// SPDX-License-Identifier: GPL-2.0-only
#include <stdint.h>
#include <unistd.h>

#include <linux/bits.h>
#include <linux/errno.h>
#include <linux/idxd.h>
#include <linux/io.h>
#include <linux/pci_ids.h>
#include <linux/sizes.h>

#include <vfio_util.h>

#include "registers.h"

/* Vectors 1+ are available for work queue completion interrupts. */
#define MSIX_VECTOR 1

struct dsa_state {
	/* Descriptors for copy and batch operations. */
	struct dsa_hw_desc batch[32];
	struct dsa_hw_desc copy[1024];

	/* Completion records for copy and batch operations. */
	struct dsa_completion_record copy_completion;
	struct dsa_completion_record batch_completion;

	/* Cached device registers (and derived data) for easy access */
	union gen_cap_reg gen_cap;
	union wq_cap_reg wq_cap;
	union group_cap_reg group_cap;
	union engine_cap_reg engine_cap;
	union offsets_reg table_offsets;
	void *wqcfg_table;
	void *grpcfg_table;
	u64 max_batches;
	u64 max_copies_per_batch;

	/* The number of ongoing memcpy operations. */
	u64 memcpy_count;

	/* Buffers used by dsa_send_msi() to generate an interrupt */
	u64 send_msi_src;
	u64 send_msi_dst;
};

static inline struct dsa_state *to_dsa_state(struct vfio_pci_device *device)
{
	return device->driver.region.vaddr;
}

static bool dsa_int_handle_request_required(struct vfio_pci_device *device)
{
	void *bar0 = device->bars[0].vaddr;
	union gen_cap_reg gen_cap;
	u32 cmd_cap;

	gen_cap.bits = readq(bar0 + IDXD_GENCAP_OFFSET);
	if (!gen_cap.cmd_cap)
		return false;

	cmd_cap = readl(bar0 + IDXD_CMDCAP_OFFSET);
	return (cmd_cap >> IDXD_CMD_REQUEST_INT_HANDLE) & 1;
}

static int dsa_probe(struct vfio_pci_device *device)
{
	if (!vfio_pci_device_match(device, PCI_VENDOR_ID_INTEL,
				   PCI_DEVICE_ID_INTEL_DSA_SPR0))
		return -EINVAL;

	if (dsa_int_handle_request_required(device)) {
		printf("Device requires requesting interrupt handles\n");
		return -EINVAL;
	}

	return 0;
}

static void dsa_check_sw_err(struct vfio_pci_device *device)
{
	void *reg = device->bars[0].vaddr + IDXD_SWERR_OFFSET;
	union sw_err_reg err = {};
	int i;

	for (i = 0; i < ARRAY_SIZE(err.bits); i++) {
		err.bits[i] = readq(reg + offsetof(union sw_err_reg, bits[i]));

		/* No errors */
		if (i == 0 && !err.valid)
			return;
	}

	fprintf(stderr, "SWERR: 0x%016lx 0x%016lx 0x%016lx 0x%016lx\n",
		err.bits[0], err.bits[1], err.bits[2], err.bits[3]);

	fprintf(stderr, "  valid: 0x%x\n", err.valid);
	fprintf(stderr, "  overflow: 0x%x\n", err.overflow);
	fprintf(stderr, "  desc_valid: 0x%x\n", err.desc_valid);
	fprintf(stderr, "  wq_idx_valid: 0x%x\n", err.wq_idx_valid);
	fprintf(stderr, "  batch: 0x%x\n", err.batch);
	fprintf(stderr, "  fault_rw: 0x%x\n", err.fault_rw);
	fprintf(stderr, "  priv: 0x%x\n", err.priv);
	fprintf(stderr, "  error: 0x%x\n", err.error);
	fprintf(stderr, "  wq_idx: 0x%x\n", err.wq_idx);
	fprintf(stderr, "  operation: 0x%x\n", err.operation);
	fprintf(stderr, "  pasid: 0x%x\n", err.pasid);
	fprintf(stderr, "  batch_idx: 0x%x\n", err.batch_idx);
	fprintf(stderr, "  invalid_flags: 0x%x\n", err.invalid_flags);
	fprintf(stderr, "  fault_addr: 0x%lx\n", err.fault_addr);

	VFIO_FAIL("Software Error Detected!\n");
}

static void dsa_command(struct vfio_pci_device *device, u32 cmd)
{
	union idxd_command_reg cmd_reg = { .cmd = cmd };
	u32 sleep_ms = 1, attempts = 5000 / sleep_ms;
	void *bar0 = device->bars[0].vaddr;
	u32 status;
	u8 err;

	writel(cmd_reg.bits, bar0 + IDXD_CMD_OFFSET);

	for (;;) {
		dsa_check_sw_err(device);

		status = readl(bar0 + IDXD_CMDSTS_OFFSET);
		if (!(status & IDXD_CMDSTS_ACTIVE))
			break;

		VFIO_ASSERT_GT(--attempts, 0);
		usleep(sleep_ms * 1000);
	}

	err = status & IDXD_CMDSTS_ERR_MASK;
	VFIO_ASSERT_EQ(err, 0, "Error issuing command 0x%x: 0x%x\n", cmd, err);
}

static void dsa_wq_init(struct vfio_pci_device *device)
{
	struct dsa_state *dsa = to_dsa_state(device);
	union wq_cap_reg wq_cap = dsa->wq_cap;
	union wqcfg wqcfg;
	u64 wqcfg_size;
	int i;

	VFIO_ASSERT_GT((u32)wq_cap.num_wqs, 0);

	wqcfg = (union wqcfg) {
		.wq_size = wq_cap.total_wq_size,
		.mode = 1,
		.priority = 1,
		/*
		 * Disable Address Translation Service (if enabled) so that VFIO
		 * selftests using this driver can generate I/O page faults.
		 */
		.wq_ats_disable = wq_cap.wq_ats_support,
		.max_xfer_shift = dsa->gen_cap.max_xfer_shift,
		.max_batch_shift = dsa->gen_cap.max_batch_shift,
		.op_config[0] = BIT(DSA_OPCODE_MEMMOVE) | BIT(DSA_OPCODE_BATCH),
	};

	wqcfg_size = 1UL << (wq_cap.wqcfg_size + IDXD_WQCFG_MIN);

	for (i = 0; i < wqcfg_size / sizeof(wqcfg.bits[0]); i++)
		writel(wqcfg.bits[i], dsa->wqcfg_table + offsetof(union wqcfg, bits[i]));
}

static void dsa_group_init(struct vfio_pci_device *device)
{
	struct dsa_state *dsa = to_dsa_state(device);
	union group_cap_reg group_cap = dsa->group_cap;
	union engine_cap_reg engine_cap = dsa->engine_cap;

	VFIO_ASSERT_GT((u32)group_cap.num_groups, 0);
	VFIO_ASSERT_GT((u32)engine_cap.num_engines, 0);

	/* Assign work queue 0 and engine 0 to group 0 */
	writeq(1, dsa->grpcfg_table + offsetof(struct grpcfg, wqs[0]));
	writeq(1, dsa->grpcfg_table + offsetof(struct grpcfg, engines));
}

static void dsa_register_cache_init(struct vfio_pci_device *device)
{
	struct dsa_state *dsa = to_dsa_state(device);
	void *bar0 = device->bars[0].vaddr;

	dsa->gen_cap.bits = readq(bar0 + IDXD_GENCAP_OFFSET);
	dsa->wq_cap.bits = readq(bar0 + IDXD_WQCAP_OFFSET);
	dsa->group_cap.bits = readq(bar0 + IDXD_GRPCAP_OFFSET);
	dsa->engine_cap.bits = readq(bar0 + IDXD_ENGCAP_OFFSET);

	dsa->table_offsets.bits[0] = readq(bar0 + IDXD_TABLE_OFFSET);
	dsa->table_offsets.bits[1] = readq(bar0 + IDXD_TABLE_OFFSET + 8);

	dsa->wqcfg_table = bar0 + dsa->table_offsets.wqcfg * IDXD_TABLE_MULT;
	dsa->grpcfg_table = bar0 + dsa->table_offsets.grpcfg * IDXD_TABLE_MULT;

	dsa->max_batches = 1U << (dsa->wq_cap.total_wq_size + IDXD_WQCFG_MIN);
	dsa->max_batches = min(dsa->max_batches, ARRAY_SIZE(dsa->batch));

	dsa->max_copies_per_batch = 1UL << dsa->gen_cap.max_batch_shift;
	dsa->max_copies_per_batch = min(dsa->max_copies_per_batch, ARRAY_SIZE(dsa->copy));
}

static void dsa_init(struct vfio_pci_device *device)
{
	struct dsa_state *dsa = to_dsa_state(device);

	VFIO_ASSERT_GE(device->driver.region.size, sizeof(*dsa));

	vfio_pci_config_writew(device, PCI_COMMAND,
			       PCI_COMMAND_MEMORY |
			       PCI_COMMAND_MASTER |
			       PCI_COMMAND_INTX_DISABLE);

	dsa_command(device, IDXD_CMD_RESET_DEVICE);

	dsa_register_cache_init(device);
	dsa_wq_init(device);
	dsa_group_init(device);

	dsa_command(device, IDXD_CMD_ENABLE_DEVICE);
	dsa_command(device, IDXD_CMD_ENABLE_WQ);

	vfio_pci_msix_enable(device, MSIX_VECTOR, 1);

	device->driver.max_memcpy_count =
		dsa->max_batches * dsa->max_copies_per_batch;
	device->driver.max_memcpy_size = 1UL << dsa->gen_cap.max_xfer_shift;
	device->driver.msi = MSIX_VECTOR;
}

static void dsa_remove(struct vfio_pci_device *device)
{
	dsa_command(device, IDXD_CMD_RESET_DEVICE);
	vfio_pci_msix_disable(device);
}

static int dsa_completion_wait(struct vfio_pci_device *device,
			       struct dsa_completion_record *completion)
{
	u8 status;

	for (;;) {
		dsa_check_sw_err(device);

		status = READ_ONCE(completion->status);
		if (status)
			break;

		usleep(1000);
	}

	if (status == DSA_COMP_SUCCESS)
		return 0;

	printf("Error detected during memcpy operation: 0x%x\n", status);
	return -1;
}

static void dsa_copy_desc_init(struct vfio_pci_device *device,
			       struct dsa_hw_desc *desc,
			       iova_t src, iova_t dst, u64 size,
			       bool interrupt)
{
	struct dsa_state *dsa = to_dsa_state(device);
	u16 flags;

	flags = IDXD_OP_FLAG_CRAV | IDXD_OP_FLAG_RCR;

	if (interrupt)
		flags |= IDXD_OP_FLAG_RCI;

	*desc = (struct dsa_hw_desc) {
		.opcode = DSA_OPCODE_MEMMOVE,
		.flags = flags,
		.priv = 1,
		.src_addr = src,
		.dst_addr = dst,
		.xfer_size = size,
		.completion_addr = to_iova(device, &dsa->copy_completion),
		.int_handle = interrupt ? MSIX_VECTOR : 0,
	};
}

static void dsa_batch_desc_init(struct vfio_pci_device *device,
				struct dsa_hw_desc *desc,
				u64 count)
{
	struct dsa_state *dsa = to_dsa_state(device);

	*desc = (struct dsa_hw_desc) {
		.opcode = DSA_OPCODE_BATCH,
		.flags = IDXD_OP_FLAG_CRAV,
		.priv = 1,
		.completion_addr = to_iova(device, &dsa->batch_completion),
		.desc_list_addr = to_iova(device, &dsa->copy[0]),
		.desc_count = count,
	};
}

static void dsa_desc_write(struct vfio_pci_device *device, struct dsa_hw_desc *desc)
{
	/* Write the contents (not address) of the 64-byte descriptor to the device. */
	iosubmit_cmds512(device->bars[2].vaddr, desc, 1);
}

static void dsa_memcpy_one(struct vfio_pci_device *device,
			   iova_t src, iova_t dst, u64 size, bool interrupt)
{
	struct dsa_state *dsa = to_dsa_state(device);

	memset(&dsa->copy_completion, 0, sizeof(dsa->copy_completion));

	dsa_copy_desc_init(device, &dsa->copy[0], src, dst, size, interrupt);
	dsa_desc_write(device, &dsa->copy[0]);
}

static void dsa_memcpy_batch(struct vfio_pci_device *device,
			     iova_t src, iova_t dst, u64 size, u64 count)
{
	struct dsa_state *dsa = to_dsa_state(device);
	int i;

	memset(&dsa->batch_completion, 0, sizeof(dsa->batch_completion));

	for (i = 0; i < ARRAY_SIZE(dsa->copy); i++) {
		struct dsa_hw_desc *copy_desc = &dsa->copy[i];

		dsa_copy_desc_init(device, copy_desc, src, dst, size, false);

		/* Don't request completions for individual copies. */
		copy_desc->flags &= ~IDXD_OP_FLAG_RCR;
	}

	for (i = 0; i < ARRAY_SIZE(dsa->batch) && count; i++) {
		struct dsa_hw_desc *batch_desc = &dsa->batch[i];
		int nr_copies;

		nr_copies = min(count, dsa->max_copies_per_batch);
		count -= nr_copies;

		/*
		 * Batches must have at least 2 copies, so handle the case where
		 * there is exactly 1 copy left by doing one less copy in this
		 * batch and then 2 in the next.
		 */
		if (count == 1) {
			nr_copies--;
			count++;
		}

		dsa_batch_desc_init(device, batch_desc, nr_copies);

		/* Request a completion for the last batch. */
		if (!count)
			batch_desc->flags |= IDXD_OP_FLAG_RCR;

		dsa_desc_write(device, batch_desc);
	}

	VFIO_ASSERT_EQ(count, 0, "Failed to start %lu copies.\n", count);
}

static void dsa_memcpy_start(struct vfio_pci_device *device,
			     iova_t src, iova_t dst, u64 size, u64 count)
{
	struct dsa_state *dsa = to_dsa_state(device);

	/* DSA devices require at least 2 copies per batch. */
	if (count == 1)
		dsa_memcpy_one(device, src, dst, size, false);
	else
		dsa_memcpy_batch(device, src, dst, size, count);

	dsa->memcpy_count = count;
}

static int dsa_memcpy_wait(struct vfio_pci_device *device)
{
	struct dsa_state *dsa = to_dsa_state(device);
	int r;

	if (dsa->memcpy_count == 1)
		r = dsa_completion_wait(device, &dsa->copy_completion);
	else
		r = dsa_completion_wait(device, &dsa->batch_completion);

	dsa->memcpy_count = 0;

	return r;
}

static void dsa_send_msi(struct vfio_pci_device *device)
{
	struct dsa_state *dsa = to_dsa_state(device);

	dsa_memcpy_one(device,
		       to_iova(device, &dsa->send_msi_src),
		       to_iova(device, &dsa->send_msi_dst),
		       sizeof(dsa->send_msi_src), true);

	VFIO_ASSERT_EQ(dsa_completion_wait(device, &dsa->copy_completion), 0);
}

const struct vfio_pci_driver_ops dsa_ops = {
	.name = "dsa",
	.probe = dsa_probe,
	.init = dsa_init,
	.remove = dsa_remove,
	.memcpy_start = dsa_memcpy_start,
	.memcpy_wait = dsa_memcpy_wait,
	.send_msi = dsa_send_msi,
};