ioat.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2#include <stdint.h>
  3#include <unistd.h>
  4
  5#include <linux/errno.h>
  6#include <linux/io.h>
  7#include <linux/pci_ids.h>
  8#include <linux/sizes.h>
  9
 10#include <libvfio.h>
 11
 12#include "hw.h"
 13#include "registers.h"
 14
 15#define IOAT_DMACOUNT_MAX UINT16_MAX
 16
 17struct ioat_state {
 18	/* Single descriptor used to issue DMA memcpy operations */
 19	struct ioat_dma_descriptor desc;
 20
 21	/* Copy buffers used by ioat_send_msi() to generate an interrupt. */
 22	u64 send_msi_src;
 23	u64 send_msi_dst;
 24};
 25
 26static inline struct ioat_state *to_ioat_state(struct vfio_pci_device *device)
 27{
 28	return device->driver.region.vaddr;
 29}
 30
 31static inline void *ioat_channel_registers(struct vfio_pci_device *device)
 32{
 33	return device->bars[0].vaddr + IOAT_CHANNEL_MMIO_SIZE;
 34}
 35
 36static int ioat_probe(struct vfio_pci_device *device)
 37{
 38	u8 version;
 39	int r;
 40
 41	if (!vfio_pci_device_match(device, PCI_VENDOR_ID_INTEL,
 42				   PCI_DEVICE_ID_INTEL_IOAT_SKX))
 43		return -EINVAL;
 44
 45	VFIO_ASSERT_NOT_NULL(device->bars[0].vaddr);
 46
 47	version = readb(device->bars[0].vaddr + IOAT_VER_OFFSET);
 48	switch (version) {
 49	case IOAT_VER_3_2:
 50	case IOAT_VER_3_3:
 51		r = 0;
 52		break;
 53	default:
 54		dev_err(device, "ioat: Unsupported version: 0x%x\n", version);
 55		r = -EINVAL;
 56	}
 57	return r;
 58}
 59
 60static u64 ioat_channel_status(void *bar)
 61{
 62	return readq(bar + IOAT_CHANSTS_OFFSET) & IOAT_CHANSTS_STATUS;
 63}
 64
 65static void ioat_clear_errors(struct vfio_pci_device *device)
 66{
 67	void *registers = ioat_channel_registers(device);
 68	u32 errors;
 69
 70	errors = vfio_pci_config_readl(device, IOAT_PCI_CHANERR_INT_OFFSET);
 71	vfio_pci_config_writel(device, IOAT_PCI_CHANERR_INT_OFFSET, errors);
 72
 73	errors = vfio_pci_config_readl(device, IOAT_PCI_DMAUNCERRSTS_OFFSET);
 74	vfio_pci_config_writel(device, IOAT_PCI_CHANERR_INT_OFFSET, errors);
 75
 76	errors = readl(registers + IOAT_CHANERR_OFFSET);
 77	writel(errors, registers + IOAT_CHANERR_OFFSET);
 78}
 79
 80static void ioat_reset(struct vfio_pci_device *device)
 81{
 82	void *registers = ioat_channel_registers(device);
 83	u32 sleep_ms = 1, attempts = 5000 / sleep_ms;
 84	u8 chancmd;
 85
 86	ioat_clear_errors(device);
 87
 88	writeb(IOAT_CHANCMD_RESET, registers + IOAT2_CHANCMD_OFFSET);
 89
 90	for (;;) {
 91		chancmd = readb(registers + IOAT2_CHANCMD_OFFSET);
 92		if (!(chancmd & IOAT_CHANCMD_RESET))
 93			break;
 94
 95		VFIO_ASSERT_GT(--attempts, 0);
 96		usleep(sleep_ms * 1000);
 97	}
 98
 99	VFIO_ASSERT_EQ(ioat_channel_status(registers), IOAT_CHANSTS_HALTED);
100}
101
102static void ioat_init(struct vfio_pci_device *device)
103{
104	struct ioat_state *ioat = to_ioat_state(device);
105	u8 intrctrl;
106
107	VFIO_ASSERT_GE(device->driver.region.size, sizeof(*ioat));
108
109	vfio_pci_config_writew(device, PCI_COMMAND,
110			       PCI_COMMAND_MEMORY |
111			       PCI_COMMAND_MASTER |
112			       PCI_COMMAND_INTX_DISABLE);
113
114	ioat_reset(device);
115
116	/* Enable the use of MXI-x interrupts for channel interrupts. */
117	intrctrl = IOAT_INTRCTRL_MSIX_VECTOR_CONTROL;
118	writeb(intrctrl, device->bars[0].vaddr + IOAT_INTRCTRL_OFFSET);
119
120	vfio_pci_msix_enable(device, 0, device->msix_info.count);
121
122	device->driver.msi = 0;
123	device->driver.max_memcpy_size =
124		1UL << readb(device->bars[0].vaddr + IOAT_XFERCAP_OFFSET);
125	device->driver.max_memcpy_count = IOAT_DMACOUNT_MAX;
126}
127
128static void ioat_remove(struct vfio_pci_device *device)
129{
130	ioat_reset(device);
131	vfio_pci_msix_disable(device);
132}
133
134static void ioat_handle_error(struct vfio_pci_device *device)
135{
136	void *registers = ioat_channel_registers(device);
137
138	dev_err(device, "Error detected during memcpy operation!\n"
139		 "  CHANERR: 0x%x\n"
140		 "  CHANERR_INT: 0x%x\n"
141		 "  DMAUNCERRSTS: 0x%x\n",
142		 readl(registers + IOAT_CHANERR_OFFSET),
143		 vfio_pci_config_readl(device, IOAT_PCI_CHANERR_INT_OFFSET),
144		 vfio_pci_config_readl(device, IOAT_PCI_DMAUNCERRSTS_OFFSET));
145
146	ioat_reset(device);
147}
148
149static int ioat_memcpy_wait(struct vfio_pci_device *device)
150{
151	void *registers = ioat_channel_registers(device);
152	u64 status;
153	int r = 0;
154
155	/* Wait until all operations complete. */
156	for (;;) {
157		status = ioat_channel_status(registers);
158		if (status == IOAT_CHANSTS_DONE)
159			break;
160
161		if (status == IOAT_CHANSTS_HALTED) {
162			ioat_handle_error(device);
163			return -1;
164		}
165	}
166
167	/* Put the channel into the SUSPENDED state. */
168	writeb(IOAT_CHANCMD_SUSPEND, registers + IOAT2_CHANCMD_OFFSET);
169	for (;;) {
170		status = ioat_channel_status(registers);
171		if (status == IOAT_CHANSTS_SUSPENDED)
172			break;
173	}
174
175	return r;
176}
177
178static void __ioat_memcpy_start(struct vfio_pci_device *device,
179				iova_t src, iova_t dst, u64 size,
180				u16 count, bool interrupt)
181{
182	void *registers = ioat_channel_registers(device);
183	struct ioat_state *ioat = to_ioat_state(device);
184	u64 desc_iova;
185	u16 chanctrl;
186
187	desc_iova = to_iova(device, &ioat->desc);
188	ioat->desc = (struct ioat_dma_descriptor) {
189		.ctl_f.op = IOAT_OP_COPY,
190		.ctl_f.int_en = interrupt,
191		.src_addr = src,
192		.dst_addr = dst,
193		.size = size,
194		.next = desc_iova,
195	};
196
197	/* Tell the device the address of the descriptor. */
198	writeq(desc_iova, registers + IOAT2_CHAINADDR_OFFSET);
199
200	/* (Re)Enable the channel interrupt and abort on any errors */
201	chanctrl = IOAT_CHANCTRL_INT_REARM | IOAT_CHANCTRL_ANY_ERR_ABORT_EN;
202	writew(chanctrl, registers + IOAT_CHANCTRL_OFFSET);
203
204	/* Kick off @count DMA copy operation(s). */
205	writew(count, registers + IOAT_CHAN_DMACOUNT_OFFSET);
206}
207
208static void ioat_memcpy_start(struct vfio_pci_device *device,
209			      iova_t src, iova_t dst, u64 size,
210			      u64 count)
211{
212	__ioat_memcpy_start(device, src, dst, size, count, false);
213}
214
215static void ioat_send_msi(struct vfio_pci_device *device)
216{
217	struct ioat_state *ioat = to_ioat_state(device);
218
219	__ioat_memcpy_start(device,
220			    to_iova(device, &ioat->send_msi_src),
221			    to_iova(device, &ioat->send_msi_dst),
222			    sizeof(ioat->send_msi_src), 1, true);
223
224	VFIO_ASSERT_EQ(ioat_memcpy_wait(device), 0);
225}
226
227const struct vfio_pci_driver_ops ioat_ops = {
228	.name = "ioat",
229	.probe = ioat_probe,
230	.init = ioat_init,
231	.remove = ioat_remove,
232	.memcpy_start = ioat_memcpy_start,
233	.memcpy_wait = ioat_memcpy_wait,
234	.send_msi = ioat_send_msi,
235};