From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5B0BF19923C for ; Fri, 11 Oct 2024 12:07:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728648433; cv=none; b=k8b2HjuUY4X3ecBLkCI44jNm2+w1lyV5smgLTT1wi4P5D9bWXN3DhmqaXLpaSXRhIL5wWQMstT7Dfmtf8VsVLD8+kEu0pBgYMLhML7apLbeEoBhbaXcjxbf9Vidk225lzyT7mklEwwWtBnG9sbixniOBySKF5M/R5kwQHq3xOi8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728648433; c=relaxed/simple; bh=BWsa7EcpFA4GjTAB1nLOfIQu8ihGf+0FxFs3D4LaooU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=h7HOZWJIocN1jRmIYhIg6ShbREJOtzPH35SBr0lrhK9J3Zqic/I74z4b+bSQ29rosH85dWMN8jIzIfNhQ67hglqSrlFqFiZFw44xznEtRvp2SNr244XoGpfKKvMfmag8f+rPEcflGBBF5NgBMMC/uw3jqfkEiH++zO1oK5nBhTM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NexA34kq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NexA34kq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 807FCC4CEC3; Fri, 11 Oct 2024 12:07:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728648432; bh=BWsa7EcpFA4GjTAB1nLOfIQu8ihGf+0FxFs3D4LaooU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NexA34kqLzB4aRr9r5pJhvxOYjVIpz+3MEsgq8JTOVJk+IuvmOxr0B8VE12a8yJ/D 2Wi2U23pPvxk9NQsSde9BYF9ecmDkCI4o0wPglTOfw8r/LLobuEvmAw9RG+b4eng8m 8PNFzae9bzIZZgiDK9qbzuONbbvQYsm+9UeRZrZZ8iFRXk20kSkqX3NXbCh4q4n5Q2 D5aWt4pW+K7lLJ3GEblKRI/tXma+x6P1nrOHNlInX3xV0uGIs2I6UqqwD4Kll4yUGu rHdnWSwXsHFNWI6UNvWE8Stxjr+sKU/5ojkP+2RgsuVjNWiDQyrMEjc/p4LjEVxQuH udyTK1DtFJOMg== Date: Fri, 11 Oct 2024 14:07:07 +0200 From: Niklas Cassel To: Damien Le Moal Cc: Manivannan Sadhasivam , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Kishon Vijay Abraham I , Bjorn Helgaas , Lorenzo Pieralisi , Rob Herring , Jonathan Corbet , Jingoo Han , linux-pci@vger.kernel.org, Rick Wertenbroek Subject: Re: [PATCH v5 3/6] PCI: endpoint: Introduce pci_epc_mem_map()/unmap() Message-ID: References: <20241011120115.89756-1-dlemoal@kernel.org> <20241011120115.89756-4-dlemoal@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241011120115.89756-4-dlemoal@kernel.org> On Fri, Oct 11, 2024 at 09:01:12PM +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 endpoint controller of the RK3399 SoC > uses at most the lower 20 bits of a physical memory address region as > the lower bits of a RC PCI address region. 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 > but used for BAR (inbound ATU mappings) mapping only. 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 endpoint controller operation ->get_mem_map() to allow > the EPC core functions to obtain the size and the offset into a > controller address region that must be allocated and mapped to access > a RC PCI address region. The size of the mapping provided by the > get_mem_map() operation can then be used as the size argument for the > function pci_epc_mem_alloc_addr() and 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, get_mem_map() may indicate upon return an effective PCI > address region size that is smaller (but not 0) than the requested PCI > address region size. > > The controller ->get_mem_map() operation is optional: controllers that > do not have any alignment constraints for mapping RC PCI address regions > do not need to implement this operation. For such controllers, it is > always assumed that the mapping size is equal to the requested size of > the PCI region and that the mapping offset is 0. > > The function pci_epc_mem_map() is introduced to use this new controller > operation (if it is defined) to handle controller memory allocation and > mapping to a RC PCI address region in endpoint function drivers. > > This function first uses the ->get_mem_map() controller operation to > determine the controller memory address size (and offset into) needed > for mapping an RC PCI address region. The result of this function > operation is used to allocate a controller physical memory region using > pci_epc_mem_alloc_addr() and then to map that memory to the RC PCI > address space with pci_epc_map_addr(). > > Since ->get_mem_map() () may indicate that not all of a RC PCI > address region can be mapped, 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 > by repeatedly using pci_epc_mem_map() over the desried PCI address > range. > > The counterpart of pci_epc_mem_map() to unmap and free the controller > memory address region is pci_epc_mem_unmap(). > > Both functions as well as the ->get_mem_map() controller operation > operate using the new struct pci_epc_map data structure. This new > structure represents a mapping PCI address, mapping effective size, the > size and offset into the controller memory needed for the mapping 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). > > 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 > Signed-off-by: Rick Wertenbroek > Signed-off-by: Damien Le Moal > --- > drivers/pci/endpoint/pci-epc-core.c | 126 ++++++++++++++++++++++++++++ > include/linux/pci-epc.h | 39 +++++++++ > 2 files changed, 165 insertions(+) > > diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c > index b854f1bab26f..b6bf6d9f9f85 100644 > --- a/drivers/pci/endpoint/pci-epc-core.c > +++ b/drivers/pci/endpoint/pci-epc-core.c > @@ -466,6 +466,132 @@ int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no, > } > EXPORT_SYMBOL_GPL(pci_epc_map_addr); > > +/* > + * Determine the actual PCI address range that should be mapped to access > + * @pci_size from @pci_addr. This is done using the controller get_mem_map > + * operation if that operation is defined. Otherwise, simply assume that the > + * controller has no mapping alignment constraint and return the requested range > + * as-is. > + */ > +static int pci_epc_get_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; > + > + /* > + * Initialize and remember the PCI address region to be mapped. The > + * controller ->get_mem_map() operation may change the map->pci_size to a > + * smaller value. > + */ > + memset(map, 0, sizeof(*map)); > + map->pci_addr = pci_addr; > + map->pci_size = pci_size; > + > + if (!epc->ops->get_mem_map) { > + /* > + * Assume that the EP controller has no alignment constraint, > + * that is, that the PCI address to map and the size of the > + * controller memory needed for the mapping are the same as > + * specified by the caller. > + */ > + map->map_pci_addr = pci_addr; > + map->map_size = pci_size; > + map->map_ofst = 0; > + return 0; > + } > + > + mutex_lock(&epc->lock); > + ret = epc->ops->get_mem_map(epc, func_no, vfunc_no, map); > + mutex_unlock(&epc->lock); > + > + return ret; > +} > + > +/** > + * 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_get_mem_map(). > + * 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; > + > + if (!pci_epc_function_is_valid(epc, func_no, vfunc_no)) > + return -EINVAL; > + > + if (!pci_size || !map) > + return -EINVAL; > + > + ret = pci_epc_get_mem_map(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; As reported by the kernel test robot on both v3 and v4, this should be: map->virt_base = NULL; otherwise you introduce a new sparse warning. > + 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); > +} > +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 42ef06136bd1..b5f5c1eb54c5 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 > + * @get_mem_map: 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 (*get_mem_map)(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, > @@ -278,6 +313,10 @@ 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) > -- > 2.47.0 >