/drivers/misc/ocxl/ocxl_internal.h b/drivers/misc/ocxl/ocxl_internal.h
> index 198e4e4bc51d..d0c8c4838f42 100644
> --- a/drivers/misc/ocxl/ocxl_internal.h
> +++ b/drivers/misc/ocxl/ocxl_internal.h
> @@ -142,4 +142,37 @@ int ocxl_irq_offset_to_id(struct ocxl_context *ctx, u64 offset);
>   u64 ocxl_irq_id_to_offset(struct ocxl_context *ctx, int irq_id);
>   void ocxl_afu_irq_free_all(struct ocxl_context *ctx);
>   
> +/**
> + * ocxl_link_add_lpc_mem() - Increment the amount of memory required by an OpenCAPI link
> + *
> + * @link_handle: The OpenCAPI link handle
> + * @offset: The offset of the memory to add
> + * @size: The amount of memory to increment by
> + *
> + * Returns 0 on success, negative on overflow
> + */
> +int ocxl_link_add_lpc_mem(void *link_handle, u64 offset, u64 size);
> +
> +/**
> + * ocxl_link_lpc_map() - Map the LPC memory for an OpenCAPI device
> + * Since LPC memory belongs to a link, the whole LPC memory available
> + * on the link must be mapped in order to make it accessible to a device.
> + * @link_handle: The OpenCAPI link handle
> + * @pdev: A device that is on the link
> + *
> + * Returns the address of the mapped LPC memory, or 0 on error
> + */
> +u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev);
> +
> +/**
> + * ocxl_link_lpc_release() - Release the LPC memory device for an OpenCAPI device
> + *
> + * Offlines LPC memory on an OpenCAPI link for a device. If this is the
> + * last device on the link to release the memory, unmap it from the link.
> + *
> + * @link_handle: The OpenCAPI link handle
> + * @pdev: A device that is on the link
> + */
> +void ocxl_link_lpc_release(void *link_handle, struct pci_dev *pdev);
> +
>   #endif /* _OCXL_INTERNAL_H_ */
>
Alastair D'Silva Feb. 26, 2020, 12:29 a.m. UTC | #4
On Tue, 2020-02-25 at 17:30 +0100, Frederic Barrat wrote:
> 
> Le 21/02/2020 à 04:26, Alastair D'Silva a écrit :
> > From: Alastair D'Silva <alastair@d-silva.org>
> > 
> > Tally up the LPC memory on an OpenCAPI link & allow it to be mapped
> > 
> > Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> > ---
> >   drivers/misc/ocxl/core.c          | 10 ++++++
> >   drivers/misc/ocxl/link.c          | 53
> > +++++++++++++++++++++++++++++++
> >   drivers/misc/ocxl/ocxl_internal.h | 33 +++++++++++++++++++
> >   3 files changed, 96 insertions(+)
> > 
> > diff --git a/drivers/misc/ocxl/core.c b/drivers/misc/ocxl/core.c
> > index b7a09b21ab36..2531c6cf19a0 100644
> > --- a/drivers/misc/ocxl/core.c
> > +++ b/drivers/misc/ocxl/core.c
> > @@ -230,8 +230,18 @@ static int configure_afu(struct ocxl_afu *afu,
> > u8 afu_idx, struct pci_dev *dev)
> >   	if (rc)
> >   		goto err_free_pasid;
> >   
> > +	if (afu->config.lpc_mem_size || afu-
> > >config.special_purpose_mem_size) {
> > +		rc = ocxl_link_add_lpc_mem(afu->fn->link, afu-
> > >config.lpc_mem_offset,
> > +					   afu->config.lpc_mem_size +
> > +					   afu-
> > >config.special_purpose_mem_size);
> > +		if (rc)
> > +			goto err_free_mmio;
> > +	}
> > +
> >   	return 0;
> >   
> > +err_free_mmio:
> > +	unmap_mmio_areas(afu);
> >   err_free_pasid:
> >   	reclaim_afu_pasid(afu);
> >   err_free_actag:
> > diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
> > index 58d111afd9f6..1e039cc5ebe5 100644
> > --- a/drivers/misc/ocxl/link.c
> > +++ b/drivers/misc/ocxl/link.c
> > @@ -84,6 +84,11 @@ struct ocxl_link {
> >   	int dev;
> >   	atomic_t irq_available;
> >   	struct spa *spa;
> > +	struct mutex lpc_mem_lock; /* protects lpc_mem & lpc_mem_sz */
> > +	u64 lpc_mem_sz; /* Total amount of LPC memory presented on the
> > link */
> > +	u64 lpc_mem;
> > +	int lpc_consumers;
> > +
> >   	void *platform_data;
> >   };
> >   static struct list_head links_list = LIST_HEAD_INIT(links_list);
> > @@ -396,6 +401,8 @@ static int alloc_link(struct pci_dev *dev, int
> > PE_mask, struct ocxl_link **out_l
> >   	if (rc)
> >   		goto err_spa;
> >   
> > +	mutex_init(&link->lpc_mem_lock);
> > +
> >   	/* platform specific hook */
> >   	rc = pnv_ocxl_spa_setup(dev, link->spa->spa_mem, PE_mask,
> >   				&link->platform_data);
> > @@ -711,3 +718,49 @@ void ocxl_link_free_irq(void *link_handle, int
> > hw_irq)
> >   	atomic_inc(&link->irq_available);
> >   }
> >   EXPORT_SYMBOL_GPL(ocxl_link_free_irq);
> > +
> > +int ocxl_link_add_lpc_mem(void *link_handle, u64 offset, u64 size)
> > +{
> > +	struct ocxl_link *link = (struct ocxl_link *) link_handle;
> > +
> > +	// Check for overflow
> > +	if (offset > (offset + size))
> > +		return -EINVAL;
> > +
> > +	mutex_lock(&link->lpc_mem_lock);
> > +	link->lpc_mem_sz = max(link->lpc_mem_sz, offset + size);
> > +
> > +	mutex_unlock(&link->lpc_mem_lock);
> > +
> > +	return 0;
> > +}
> > +
> > +u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev)
> > +{
> > +	struct ocxl_link *link = (struct ocxl_link *) link_handle;
> > +
> > +	mutex_lock(&link->lpc_mem_lock);
> > +
> > +	if(!link->lpc_mem)
> > +		link->lpc_mem = pnv_ocxl_platform_lpc_setup(pdev, link-
> > >lpc_mem_sz);
> > +
> > +	if(link->lpc_mem)
> > +		link->lpc_consumers++;
> > +	mutex_unlock(&link->lpc_mem_lock);
> > +
> > +	return link->lpc_mem;
> > +}
> > +
> > +void ocxl_link_lpc_release(void *link_handle, struct pci_dev
> > *pdev)
> > +{
> > +	struct ocxl_link *link = (struct ocxl_link *) link_handle;
> > +
> > +	mutex_lock(&link->lpc_mem_lock);
> > +	WARN_ON(--link->lpc_consumers < 0);
> 
> Here, we always decrement the lpc_consumers count. However, it was
> only 
> incremented if the mapping was setup correctly in opal.
> 
> We could arguably claim that ocxl_link_lpc_release() should only be 
> called if ocxl_link_lpc_map() succeeded, but it would make error
> path 
> handling easier if we only decrement the lpc_consumers count if 
> link->lpc_mem is set. So that we can just call
> ocxl_link_lpc_release() 
> in error paths without having to worry about triggering the WARN_ON
> message.
> 
>    Fred
> 
> 

Ok, this makes sense.

> 
> > +	if (link->lpc_consumers == 0) {
> > +		pnv_ocxl_platform_lpc_release(pdev);
> > +		link->lpc_mem = 0;
> > +	}
> > +
> > +	mutex_unlock(&link->lpc_mem_lock);
> > +}
> > diff --git a/drivers/misc/ocxl/ocxl_internal.h
> > b/drivers/misc/ocxl/ocxl_internal.h
> > index 198e4e4bc51d..d0c8c4838f42 100644
> > --- a/drivers/misc/ocxl/ocxl_internal.h
> > +++ b/drivers/misc/ocxl/ocxl_internal.h
> > @@ -142,4 +142,37 @@ int ocxl_irq_offset_to_id(struct ocxl_context
> > *ctx, u64 offset);
> >   u64 ocxl_irq_id_to_offset(struct ocxl_context *ctx, int irq_id);
> >   void ocxl_afu_irq_free_all(struct ocxl_context *ctx);
> >   
> > +/**
> > + * ocxl_link_add_lpc_mem() - Increment the amount of memory
> > required by an OpenCAPI link
> > + *
> > + * @link_handle: The OpenCAPI link handle
> > + * @offset: The offset of the memory to add
> > + * @size: The amount of memory to increment by
> > + *
> > + * Returns 0 on success, negative on overflow
> > + */
> > +int ocxl_link_add_lpc_mem(void *link_handle, u64 offset, u64
> > size);
> > +
> > +/**
> > + * ocxl_link_lpc_map() - Map the LPC memory for an OpenCAPI device
> > + * Since LPC memory belongs to a link, the whole LPC memory
> > available
> > + * on the link must be mapped in order to make it accessible to a
> > device.
> > + * @link_handle: The OpenCAPI link handle
> > + * @pdev: A device that is on the link
> > + *
> > + * Returns the address of the mapped LPC memory, or 0 on error
> > + */
> > +u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev);
> > +
> > +/**
> > + * ocxl_link_lpc_release() - Release the LPC memory device for an
> > OpenCAPI device
> > + *
> > + * Offlines LPC memory on an OpenCAPI link for a device. If this
> > is the
> > + * last device on the link to release the memory, unmap it from
> > the link.
> > + *
> > + * @link_handle: The OpenCAPI link handle
> > + * @pdev: A device that is on the link
> > + */
> > +void ocxl_link_lpc_release(void *link_handle, struct pci_dev
> > *pdev);
> > +
> >   #endif /* _OCXL_INTERNAL_H_ */
> >
diff mbox series

Patch

diff --git a/drivers/misc/ocxl/core.c b/drivers/misc/ocxl/core.c
index b7a09b21ab36..2531c6cf19a0 100644
--- a/drivers/misc/ocxl/core.c
+++ b/drivers/misc/ocxl/core.c
@@ -230,8 +230,18 @@  static int configure_afu(struct ocxl_afu *afu, u8 afu_idx, struct pci_dev *dev)
 	if (rc)
 		goto err_free_pasid;
 
+	if (afu->config.lpc_mem_size || afu->config.special_purpose_mem_size) {
+		rc = ocxl_link_add_lpc_mem(afu->fn->link, afu->config.lpc_mem_offset,
+					   afu->config.lpc_mem_size +
+					   afu->config.special_purpose_mem_size);
+		if (rc)
+			goto err_free_mmio;
+	}
+
 	return 0;
 
+err_free_mmio:
+	unmap_mmio_areas(afu);
 err_free_pasid:
 	reclaim_afu_pasid(afu);
 err_free_actag:
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index 58d111afd9f6..1e039cc5ebe5 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -84,6 +84,11 @@  struct ocxl_link {
 	int dev;
 	atomic_t irq_available;
 	struct spa *spa;
+	struct mutex lpc_mem_lock; /* protects lpc_mem & lpc_mem_sz */
+	u64 lpc_mem_sz; /* Total amount of LPC memory presented on the link */
+	u64 lpc_mem;
+	int lpc_consumers;
+
 	void *platform_data;
 };
 static struct list_head links_list = LIST_HEAD_INIT(links_list);
@@ -396,6 +401,8 @@  static int alloc_link(struct pci_dev *dev, int PE_mask, struct ocxl_link **out_l
 	if (rc)
 		goto err_spa;
 
+	mutex_init(&link->lpc_mem_lock);
+
 	/* platform specific hook */
 	rc = pnv_ocxl_spa_setup(dev, link->spa->spa_mem, PE_mask,
 				&link->platform_data);
@@ -711,3 +718,49 @@  void ocxl_link_free_irq(void *link_handle, int hw_irq)
 	atomic_inc(&link->irq_available);
 }
 EXPORT_SYMBOL_GPL(ocxl_link_free_irq);
+
+int ocxl_link_add_lpc_mem(void *link_handle, u64 offset, u64 size)
+{
+	struct ocxl_link *link = (struct ocxl_link *) link_handle;
+
+	// Check for overflow
+	if (offset > (offset + size))
+		return -EINVAL;
+
+	mutex_lock(&link->lpc_mem_lock);
+	link->lpc_mem_sz = max(link->lpc_mem_sz, offset + size);
+
+	mutex_unlock(&link->lpc_mem_lock);
+
+	return 0;
+}
+
+u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev)
+{
+	struct ocxl_link *link = (struct ocxl_link *) link_handle;
+
+	mutex_lock(&link->lpc_mem_lock);
+
+	if(!link->lpc_mem)
+		link->lpc_mem = pnv_ocxl_platform_lpc_setup(pdev, link->lpc_mem_sz);
+
+	if(link->lpc_mem)
+		link->lpc_consumers++;
+	mutex_unlock(&link->lpc_mem_lock);
+
+	return link->lpc_mem;
+}
+
+void ocxl_link_lpc_release(void *link_handle, struct pci_dev *pdev)
+{
+	struct ocxl_link *link = (struct ocxl_link *) link_handle;
+
+	mutex_lock(&link->lpc_mem_lock);
+	WARN_ON(--link->lpc_consumers < 0);
+	if (link->lpc_consumers == 0) {
+		pnv_ocxl_platform_lpc_release(pdev);
+		link->lpc_mem = 0;
+	}
+
+	mutex_unlock(&link->lpc_mem_lock);
+}
diff --git a/drivers/misc/ocxl/ocxl_internal.h b/drivers/misc/ocxl/ocxl_internal.h
index 198e4e4bc51d..d0c8c4838f42 100644
--- a/drivers/misc/ocxl/ocxl_internal.h
+++ b/drivers/misc/ocxl/ocxl_internal.h
@@ -142,4 +142,37 @@  int ocxl_irq_offset_to_id(struct ocxl_context *ctx, u64 offset);
 u64 ocxl_irq_id_to_offset(struct ocxl_context *ctx, int irq_id);
 void ocxl_afu_irq_free_all(struct ocxl_context *ctx);
 
+/**
+ * ocxl_link_add_lpc_mem() - Increment the amount of memory required by an OpenCAPI link
+ *
+ * @link_handle: The OpenCAPI link handle
+ * @offset: The offset of the memory to add
+ * @size: The amount of memory to increment by
+ *
+ * Returns 0 on success, negative on overflow
+ */
+int ocxl_link_add_lpc_mem(void *link_handle, u64 offset, u64 size);
+
+/**
+ * ocxl_link_lpc_map() - Map the LPC memory for an OpenCAPI device
+ * Since LPC memory belongs to a link, the whole LPC memory available
+ * on the link must be mapped in order to make it accessible to a device.
+ * @link_handle: The OpenCAPI link handle
+ * @pdev: A device that is on the link
+ *
+ * Returns the address of the mapped LPC memory, or 0 on error
+ */
+u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev);
+
+/**
+ * ocxl_link_lpc_release() - Release the LPC memory device for an OpenCAPI device
+ *
+ * Offlines LPC memory on an OpenCAPI link for a device. If this is the
+ * last device on the link to release the memory, unmap it from the link.
+ *
+ * @link_handle: The OpenCAPI link handle
+ * @pdev: A device that is on the link
+ */
+void ocxl_link_lpc_release(void *link_handle, struct pci_dev *pdev);
+
 #endif /* _OCXL_INTERNAL_H_ */