diff options
Diffstat (limited to 'drivers/net/ethernet/microsoft/mana/shm_channel.c')
| -rw-r--r-- | drivers/net/ethernet/microsoft/mana/shm_channel.c | 291 |
1 files changed, 291 insertions, 0 deletions
diff --git a/drivers/net/ethernet/microsoft/mana/shm_channel.c b/drivers/net/ethernet/microsoft/mana/shm_channel.c new file mode 100644 index 000000000..da255da62 --- /dev/null +++ b/drivers/net/ethernet/microsoft/mana/shm_channel.c @@ -0,0 +1,291 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause +/* Copyright (c) 2021, Microsoft Corporation. */ + +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/io.h> +#include <linux/mm.h> + +#include "shm_channel.h" + +#define PAGE_FRAME_L48_WIDTH_BYTES 6 +#define PAGE_FRAME_L48_WIDTH_BITS (PAGE_FRAME_L48_WIDTH_BYTES * 8) +#define PAGE_FRAME_L48_MASK 0x0000FFFFFFFFFFFF +#define PAGE_FRAME_H4_WIDTH_BITS 4 +#define VECTOR_MASK 0xFFFF +#define SHMEM_VF_RESET_STATE ((u32)-1) + +#define SMC_MSG_TYPE_ESTABLISH_HWC 1 +#define SMC_MSG_TYPE_ESTABLISH_HWC_VERSION 0 + +#define SMC_MSG_TYPE_DESTROY_HWC 2 +#define SMC_MSG_TYPE_DESTROY_HWC_VERSION 0 + +#define SMC_MSG_DIRECTION_REQUEST 0 +#define SMC_MSG_DIRECTION_RESPONSE 1 + +/* Structures labeled with "HW DATA" are exchanged with the hardware. All of + * them are naturally aligned and hence don't need __packed. + */ + +/* Shared memory channel protocol header + * + * msg_type: set on request and response; response matches request. + * msg_version: newer PF writes back older response (matching request) + * older PF acts on latest version known and sets that version in result + * (less than request). + * direction: 0 for request, VF->PF; 1 for response, PF->VF. + * status: 0 on request, + * operation result on response (success = 0, failure = 1 or greater). + * reset_vf: If set on either establish or destroy request, indicates perform + * FLR before/after the operation. + * owner_is_pf: 1 indicates PF owned, 0 indicates VF owned. + */ +union smc_proto_hdr { + u32 as_uint32; + + struct { + u8 msg_type : 3; + u8 msg_version : 3; + u8 reserved_1 : 1; + u8 direction : 1; + + u8 status; + + u8 reserved_2; + + u8 reset_vf : 1; + u8 reserved_3 : 6; + u8 owner_is_pf : 1; + }; +}; /* HW DATA */ + +#define SMC_APERTURE_BITS 256 +#define SMC_BASIC_UNIT (sizeof(u32)) +#define SMC_APERTURE_DWORDS (SMC_APERTURE_BITS / (SMC_BASIC_UNIT * 8)) +#define SMC_LAST_DWORD (SMC_APERTURE_DWORDS - 1) + +static int mana_smc_poll_register(void __iomem *base, bool reset) +{ + void __iomem *ptr = base + SMC_LAST_DWORD * SMC_BASIC_UNIT; + u32 last_dword; + int i; + + /* Poll the hardware for the ownership bit. This should be pretty fast, + * but let's do it in a loop just in case the hardware or the PF + * driver are temporarily busy. + */ + for (i = 0; i < 20 * 1000; i++) { + last_dword = readl(ptr); + + /* shmem reads as 0xFFFFFFFF in the reset case */ + if (reset && last_dword == SHMEM_VF_RESET_STATE) + return 0; + + /* If bit_31 is set, the PF currently owns the SMC. */ + if (!(last_dword & BIT(31))) + return 0; + + usleep_range(1000, 2000); + } + + return -ETIMEDOUT; +} + +static int mana_smc_read_response(struct shm_channel *sc, u32 msg_type, + u32 msg_version, bool reset_vf) +{ + void __iomem *base = sc->base; + union smc_proto_hdr hdr; + int err; + + /* Wait for PF to respond. */ + err = mana_smc_poll_register(base, reset_vf); + if (err) + return err; + + hdr.as_uint32 = readl(base + SMC_LAST_DWORD * SMC_BASIC_UNIT); + + if (reset_vf && hdr.as_uint32 == SHMEM_VF_RESET_STATE) + return 0; + + /* Validate protocol fields from the PF driver */ + if (hdr.msg_type != msg_type || hdr.msg_version > msg_version || + hdr.direction != SMC_MSG_DIRECTION_RESPONSE) { + dev_err(sc->dev, "Wrong SMC response 0x%x, type=%d, ver=%d\n", + hdr.as_uint32, msg_type, msg_version); + return -EPROTO; + } + + /* Validate the operation result */ + if (hdr.status != 0) { + dev_err(sc->dev, "SMC operation failed: 0x%x\n", hdr.status); + return -EPROTO; + } + + return 0; +} + +void mana_smc_init(struct shm_channel *sc, struct device *dev, + void __iomem *base) +{ + sc->dev = dev; + sc->base = base; +} + +int mana_smc_setup_hwc(struct shm_channel *sc, bool reset_vf, u64 eq_addr, + u64 cq_addr, u64 rq_addr, u64 sq_addr, + u32 eq_msix_index) +{ + union smc_proto_hdr *hdr; + u16 all_addr_h4bits = 0; + u16 frame_addr_seq = 0; + u64 frame_addr = 0; + u8 shm_buf[32]; + u64 *shmem; + u32 *dword; + u8 *ptr; + int err; + int i; + + /* Ensure VF already has possession of shared memory */ + err = mana_smc_poll_register(sc->base, false); + if (err) { + dev_err(sc->dev, "Timeout when setting up HWC: %d\n", err); + return err; + } + + if (!PAGE_ALIGNED(eq_addr) || !PAGE_ALIGNED(cq_addr) || + !PAGE_ALIGNED(rq_addr) || !PAGE_ALIGNED(sq_addr)) + return -EINVAL; + + if ((eq_msix_index & VECTOR_MASK) != eq_msix_index) + return -EINVAL; + + /* Scheme for packing four addresses and extra info into 256 bits. + * + * Addresses must be page frame aligned, so only frame address bits + * are transferred. + * + * 52-bit frame addresses are split into the lower 48 bits and upper + * 4 bits. Lower 48 bits of 4 address are written sequentially from + * the start of the 256-bit shared memory region followed by 16 bits + * containing the upper 4 bits of the 4 addresses in sequence. + * + * A 16 bit EQ vector number fills out the next-to-last 32-bit dword. + * + * The final 32-bit dword is used for protocol control information as + * defined in smc_proto_hdr. + */ + + memset(shm_buf, 0, sizeof(shm_buf)); + ptr = shm_buf; + + /* EQ addr: low 48 bits of frame address */ + shmem = (u64 *)ptr; + frame_addr = PHYS_PFN(eq_addr); + *shmem = frame_addr & PAGE_FRAME_L48_MASK; + all_addr_h4bits |= (frame_addr >> PAGE_FRAME_L48_WIDTH_BITS) << + (frame_addr_seq++ * PAGE_FRAME_H4_WIDTH_BITS); + ptr += PAGE_FRAME_L48_WIDTH_BYTES; + + /* CQ addr: low 48 bits of frame address */ + shmem = (u64 *)ptr; + frame_addr = PHYS_PFN(cq_addr); + *shmem = frame_addr & PAGE_FRAME_L48_MASK; + all_addr_h4bits |= (frame_addr >> PAGE_FRAME_L48_WIDTH_BITS) << + (frame_addr_seq++ * PAGE_FRAME_H4_WIDTH_BITS); + ptr += PAGE_FRAME_L48_WIDTH_BYTES; + + /* RQ addr: low 48 bits of frame address */ + shmem = (u64 *)ptr; + frame_addr = PHYS_PFN(rq_addr); + *shmem = frame_addr & PAGE_FRAME_L48_MASK; + all_addr_h4bits |= (frame_addr >> PAGE_FRAME_L48_WIDTH_BITS) << + (frame_addr_seq++ * PAGE_FRAME_H4_WIDTH_BITS); + ptr += PAGE_FRAME_L48_WIDTH_BYTES; + + /* SQ addr: low 48 bits of frame address */ + shmem = (u64 *)ptr; + frame_addr = PHYS_PFN(sq_addr); + *shmem = frame_addr & PAGE_FRAME_L48_MASK; + all_addr_h4bits |= (frame_addr >> PAGE_FRAME_L48_WIDTH_BITS) << + (frame_addr_seq++ * PAGE_FRAME_H4_WIDTH_BITS); + ptr += PAGE_FRAME_L48_WIDTH_BYTES; + + /* High 4 bits of the four frame addresses */ + *((u16 *)ptr) = all_addr_h4bits; + ptr += sizeof(u16); + + /* EQ MSIX vector number */ + *((u16 *)ptr) = (u16)eq_msix_index; + ptr += sizeof(u16); + + /* 32-bit protocol header in final dword */ + *((u32 *)ptr) = 0; + + hdr = (union smc_proto_hdr *)ptr; + hdr->msg_type = SMC_MSG_TYPE_ESTABLISH_HWC; + hdr->msg_version = SMC_MSG_TYPE_ESTABLISH_HWC_VERSION; + hdr->direction = SMC_MSG_DIRECTION_REQUEST; + hdr->reset_vf = reset_vf; + + /* Write 256-message buffer to shared memory (final 32-bit write + * triggers HW to set possession bit to PF). + */ + dword = (u32 *)shm_buf; + for (i = 0; i < SMC_APERTURE_DWORDS; i++) + writel(*dword++, sc->base + i * SMC_BASIC_UNIT); + + /* Read shmem response (polling for VF possession) and validate. + * For setup, waiting for response on shared memory is not strictly + * necessary, since wait occurs later for results to appear in EQE's. + */ + err = mana_smc_read_response(sc, SMC_MSG_TYPE_ESTABLISH_HWC, + SMC_MSG_TYPE_ESTABLISH_HWC_VERSION, + reset_vf); + if (err) { + dev_err(sc->dev, "Error when setting up HWC: %d\n", err); + return err; + } + + return 0; +} + +int mana_smc_teardown_hwc(struct shm_channel *sc, bool reset_vf) +{ + union smc_proto_hdr hdr = {}; + int err; + + /* Ensure already has possession of shared memory */ + err = mana_smc_poll_register(sc->base, false); + if (err) { + dev_err(sc->dev, "Timeout when tearing down HWC\n"); + return err; + } + + /* Set up protocol header for HWC destroy message */ + hdr.msg_type = SMC_MSG_TYPE_DESTROY_HWC; + hdr.msg_version = SMC_MSG_TYPE_DESTROY_HWC_VERSION; + hdr.direction = SMC_MSG_DIRECTION_REQUEST; + hdr.reset_vf = reset_vf; + + /* Write message in high 32 bits of 256-bit shared memory, causing HW + * to set possession bit to PF. + */ + writel(hdr.as_uint32, sc->base + SMC_LAST_DWORD * SMC_BASIC_UNIT); + + /* Read shmem response (polling for VF possession) and validate. + * For teardown, waiting for response is required to ensure hardware + * invalidates MST entries before software frees memory. + */ + err = mana_smc_read_response(sc, SMC_MSG_TYPE_DESTROY_HWC, + SMC_MSG_TYPE_DESTROY_HWC_VERSION, + reset_vf); + if (err) { + dev_err(sc->dev, "Error when tearing down HWC: %d\n", err); + return err; + } + + return 0; +} |