diff mbox series

[v3,4/7] PCI: endpoint: Introduce pci_epc_mem_map()/unmap()

Message ID 20241004050742.140664-5-dlemoal@kernel.org (mailing list archive)
State New
Headers show
Series Improve PCI memory mapping API | expand

Commit Message

Damien Le Moal Oct. 4, 2024, 5:07 a.m. UTC 
Introduce the function pci_epc_mem_map() to facilitate controller memory
address allocation and mapping to a RC PCI address region in endpoint
function drivers.

This function first uses pci_epc_map_align() to determine the controller
memory address size (and offset into) depending on the controller
address alignment constraints. The result of this function is used to
allocate a controller physical memory region using
pci_epc_mem_alloc_addr() and map that memory to the RC PCI address
space with pci_epc_map_addr().

Since pci_epc_map_align() may indicate that the effective mapping
of a PCI address region is smaller than the user requested size,
pci_epc_mem_map() may only partially map the RC PCI address region
specified. It is the responsibility of the caller (an endpoint function
driver) to handle such smaller mapping.

The counterpart of pci_epc_mem_map() to unmap and free the controller
memory address region is pci_epc_mem_unmap().

Both functions operate using a struct pci_epc_map data structure
Endpoint function drivers can use struct pci_epc_map to access the
mapped RC PCI address region using the ->virt_addr and ->pci_size
fields.

Co-developed-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
Signed-off-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/endpoint/pci-epc-core.c | 78 +++++++++++++++++++++++++++++
 include/linux/pci-epc.h             |  4 ++
 2 files changed, 82 insertions(+)

Comments

Niklas Cassel Oct. 4, 2024, 11:47 a.m. UTC | #1 
On Fri, Oct 04, 2024 at 02:07:39PM +0900, Damien Le Moal wrote:
> Introduce the function pci_epc_mem_map() to facilitate controller memory
> address allocation and mapping to a RC PCI address region in endpoint
> function drivers.
> 
> This function first uses pci_epc_map_align() to determine the controller
> memory address size (and offset into) depending on the controller
> address alignment constraints. The result of this function is used to
> allocate a controller physical memory region using
> pci_epc_mem_alloc_addr() and map that memory to the RC PCI address
> space with pci_epc_map_addr().
> 
> Since pci_epc_map_align() may indicate that the effective mapping
> of a PCI address region is smaller than the user requested size,
> pci_epc_mem_map() may only partially map the RC PCI address region
> specified. It is the responsibility of the caller (an endpoint function
> driver) to handle such smaller mapping.
> 
> The counterpart of pci_epc_mem_map() to unmap and free the controller
> memory address region is pci_epc_mem_unmap().
> 
> Both functions operate using a struct pci_epc_map data structure
> Endpoint function drivers can use struct pci_epc_map to access the
> mapped RC PCI address region using the ->virt_addr and ->pci_size
> fields.
> 
> Co-developed-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
> Signed-off-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>  drivers/pci/endpoint/pci-epc-core.c | 78 +++++++++++++++++++++++++++++
>  include/linux/pci-epc.h             |  4 ++
>  2 files changed, 82 insertions(+)
> 
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index 48dd3c28ac4c..5f3b0a86d6fe 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -522,6 +522,84 @@ int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  }
>  EXPORT_SYMBOL_GPL(pci_epc_map_addr);
>  
> +/**
> + * pci_epc_mem_map() - allocate and map a PCI address to a CPU address
> + * @epc: the EPC device on which the CPU address is to be allocated and mapped
> + * @func_no: the physical endpoint function number in the EPC device
> + * @vfunc_no: the virtual endpoint function number in the physical function
> + * @pci_addr: PCI address to which the CPU address should be mapped
> + * @pci_size: the number of bytes to map starting from @pci_addr
> + * @map: where to return the mapping information
> + *
> + * Allocate a controller memory address region and map it to a RC PCI address
> + * region, taking into account the controller physical address mapping
> + * constraints using pci_epc_map_align().
> + * The effective size of the PCI address range mapped from @pci_addr is
> + * indicated by @map->pci_size. This size may be less than the requested
> + * @pci_size. The local virtual CPU address for the mapping is indicated by
> + * @map->virt_addr (@map->phys_addr indicates the physical address).
> + * The size and CPU address of the controller memory allocated and mapped are
> + * respectively indicated by @map->map_size and @map->virt_base (and
> + * @map->phys_base).
> + *
> + * Returns 0 on success and a negative error code in case of error.
> + */
> +int pci_epc_mem_map(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +		    u64 pci_addr, size_t pci_size, struct pci_epc_map *map)
> +{
> +	int ret;
> +
> +	ret = pci_epc_map_align(epc, func_no, vfunc_no, pci_addr, pci_size, map);
> +	if (ret)
> +		return ret;
> +
> +	map->virt_base = pci_epc_mem_alloc_addr(epc, &map->phys_base,
> +						map->map_size);
> +	if (!map->virt_base)
> +		return -ENOMEM;
> +
> +	map->phys_addr = map->phys_base + map->map_ofst;
> +	map->virt_addr = map->virt_base + map->map_ofst;
> +
> +	ret = pci_epc_map_addr(epc, func_no, vfunc_no, map->phys_base,
> +			       map->map_pci_addr, map->map_size);
> +	if (ret) {
> +		pci_epc_mem_free_addr(epc, map->phys_base, map->virt_base,
> +				      map->map_size);
> +		map->virt_base = 0;
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(pci_epc_mem_map);
> +
> +/**
> + * pci_epc_mem_unmap() - unmap and free a CPU address region
> + * @epc: the EPC device on which the CPU address is allocated and mapped
> + * @func_no: the physical endpoint function number in the EPC device
> + * @vfunc_no: the virtual endpoint function number in the physical function
> + * @map: the mapping information
> + *
> + * Unmap and free a CPU address region that was allocated and mapped with
> + * pci_epc_mem_map().
> + */
> +void pci_epc_mem_unmap(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +		       struct pci_epc_map *map)
> +{
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
> +		return;
> +
> +	if (!map || !map->virt_base)
> +		return;
> +
> +	pci_epc_unmap_addr(epc, func_no, vfunc_no, map->phys_base);
> +	pci_epc_mem_free_addr(epc, map->phys_base, map->virt_base,
> +			      map->map_size);
> +	map->map_size = 0;
> +}
> +EXPORT_SYMBOL_GPL(pci_epc_mem_unmap);
> +
>  /**
>   * pci_epc_clear_bar() - reset the BAR
>   * @epc: the EPC device for which the BAR has to be cleared
> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> index 9df8a83e8d10..97d2fbb740fd 100644
> --- a/include/linux/pci-epc.h
> +++ b/include/linux/pci-epc.h
> @@ -315,6 +315,10 @@ void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
>  				     phys_addr_t *phys_addr, size_t size);
>  void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
>  			   void __iomem *virt_addr, size_t size);
> +int pci_epc_mem_map(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +		    u64 pci_addr, size_t pci_size, struct pci_epc_map *map);
> +void pci_epc_mem_unmap(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +		       struct pci_epc_map *map);
>  
>  #else
>  static inline void pci_epc_init_notify(struct pci_epc *epc)
> -- 
> 2.46.2
> 

Naming is one of the hardest problems in computer science :)

Perhaps:
s/pci_epc_mem_map()/pci_epc_mem_alloc_map()/
s/pci_epc_mem_unmap()/pci_epc_mem_free_unmap()/

is slightly more clear that this both allocates and maps.


Regardless:
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Damien Le Moal Oct. 4, 2024, 1:29 p.m. UTC | #2 
On 10/4/24 20:47, Niklas Cassel wrote:
> Naming is one of the hardest problems in computer science :)

Yep.

> Perhaps:
> s/pci_epc_mem_map()/pci_epc_mem_alloc_map()/
> s/pci_epc_mem_unmap()/pci_epc_mem_free_unmap()/
> 
> is slightly more clear that this both allocates and maps.

Sure, but I consider the allocation an implementation detail of the function.
And I really prefer the shorter function names :)

> Regardless:
> Reviewed-by: Niklas Cassel <cassel@kernel.org>

Thanks.
diff mbox series

Patch

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index 48dd3c28ac4c..5f3b0a86d6fe 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -522,6 +522,84 @@  int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 }
 EXPORT_SYMBOL_GPL(pci_epc_map_addr);
 
+/**
+ * pci_epc_mem_map() - allocate and map a PCI address to a CPU address
+ * @epc: the EPC device on which the CPU address is to be allocated and mapped
+ * @func_no: the physical endpoint function number in the EPC device
+ * @vfunc_no: the virtual endpoint function number in the physical function
+ * @pci_addr: PCI address to which the CPU address should be mapped
+ * @pci_size: the number of bytes to map starting from @pci_addr
+ * @map: where to return the mapping information
+ *
+ * Allocate a controller memory address region and map it to a RC PCI address
+ * region, taking into account the controller physical address mapping
+ * constraints using pci_epc_map_align().
+ * The effective size of the PCI address range mapped from @pci_addr is
+ * indicated by @map->pci_size. This size may be less than the requested
+ * @pci_size. The local virtual CPU address for the mapping is indicated by
+ * @map->virt_addr (@map->phys_addr indicates the physical address).
+ * The size and CPU address of the controller memory allocated and mapped are
+ * respectively indicated by @map->map_size and @map->virt_base (and
+ * @map->phys_base).
+ *
+ * Returns 0 on success and a negative error code in case of error.
+ */
+int pci_epc_mem_map(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
+		    u64 pci_addr, size_t pci_size, struct pci_epc_map *map)
+{
+	int ret;
+
+	ret = pci_epc_map_align(epc, func_no, vfunc_no, pci_addr, pci_size, map);
+	if (ret)
+		return ret;
+
+	map->virt_base = pci_epc_mem_alloc_addr(epc, &map->phys_base,
+						map->map_size);
+	if (!map->virt_base)
+		return -ENOMEM;
+
+	map->phys_addr = map->phys_base + map->map_ofst;
+	map->virt_addr = map->virt_base + map->map_ofst;
+
+	ret = pci_epc_map_addr(epc, func_no, vfunc_no, map->phys_base,
+			       map->map_pci_addr, map->map_size);
+	if (ret) {
+		pci_epc_mem_free_addr(epc, map->phys_base, map->virt_base,
+				      map->map_size);
+		map->virt_base = 0;
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pci_epc_mem_map);
+
+/**
+ * pci_epc_mem_unmap() - unmap and free a CPU address region
+ * @epc: the EPC device on which the CPU address is allocated and mapped
+ * @func_no: the physical endpoint function number in the EPC device
+ * @vfunc_no: the virtual endpoint function number in the physical function
+ * @map: the mapping information
+ *
+ * Unmap and free a CPU address region that was allocated and mapped with
+ * pci_epc_mem_map().
+ */
+void pci_epc_mem_unmap(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
+		       struct pci_epc_map *map)
+{
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
+		return;
+
+	if (!map || !map->virt_base)
+		return;
+
+	pci_epc_unmap_addr(epc, func_no, vfunc_no, map->phys_base);
+	pci_epc_mem_free_addr(epc, map->phys_base, map->virt_base,
+			      map->map_size);
+	map->map_size = 0;
+}
+EXPORT_SYMBOL_GPL(pci_epc_mem_unmap);
+
 /**
  * pci_epc_clear_bar() - reset the BAR
  * @epc: the EPC device for which the BAR has to be cleared
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index 9df8a83e8d10..97d2fbb740fd 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -315,6 +315,10 @@  void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
 				     phys_addr_t *phys_addr, size_t size);
 void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
 			   void __iomem *virt_addr, size_t size);
+int pci_epc_mem_map(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
+		    u64 pci_addr, size_t pci_size, struct pci_epc_map *map);
+void pci_epc_mem_unmap(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
+		       struct pci_epc_map *map);
 
 #else
 static inline void pci_epc_init_notify(struct pci_epc *epc)