| Message ID | 20241004050742.140664-4-dlemoal@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Improve PCI memory mapping API | expand |
On Fri, Oct 04, 2024 at 02:07:38PM +0900, Damien Le Moal wrote: > Some endpoint controllers have requirements on the alignment of the > controller physical memory address that must be used to map a RC PCI > address region. For instance, the rockchip endpoint controller uses > at most the lower 20 bits of a physical memory address region as the > lower bits of an RC PCI address. For mapping a PCI address region of > size bytes starting from pci_addr, the exact number of address bits > used is the number of address bits changing in the address range > [pci_addr..pci_addr + size - 1]. > > For this example, this creates the following constraints: > 1) The offset into the controller physical memory allocated for a > mapping depends on the mapping size *and* the starting PCI address > for the mapping. > 2) A mapping size cannot exceed the controller windows size (1MB) minus > the offset needed into the allocated physical memory, which can end > up being a smaller size than the desired mapping size. > > Handling these constraints independently of the controller being used > in an endpoint function driver is not possible with the current EPC > API as only the ->align field in struct pci_epc_features is provided > and used for BAR (inbound ATU mappings) mapping. A new API is needed > for function drivers to discover mapping constraints and handle > non-static requirements based on the RC PCI address range to access. > > Introduce the function pci_epc_map_align() and the endpoint controller > operation ->map_align to allow endpoint function drivers to obtain the > size and the offset into a controller address region that must be > allocated and mapped to access an RC PCI address region. The size > of the mapping provided by pci_epc_map_align() can then be used as the > size argument for the function pci_epc_mem_alloc_addr(). > The offset into the allocated controller memory provided can be used to > correctly handle data transfers. > > For endpoint controllers that have PCI address alignment constraints, > pci_epc_map_align() may indicate upon return an effective PCI address > region mapping size that is smaller (but not 0) than the requested PCI > address region size. For such case, an endpoint function driver must > handle data accesses over the desired PCI address range in fragments, > by repeatedly using pci_epc_map_align() over the PCI address range. > > The controller operation ->map_align is optional: controllers that do > not have any alignment constraints for mapping a RC PCI address region > do not need to implement this operation. For such controllers, > pci_epc_map_align() always returns the mapping size as equal to the > requested size of the PCI region and an offset equal to 0. > > The new structure struct pci_epc_map is introduced to represent a > mapping start PCI address, mapping effective size, the size and offset > into the controller memory needed for mapping the PCI address region as > well as the physical and virtual CPU addresses of the mapping (phys_base > and virt_base fields). For convenience, the physical and virtual CPU > addresses within that mapping to access the target RC PCI address region > are also provided (phys_addr and virt_addr 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 | 56 +++++++++++++++++++++++++++++ > include/linux/pci-epc.h | 37 +++++++++++++++++++ > 2 files changed, 93 insertions(+) > > diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c > index b854f1bab26f..48dd3c28ac4c 100644 > --- a/drivers/pci/endpoint/pci-epc-core.c > +++ b/drivers/pci/endpoint/pci-epc-core.c > @@ -435,6 +435,62 @@ void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no, > } > EXPORT_SYMBOL_GPL(pci_epc_unmap_addr); > > +/** > + * pci_epc_map_align() - Get the offset into and the size of a controller memory > + * address region needed to map a RC PCI address region > + * @epc: the EPC device on which address is allocated > + * @func_no: the physical endpoint function number in the EPC device > + * @vfunc_no: the virtual endpoint function number in the physical function > + * @pci_addr: The RC PCI address to map > + * @pci_size: the number of bytes to map starting from @pci_addr > + * @map: populate here the actual size and offset into the controller memory > + * that must be allocated for the mapping > + * > + * If defined, invoke the controller map_align operation to obtain the size and > + * the offset into a controller address region that must be allocated to map > + * @pci_size bytes of the RC PCI address space starting from @pci_addr. > + * > + * On return, @map->pci_size indicates the effective size of the mapping that > + * can be handled by the controller. This size may be smaller than the requested > + * @pci_size. In such case, the endpoint function driver must handle the mapping > + * using several fragments. The offset into the controller memory for the > + * effective mapping of the RC PCI address range > + * @pci_addr..@pci_addr+@map->pci_size is indicated by @map->map_ofst. > + * > + * If the target controller does not define a map_align operation, it is assumed > + * that the controller has no PCI address mapping alignment constraint. > + */ > +int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no, > + u64 pci_addr, size_t pci_size, struct pci_epc_map *map) > +{ > + int ret; > + > + if (!pci_epc_function_is_valid(epc, func_no, vfunc_no)) > + return -EINVAL; > + > + if (!pci_size || !map) > + return -EINVAL; > + > + memset(map, 0, sizeof(*map)); > + map->pci_addr = pci_addr; Since the kdoc says that @map->pci_size might be smaller than the requested size, I assume that you are only temporarily storing pci_size in map here, and that map_align() might overwrite this value. Perhaps add a comment here that explains that map_align() might/will overwrite this value. > + map->pci_size = pci_size; > + > + if (!epc->ops->map_align) { > + /* Assume that the EP controller has no alignment constraint */ > + map->map_pci_addr = pci_addr; > + map->map_size = pci_size; > + map->map_ofst = 0; > + return 0; > + } > + > + mutex_lock(&epc->lock); > + ret = epc->ops->map_align(epc, func_no, vfunc_no, map); > + mutex_unlock(&epc->lock); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(pci_epc_map_align); > + > /** > * pci_epc_map_addr() - map CPU address to PCI address > * @epc: the EPC device on which address is allocated > diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h > index 42ef06136bd1..9df8a83e8d10 100644 > --- a/include/linux/pci-epc.h > +++ b/include/linux/pci-epc.h > @@ -32,11 +32,44 @@ pci_epc_interface_string(enum pci_epc_interface_type type) > } > } > > +/** > + * struct pci_epc_map - information about EPC memory for mapping a RC PCI > + * address range > + * @pci_addr: start address of the RC PCI address range to map > + * @pci_size: size of the RC PCI address range mapped from @pci_addr > + * @map_pci_addr: RC PCI address used as the first address mapped (may be lower > + * than @pci_addr) > + * @map_size: size of the controller memory needed for mapping the RC PCI address > + * range @pci_addr..@pci_addr+@pci_size > + * @map_ofst: offset into the mapped controller memory to access @pci_addr > + * @phys_base: base physical address of the allocated EPC memory for mapping the > + * RC PCI address range > + * @phys_addr: physical address at which @pci_addr is mapped > + * @virt_base: base virtual address of the allocated EPC memory for mapping the > + * RC PCI address range > + * @virt_addr: virtual address at which @pci_addr is mapped > + */ > +struct pci_epc_map { > + phys_addr_t pci_addr; > + size_t pci_size; > + > + phys_addr_t map_pci_addr; > + size_t map_size; > + phys_addr_t map_ofst; > + > + phys_addr_t phys_base; > + phys_addr_t phys_addr; > + void __iomem *virt_base; > + void __iomem *virt_addr; > +}; > + > /** > * struct pci_epc_ops - set of function pointers for performing EPC operations > * @write_header: ops to populate configuration space header > * @set_bar: ops to configure the BAR > * @clear_bar: ops to reset the BAR > + * @map_align: operation to get the size and offset into a controller memory > + * window needed to map an RC PCI address region > * @map_addr: ops to map CPU address to PCI address > * @unmap_addr: ops to unmap CPU address and PCI address > * @set_msi: ops to set the requested number of MSI interrupts in the MSI > @@ -61,6 +94,8 @@ struct pci_epc_ops { > struct pci_epf_bar *epf_bar); > void (*clear_bar)(struct pci_epc *epc, u8 func_no, u8 vfunc_no, > struct pci_epf_bar *epf_bar); > + int (*map_align)(struct pci_epc *epc, u8 func_no, u8 vfunc_no, > + struct pci_epc_map *map); > int (*map_addr)(struct pci_epc *epc, u8 func_no, u8 vfunc_no, > phys_addr_t addr, u64 pci_addr, size_t size); > void (*unmap_addr)(struct pci_epc *epc, u8 func_no, u8 vfunc_no, > @@ -241,6 +276,8 @@ int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no, > struct pci_epf_bar *epf_bar); > void pci_epc_clear_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no, > struct pci_epf_bar *epf_bar); > +int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no, > + u64 pci_addr, size_t size, struct pci_epc_map *map); > int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no, > phys_addr_t phys_addr, > u64 pci_addr, size_t size); > -- > 2.46.2 > Reviewed-by: Niklas Cassel <cassel@kernel.org>
diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c index b854f1bab26f..48dd3c28ac4c 100644 --- a/drivers/pci/endpoint/pci-epc-core.c +++ b/drivers/pci/endpoint/pci-epc-core.c @@ -435,6 +435,62 @@ void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no, } EXPORT_SYMBOL_GPL(pci_epc_unmap_addr); +/** + * pci_epc_map_align() - Get the offset into and the size of a controller memory + * address region needed to map a RC PCI address region + * @epc: the EPC device on which address is allocated + * @func_no: the physical endpoint function number in the EPC device + * @vfunc_no: the virtual endpoint function number in the physical function + * @pci_addr: The RC PCI address to map + * @pci_size: the number of bytes to map starting from @pci_addr + * @map: populate here the actual size and offset into the controller memory + * that must be allocated for the mapping + * + * If defined, invoke the controller map_align operation to obtain the size and + * the offset into a controller address region that must be allocated to map + * @pci_size bytes of the RC PCI address space starting from @pci_addr. + * + * On return, @map->pci_size indicates the effective size of the mapping that + * can be handled by the controller. This size may be smaller than the requested + * @pci_size. In such case, the endpoint function driver must handle the mapping + * using several fragments. The offset into the controller memory for the + * effective mapping of the RC PCI address range + * @pci_addr..@pci_addr+@map->pci_size is indicated by @map->map_ofst. + * + * If the target controller does not define a map_align operation, it is assumed + * that the controller has no PCI address mapping alignment constraint. + */ +int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no, + u64 pci_addr, size_t pci_size, struct pci_epc_map *map) +{ + int ret; + + if (!pci_epc_function_is_valid(epc, func_no, vfunc_no)) + return -EINVAL; + + if (!pci_size || !map) + return -EINVAL; + + memset(map, 0, sizeof(*map)); + map->pci_addr = pci_addr; + map->pci_size = pci_size; + + if (!epc->ops->map_align) { + /* Assume that the EP controller has no alignment constraint */ + map->map_pci_addr = pci_addr; + map->map_size = pci_size; + map->map_ofst = 0; + return 0; + } + + mutex_lock(&epc->lock); + ret = epc->ops->map_align(epc, func_no, vfunc_no, map); + mutex_unlock(&epc->lock); + + return ret; +} +EXPORT_SYMBOL_GPL(pci_epc_map_align); + /** * pci_epc_map_addr() - map CPU address to PCI address * @epc: the EPC device on which address is allocated diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h index 42ef06136bd1..9df8a83e8d10 100644 --- a/include/linux/pci-epc.h +++ b/include/linux/pci-epc.h @@ -32,11 +32,44 @@ pci_epc_interface_string(enum pci_epc_interface_type type) } } +/** + * struct pci_epc_map - information about EPC memory for mapping a RC PCI + * address range + * @pci_addr: start address of the RC PCI address range to map + * @pci_size: size of the RC PCI address range mapped from @pci_addr + * @map_pci_addr: RC PCI address used as the first address mapped (may be lower + * than @pci_addr) + * @map_size: size of the controller memory needed for mapping the RC PCI address + * range @pci_addr..@pci_addr+@pci_size + * @map_ofst: offset into the mapped controller memory to access @pci_addr + * @phys_base: base physical address of the allocated EPC memory for mapping the + * RC PCI address range + * @phys_addr: physical address at which @pci_addr is mapped + * @virt_base: base virtual address of the allocated EPC memory for mapping the + * RC PCI address range + * @virt_addr: virtual address at which @pci_addr is mapped + */ +struct pci_epc_map { + phys_addr_t pci_addr; + size_t pci_size; + + phys_addr_t map_pci_addr; + size_t map_size; + phys_addr_t map_ofst; + + phys_addr_t phys_base; + phys_addr_t phys_addr; + void __iomem *virt_base; + void __iomem *virt_addr; +}; + /** * struct pci_epc_ops - set of function pointers for performing EPC operations * @write_header: ops to populate configuration space header * @set_bar: ops to configure the BAR * @clear_bar: ops to reset the BAR + * @map_align: operation to get the size and offset into a controller memory + * window needed to map an RC PCI address region * @map_addr: ops to map CPU address to PCI address * @unmap_addr: ops to unmap CPU address and PCI address * @set_msi: ops to set the requested number of MSI interrupts in the MSI @@ -61,6 +94,8 @@ struct pci_epc_ops { struct pci_epf_bar *epf_bar); void (*clear_bar)(struct pci_epc *epc, u8 func_no, u8 vfunc_no, struct pci_epf_bar *epf_bar); + int (*map_align)(struct pci_epc *epc, u8 func_no, u8 vfunc_no, + struct pci_epc_map *map); int (*map_addr)(struct pci_epc *epc, u8 func_no, u8 vfunc_no, phys_addr_t addr, u64 pci_addr, size_t size); void (*unmap_addr)(struct pci_epc *epc, u8 func_no, u8 vfunc_no, @@ -241,6 +276,8 @@ int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no, struct pci_epf_bar *epf_bar); void pci_epc_clear_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no, struct pci_epf_bar *epf_bar); +int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no, + u64 pci_addr, size_t size, struct pci_epc_map *map); int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no, phys_addr_t phys_addr, u64 pci_addr, size_t size);