From fa41d10589be124404492b5181a818a509d8cb1c Mon Sep 17 00:00:00 2001 From: Matthew Gerlach Date: Wed, 6 Jan 2021 20:37:08 -0800 Subject: fpga: dfl-pci: locate DFLs by PCIe vendor specific capability A PCIe vendor specific extended capability is introduced by Intel to specify the start of a number of DFLs. Signed-off-by: Matthew Gerlach Signed-off-by: Moritz Fischer Link: https://lore.kernel.org/r/20210107043714.991646-3-mdf@kernel.org Signed-off-by: Greg Kroah-Hartman --- Documentation/fpga/dfl.rst | 27 ++++++++++++++ drivers/fpga/dfl-pci.c | 87 +++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 113 insertions(+), 1 deletion(-) diff --git a/Documentation/fpga/dfl.rst b/Documentation/fpga/dfl.rst index 0404fe6ffc74..ea8cefc18bdb 100644 --- a/Documentation/fpga/dfl.rst +++ b/Documentation/fpga/dfl.rst @@ -501,6 +501,33 @@ Developer only needs to provide a sub feature driver with matched feature id. FME Partial Reconfiguration Sub Feature driver (see drivers/fpga/dfl-fme-pr.c) could be a reference. +Location of DFLs on a PCI Device +=========================== +The original method for finding a DFL on a PCI device assumed the start of the +first DFL to offset 0 of bar 0. If the first node of the DFL is an FME, +then further DFLs in the port(s) are specified in FME header registers. +Alternatively, a PCIe vendor specific capability structure can be used to +specify the location of all the DFLs on the device, providing flexibility +for the type of starting node in the DFL. Intel has reserved the +VSEC ID of 0x43 for this purpose. The vendor specific +data begins with a 4 byte vendor specific register for the number of DFLs followed 4 byte +Offset/BIR vendor specific registers for each DFL. Bits 2:0 of Offset/BIR register +indicates the BAR, and bits 31:3 form the 8 byte aligned offset where bits 2:0 are +zero. + + +----------------------------+ + |31 Number of DFLS 0| + +----------------------------+ + |31 Offset 3|2 BIR 0| + +----------------------------+ + . . . + +----------------------------+ + |31 Offset 3|2 BIR 0| + +----------------------------+ + +Being able to specify more than one DFL per BAR has been considered, but it +was determined the use case did not provide value. Specifying a single DFL +per BAR simplifies the implementation and allows for extra error checking. Open discussion =============== diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c index 5100695e27cd..04e47e266f26 100644 --- a/drivers/fpga/dfl-pci.c +++ b/drivers/fpga/dfl-pci.c @@ -27,6 +27,14 @@ #define DRV_VERSION "0.8" #define DRV_NAME "dfl-pci" +#define PCI_VSEC_ID_INTEL_DFLS 0x43 + +#define PCI_VNDR_DFLS_CNT 0x8 +#define PCI_VNDR_DFLS_RES 0xc + +#define PCI_VNDR_DFLS_RES_BAR_MASK GENMASK(2, 0) +#define PCI_VNDR_DFLS_RES_OFF_MASK GENMASK(31, 3) + struct cci_drvdata { struct dfl_fpga_cdev *cdev; /* container device */ }; @@ -119,6 +127,80 @@ static int *cci_pci_create_irq_table(struct pci_dev *pcidev, unsigned int nvec) return table; } +static int find_dfls_by_vsec(struct pci_dev *pcidev, struct dfl_fpga_enum_info *info) +{ + u32 bir, offset, vndr_hdr, dfl_cnt, dfl_res; + int dfl_res_off, i, bars, voff = 0; + resource_size_t start, len; + + while ((voff = pci_find_next_ext_capability(pcidev, voff, PCI_EXT_CAP_ID_VNDR))) { + vndr_hdr = 0; + pci_read_config_dword(pcidev, voff + PCI_VNDR_HEADER, &vndr_hdr); + + if (PCI_VNDR_HEADER_ID(vndr_hdr) == PCI_VSEC_ID_INTEL_DFLS && + pcidev->vendor == PCI_VENDOR_ID_INTEL) + break; + } + + if (!voff) { + dev_dbg(&pcidev->dev, "%s no DFL VSEC found\n", __func__); + return -ENODEV; + } + + dfl_cnt = 0; + pci_read_config_dword(pcidev, voff + PCI_VNDR_DFLS_CNT, &dfl_cnt); + if (dfl_cnt > PCI_STD_NUM_BARS) { + dev_err(&pcidev->dev, "%s too many DFLs %d > %d\n", + __func__, dfl_cnt, PCI_STD_NUM_BARS); + return -EINVAL; + } + + dfl_res_off = voff + PCI_VNDR_DFLS_RES; + if (dfl_res_off + (dfl_cnt * sizeof(u32)) > PCI_CFG_SPACE_EXP_SIZE) { + dev_err(&pcidev->dev, "%s DFL VSEC too big for PCIe config space\n", + __func__); + return -EINVAL; + } + + for (i = 0, bars = 0; i < dfl_cnt; i++, dfl_res_off += sizeof(u32)) { + dfl_res = GENMASK(31, 0); + pci_read_config_dword(pcidev, dfl_res_off, &dfl_res); + + bir = dfl_res & PCI_VNDR_DFLS_RES_BAR_MASK; + if (bir >= PCI_STD_NUM_BARS) { + dev_err(&pcidev->dev, "%s bad bir number %d\n", + __func__, bir); + return -EINVAL; + } + + if (bars & BIT(bir)) { + dev_err(&pcidev->dev, "%s DFL for BAR %d already specified\n", + __func__, bir); + return -EINVAL; + } + + bars |= BIT(bir); + + len = pci_resource_len(pcidev, bir); + offset = dfl_res & PCI_VNDR_DFLS_RES_OFF_MASK; + if (offset >= len) { + dev_err(&pcidev->dev, "%s bad offset %u >= %pa\n", + __func__, offset, &len); + return -EINVAL; + } + + dev_dbg(&pcidev->dev, "%s BAR %d offset 0x%x\n", __func__, bir, offset); + + len -= offset; + + start = pci_resource_start(pcidev, bir) + offset; + + dfl_fpga_enum_info_add_dfl(info, start, len); + } + + return 0; +} + /* default method of finding dfls starting at offset 0 of bar 0 */ static int find_dfls_by_default(struct pci_dev *pcidev, struct dfl_fpga_enum_info *info) @@ -220,7 +302,10 @@ static int cci_enumerate_feature_devs(struct pci_dev *pcidev) goto irq_free_exit; } - ret = find_dfls_by_default(pcidev, info); + ret = find_dfls_by_vsec(pcidev, info); + if (ret == -ENODEV) + ret = find_dfls_by_default(pcidev, info); + if (ret) goto irq_free_exit; -- cgit v1.2.3