diff options
Diffstat (limited to 'drivers/vdpa/solidrun/snet_ctrl.c')
-rw-r--r-- | drivers/vdpa/solidrun/snet_ctrl.c | 336 |
1 files changed, 336 insertions, 0 deletions
diff --git a/drivers/vdpa/solidrun/snet_ctrl.c b/drivers/vdpa/solidrun/snet_ctrl.c new file mode 100644 index 0000000000..3cef2571d1 --- /dev/null +++ b/drivers/vdpa/solidrun/snet_ctrl.c @@ -0,0 +1,336 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * SolidRun DPU driver for control plane + * + * Copyright (C) 2022-2023 SolidRun + * + * Author: Alvaro Karsz <alvaro.karsz@solid-run.com> + * + */ + +#include <linux/iopoll.h> + +#include "snet_vdpa.h" + +enum snet_ctrl_opcodes { + SNET_CTRL_OP_DESTROY = 1, + SNET_CTRL_OP_READ_VQ_STATE, + SNET_CTRL_OP_SUSPEND, + SNET_CTRL_OP_RESUME, +}; + +#define SNET_CTRL_TIMEOUT 2000000 + +#define SNET_CTRL_DATA_SIZE_MASK 0x0000FFFF +#define SNET_CTRL_IN_PROCESS_MASK 0x00010000 +#define SNET_CTRL_CHUNK_RDY_MASK 0x00020000 +#define SNET_CTRL_ERROR_MASK 0x0FFC0000 + +#define SNET_VAL_TO_ERR(val) (-(((val) & SNET_CTRL_ERROR_MASK) >> 18)) +#define SNET_EMPTY_CTRL(val) (((val) & SNET_CTRL_ERROR_MASK) || \ + !((val) & SNET_CTRL_IN_PROCESS_MASK)) +#define SNET_DATA_READY(val) ((val) & (SNET_CTRL_ERROR_MASK | SNET_CTRL_CHUNK_RDY_MASK)) + +/* Control register used to read data from the DPU */ +struct snet_ctrl_reg_ctrl { + /* Chunk size in 4B words */ + u16 data_size; + /* We are in the middle of a command */ + u16 in_process:1; + /* A data chunk is ready and can be consumed */ + u16 chunk_ready:1; + /* Error code */ + u16 error:10; + /* Saved for future usage */ + u16 rsvd:4; +}; + +/* Opcode register */ +struct snet_ctrl_reg_op { + u16 opcode; + /* Only if VQ index is relevant for the command */ + u16 vq_idx; +}; + +struct snet_ctrl_regs { + struct snet_ctrl_reg_op op; + struct snet_ctrl_reg_ctrl ctrl; + u32 rsvd; + u32 data[]; +}; + +static struct snet_ctrl_regs __iomem *snet_get_ctrl(struct snet *snet) +{ + return snet->bar + snet->psnet->cfg.ctrl_off; +} + +static int snet_wait_for_empty_ctrl(struct snet_ctrl_regs __iomem *regs) +{ + u32 val; + + return readx_poll_timeout(ioread32, ®s->ctrl, val, SNET_EMPTY_CTRL(val), 10, + SNET_CTRL_TIMEOUT); +} + +static int snet_wait_for_empty_op(struct snet_ctrl_regs __iomem *regs) +{ + u32 val; + + return readx_poll_timeout(ioread32, ®s->op, val, !val, 10, SNET_CTRL_TIMEOUT); +} + +static int snet_wait_for_data(struct snet_ctrl_regs __iomem *regs) +{ + u32 val; + + return readx_poll_timeout(ioread32, ®s->ctrl, val, SNET_DATA_READY(val), 10, + SNET_CTRL_TIMEOUT); +} + +static u32 snet_read32_word(struct snet_ctrl_regs __iomem *ctrl_regs, u16 word_idx) +{ + return ioread32(&ctrl_regs->data[word_idx]); +} + +static u32 snet_read_ctrl(struct snet_ctrl_regs __iomem *ctrl_regs) +{ + return ioread32(&ctrl_regs->ctrl); +} + +static void snet_write_ctrl(struct snet_ctrl_regs __iomem *ctrl_regs, u32 val) +{ + iowrite32(val, &ctrl_regs->ctrl); +} + +static void snet_write_op(struct snet_ctrl_regs __iomem *ctrl_regs, u32 val) +{ + iowrite32(val, &ctrl_regs->op); +} + +static int snet_wait_for_dpu_completion(struct snet_ctrl_regs __iomem *ctrl_regs) +{ + /* Wait until the DPU finishes completely. + * It will clear the opcode register. + */ + return snet_wait_for_empty_op(ctrl_regs); +} + +/* Reading ctrl from the DPU: + * buf_size must be 4B aligned + * + * Steps: + * + * (1) Verify that the DPU is not in the middle of another operation by + * reading the in_process and error bits in the control register. + * (2) Write the request opcode and the VQ idx in the opcode register + * and write the buffer size in the control register. + * (3) Start readind chunks of data, chunk_ready bit indicates that a + * data chunk is available, we signal that we read the data by clearing the bit. + * (4) Detect that the transfer is completed when the in_process bit + * in the control register is cleared or when the an error appears. + */ +static int snet_ctrl_read_from_dpu(struct snet *snet, u16 opcode, u16 vq_idx, void *buffer, + u32 buf_size) +{ + struct pci_dev *pdev = snet->pdev; + struct snet_ctrl_regs __iomem *regs = snet_get_ctrl(snet); + u32 *bfr_ptr = (u32 *)buffer; + u32 val; + u16 buf_words; + int ret; + u16 words, i, tot_words = 0; + + /* Supported for config 2+ */ + if (!SNET_CFG_VER(snet, 2)) + return -EOPNOTSUPP; + + if (!IS_ALIGNED(buf_size, 4)) + return -EINVAL; + + mutex_lock(&snet->ctrl_lock); + + buf_words = buf_size / 4; + + /* Make sure control register is empty */ + ret = snet_wait_for_empty_ctrl(regs); + if (ret) { + SNET_WARN(pdev, "Timeout waiting for previous control data to be consumed\n"); + goto exit; + } + + /* We need to write the buffer size in the control register, and the opcode + vq index in + * the opcode register. + * We use a spinlock to serialize the writes. + */ + spin_lock(&snet->ctrl_spinlock); + + snet_write_ctrl(regs, buf_words); + snet_write_op(regs, opcode | (vq_idx << 16)); + + spin_unlock(&snet->ctrl_spinlock); + + while (buf_words != tot_words) { + ret = snet_wait_for_data(regs); + if (ret) { + SNET_WARN(pdev, "Timeout waiting for control data\n"); + goto exit; + } + + val = snet_read_ctrl(regs); + + /* Error? */ + if (val & SNET_CTRL_ERROR_MASK) { + ret = SNET_VAL_TO_ERR(val); + SNET_WARN(pdev, "Error while reading control data from DPU, err %d\n", ret); + goto exit; + } + + words = min_t(u16, val & SNET_CTRL_DATA_SIZE_MASK, buf_words - tot_words); + + for (i = 0; i < words; i++) { + *bfr_ptr = snet_read32_word(regs, i); + bfr_ptr++; + } + + tot_words += words; + + /* Is the job completed? */ + if (!(val & SNET_CTRL_IN_PROCESS_MASK)) + break; + + /* Clear the chunk ready bit and continue */ + val &= ~SNET_CTRL_CHUNK_RDY_MASK; + snet_write_ctrl(regs, val); + } + + ret = snet_wait_for_dpu_completion(regs); + if (ret) + SNET_WARN(pdev, "Timeout waiting for the DPU to complete a control command\n"); + +exit: + mutex_unlock(&snet->ctrl_lock); + return ret; +} + +/* Send a control message to the DPU using the old mechanism + * used with config version 1. + */ +static int snet_send_ctrl_msg_old(struct snet *snet, u32 opcode) +{ + struct pci_dev *pdev = snet->pdev; + struct snet_ctrl_regs __iomem *regs = snet_get_ctrl(snet); + int ret; + + mutex_lock(&snet->ctrl_lock); + + /* Old mechanism uses just 1 register, the opcode register. + * Make sure that the opcode register is empty, and that the DPU isn't + * processing an old message. + */ + ret = snet_wait_for_empty_op(regs); + if (ret) { + SNET_WARN(pdev, "Timeout waiting for previous control message to be ACKed\n"); + goto exit; + } + + /* Write the message */ + snet_write_op(regs, opcode); + + /* DPU ACKs the message by clearing the opcode register */ + ret = snet_wait_for_empty_op(regs); + if (ret) + SNET_WARN(pdev, "Timeout waiting for a control message to be ACKed\n"); + +exit: + mutex_unlock(&snet->ctrl_lock); + return ret; +} + +/* Send a control message to the DPU. + * A control message is a message without payload. + */ +static int snet_send_ctrl_msg(struct snet *snet, u16 opcode, u16 vq_idx) +{ + struct pci_dev *pdev = snet->pdev; + struct snet_ctrl_regs __iomem *regs = snet_get_ctrl(snet); + u32 val; + int ret; + + /* If config version is not 2+, use the old mechanism */ + if (!SNET_CFG_VER(snet, 2)) + return snet_send_ctrl_msg_old(snet, opcode); + + mutex_lock(&snet->ctrl_lock); + + /* Make sure control register is empty */ + ret = snet_wait_for_empty_ctrl(regs); + if (ret) { + SNET_WARN(pdev, "Timeout waiting for previous control data to be consumed\n"); + goto exit; + } + + /* We need to clear the control register and write the opcode + vq index in the opcode + * register. + * We use a spinlock to serialize the writes. + */ + spin_lock(&snet->ctrl_spinlock); + + snet_write_ctrl(regs, 0); + snet_write_op(regs, opcode | (vq_idx << 16)); + + spin_unlock(&snet->ctrl_spinlock); + + /* The DPU ACKs control messages by setting the chunk ready bit + * without data. + */ + ret = snet_wait_for_data(regs); + if (ret) { + SNET_WARN(pdev, "Timeout waiting for control message to be ACKed\n"); + goto exit; + } + + /* Check for errors */ + val = snet_read_ctrl(regs); + ret = SNET_VAL_TO_ERR(val); + + /* Clear the chunk ready bit */ + val &= ~SNET_CTRL_CHUNK_RDY_MASK; + snet_write_ctrl(regs, val); + + ret = snet_wait_for_dpu_completion(regs); + if (ret) + SNET_WARN(pdev, "Timeout waiting for DPU to complete a control command, err %d\n", + ret); + +exit: + mutex_unlock(&snet->ctrl_lock); + return ret; +} + +void snet_ctrl_clear(struct snet *snet) +{ + struct snet_ctrl_regs __iomem *regs = snet_get_ctrl(snet); + + snet_write_op(regs, 0); +} + +int snet_destroy_dev(struct snet *snet) +{ + return snet_send_ctrl_msg(snet, SNET_CTRL_OP_DESTROY, 0); +} + +int snet_read_vq_state(struct snet *snet, u16 idx, struct vdpa_vq_state *state) +{ + return snet_ctrl_read_from_dpu(snet, SNET_CTRL_OP_READ_VQ_STATE, idx, state, + sizeof(*state)); +} + +int snet_suspend_dev(struct snet *snet) +{ + return snet_send_ctrl_msg(snet, SNET_CTRL_OP_SUSPEND, 0); +} + +int snet_resume_dev(struct snet *snet) +{ + return snet_send_ctrl_msg(snet, SNET_CTRL_OP_RESUME, 0); +} |