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astlpc.c
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astlpc.c
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/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
#if HAVE_CONFIG_H
#include "config.h"
#endif
#if HAVE_ENDIAN_H
#include <endian.h>
#endif
#include <assert.h>
#include <err.h>
#include <errno.h>
#include <inttypes.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#define pr_fmt(x) "astlpc: " x
#include "container_of.h"
#include "crc32.h"
#include "libmctp.h"
#include "libmctp-alloc.h"
#include "libmctp-log.h"
#include "libmctp-astlpc.h"
#include "range.h"
#ifdef MCTP_HAVE_FILEIO
#include <unistd.h>
#include <fcntl.h>
#include <poll.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <linux/aspeed-lpc-ctrl.h>
/* kernel interface */
static const char *lpc_path = "/dev/aspeed-lpc-ctrl";
#endif
enum mctp_astlpc_cmd {
cmd_initialise = 0x00,
cmd_tx_begin = 0x01,
cmd_rx_complete = 0x02,
cmd_dummy_value = 0xff,
};
enum mctp_astlpc_buffer_state {
/*
* Prior to "Channel Ready" we mark the buffers as "idle" to catch illegal accesses. In this
* state neither side is considered the owner of the buffer.
*
* Upon "Channel Ready", each side transitions the buffers from the initial "idle" state
* to the following target states:
*
* Tx buffer: "acquired"
* Rx buffer: "released"
*/
buffer_state_idle,
/*
* Beyond initialisation by "Channel Ready", buffers are in the "acquired" state once:
*
* 1. We dequeue a control command transferring the buffer to our ownership out of the KCS
* interface, and
* 2. We are yet to complete all of our required accesses to the buffer
*
* * The Tx buffer enters the "acquired" state when we dequeue the "Rx Complete" command
* * The Rx buffer enters the "acquired" state when we dequeue the "Tx Begin" command
*
* It is a failure of implementation if it's possible for both sides to simultaneously
* consider a buffer as "acquired".
*/
buffer_state_acquired,
/*
* Buffers are in the "prepared" state when:
*
* 1. We have completed all of our required accesses (read or write) for the buffer, and
* 2. We have not yet successfully enqueued the control command to hand off ownership
*/
buffer_state_prepared,
/*
* Beyond initialisation by "Channel Ready", buffers are in the "released" state once:
*
* 1. We successfully enqueue the control command transferring ownership to the remote
* side in to the KCS interface
*
* * The Tx buffer enters the "released" state when we enqueue the "Tx Begin" command
* * The Rx buffer enters the "released" state when we enqueue the "Rx Complete" command
*
* It may be the case that both sides simultaneously consider a buffer to be in the
* "released" state. However, if this is true, it must also be true that a buffer ownership
* transfer command has been enqueued in the KCS interface and is yet to be dequeued.
*/
buffer_state_released,
};
struct mctp_astlpc_buffer {
uint32_t offset;
uint32_t size;
enum mctp_astlpc_buffer_state state;
};
struct mctp_astlpc_layout {
struct mctp_astlpc_buffer rx;
struct mctp_astlpc_buffer tx;
};
struct mctp_astlpc_protocol {
uint16_t version;
uint32_t (*packet_size)(uint32_t body);
uint32_t (*body_size)(uint32_t packet);
void (*pktbuf_protect)(struct mctp_pktbuf *pkt);
bool (*pktbuf_validate)(struct mctp_pktbuf *pkt);
};
struct mctp_binding_astlpc {
struct mctp_binding binding;
void *lpc_map;
struct mctp_astlpc_layout layout;
uint8_t mode;
uint32_t requested_mtu;
const struct mctp_astlpc_protocol *proto;
/* direct ops data */
struct mctp_binding_astlpc_ops ops;
void *ops_data;
/* fileio ops data */
int kcs_fd;
uint8_t kcs_status;
};
#define binding_to_astlpc(b) \
container_of(b, struct mctp_binding_astlpc, binding)
#define astlpc_prlog(ctx, lvl, fmt, ...) \
do { \
bool __bmc = ((ctx)->mode == MCTP_BINDING_ASTLPC_MODE_BMC); \
mctp_prlog(lvl, pr_fmt("%s: " fmt), __bmc ? "bmc" : "host", \
##__VA_ARGS__); \
} while (0)
#define astlpc_prerr(ctx, fmt, ...) \
astlpc_prlog(ctx, MCTP_LOG_ERR, fmt, ##__VA_ARGS__)
#define astlpc_prwarn(ctx, fmt, ...) \
astlpc_prlog(ctx, MCTP_LOG_WARNING, fmt, ##__VA_ARGS__)
#define astlpc_prnotice(ctx, fmt, ...) \
astlpc_prlog(ctx, MCTP_LOG_NOTICE, fmt, ##__VA_ARGS__)
#define astlpc_prinfo(ctx, fmt, ...) \
astlpc_prlog(ctx, MCTP_LOG_INFO, fmt, ##__VA_ARGS__)
#define astlpc_prdebug(ctx, fmt, ...) \
astlpc_prlog(ctx, MCTP_LOG_DEBUG, fmt, ##__VA_ARGS__)
/* clang-format off */
#define ASTLPC_MCTP_MAGIC 0x4d435450
#define ASTLPC_VER_BAD 0
#define ASTLPC_VER_MIN 1
/* Support testing of new binding protocols */
#ifndef ASTLPC_VER_CUR
#define ASTLPC_VER_CUR 3
#endif
/* clang-format on */
#ifndef ARRAY_SIZE
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
#endif
static uint32_t astlpc_packet_size_v1(uint32_t body)
{
assert((body + 4) > body);
return body + 4;
}
static uint32_t astlpc_body_size_v1(uint32_t packet)
{
assert((packet - 4) < packet);
return packet - 4;
}
void astlpc_pktbuf_protect_v1(struct mctp_pktbuf *pkt)
{
(void)pkt;
}
bool astlpc_pktbuf_validate_v1(struct mctp_pktbuf *pkt)
{
(void)pkt;
return true;
}
static uint32_t astlpc_packet_size_v3(uint32_t body)
{
assert((body + 4 + 4) > body);
return body + 4 + 4;
}
static uint32_t astlpc_body_size_v3(uint32_t packet)
{
assert((packet - 4 - 4) < packet);
return packet - 4 - 4;
}
void astlpc_pktbuf_protect_v3(struct mctp_pktbuf *pkt)
{
uint32_t code;
code = htobe32(crc32(mctp_pktbuf_hdr(pkt), mctp_pktbuf_size(pkt)));
mctp_prdebug("%s: 0x%" PRIx32, __func__, code);
mctp_pktbuf_push(pkt, &code, 4);
}
bool astlpc_pktbuf_validate_v3(struct mctp_pktbuf *pkt)
{
uint32_t code;
void *check;
code = be32toh(crc32(mctp_pktbuf_hdr(pkt), mctp_pktbuf_size(pkt) - 4));
mctp_prdebug("%s: 0x%" PRIx32, __func__, code);
check = mctp_pktbuf_pop(pkt, 4);
return check && !memcmp(&code, check, 4);
}
static const struct mctp_astlpc_protocol astlpc_protocol_version[] = {
[0] = {
.version = 0,
.packet_size = NULL,
.body_size = NULL,
.pktbuf_protect = NULL,
.pktbuf_validate = NULL,
},
[1] = {
.version = 1,
.packet_size = astlpc_packet_size_v1,
.body_size = astlpc_body_size_v1,
.pktbuf_protect = astlpc_pktbuf_protect_v1,
.pktbuf_validate = astlpc_pktbuf_validate_v1,
},
[2] = {
.version = 2,
.packet_size = astlpc_packet_size_v1,
.body_size = astlpc_body_size_v1,
.pktbuf_protect = astlpc_pktbuf_protect_v1,
.pktbuf_validate = astlpc_pktbuf_validate_v1,
},
[3] = {
.version = 3,
.packet_size = astlpc_packet_size_v3,
.body_size = astlpc_body_size_v3,
.pktbuf_protect = astlpc_pktbuf_protect_v3,
.pktbuf_validate = astlpc_pktbuf_validate_v3,
},
};
struct mctp_lpcmap_hdr {
uint32_t magic;
uint16_t bmc_ver_min;
uint16_t bmc_ver_cur;
uint16_t host_ver_min;
uint16_t host_ver_cur;
uint16_t negotiated_ver;
uint16_t pad0;
struct {
uint32_t rx_offset;
uint32_t rx_size;
uint32_t tx_offset;
uint32_t tx_size;
} layout;
} __attribute__((packed));
static const uint32_t control_size = 0x100;
#define LPC_WIN_SIZE (1 * 1024 * 1024)
#define KCS_STATUS_BMC_READY 0x80
#define KCS_STATUS_CHANNEL_ACTIVE 0x40
#define KCS_STATUS_IBF 0x02
#define KCS_STATUS_OBF 0x01
static inline int mctp_astlpc_kcs_write(struct mctp_binding_astlpc *astlpc,
enum mctp_binding_astlpc_kcs_reg reg,
uint8_t val)
{
return astlpc->ops.kcs_write(astlpc->ops_data, reg, val);
}
static inline int mctp_astlpc_kcs_read(struct mctp_binding_astlpc *astlpc,
enum mctp_binding_astlpc_kcs_reg reg,
uint8_t *val)
{
return astlpc->ops.kcs_read(astlpc->ops_data, reg, val);
}
static inline int mctp_astlpc_lpc_write(struct mctp_binding_astlpc *astlpc,
const void *buf, long offset,
size_t len)
{
astlpc_prdebug(astlpc, "%s: %zu bytes to 0x%lx", __func__, len, offset);
assert(offset >= 0);
/* Indirect access */
if (astlpc->ops.lpc_write) {
void *data = astlpc->ops_data;
return astlpc->ops.lpc_write(data, buf, offset, len);
}
/* Direct mapping */
assert(astlpc->lpc_map);
memcpy(&((char *)astlpc->lpc_map)[offset], buf, len);
return 0;
}
static inline int mctp_astlpc_lpc_read(struct mctp_binding_astlpc *astlpc,
void *buf, long offset, size_t len)
{
astlpc_prdebug(astlpc, "%s: %zu bytes from 0x%lx", __func__, len,
offset);
assert(offset >= 0);
/* Indirect access */
if (astlpc->ops.lpc_read) {
void *data = astlpc->ops_data;
return astlpc->ops.lpc_read(data, buf, offset, len);
}
/* Direct mapping */
assert(astlpc->lpc_map);
memcpy(buf, &((char *)astlpc->lpc_map)[offset], len);
return 0;
}
static void
mctp_astlpc_kcs_print_status_write(struct mctp_binding_astlpc *astlpc,
uint8_t status)
{
astlpc_prnotice(
astlpc, "Binding state is 0x%hhx: BMC %s, Channel %s, OBF %s",
status, status & KCS_STATUS_BMC_READY ? "active" : "inactive",
status & KCS_STATUS_CHANNEL_ACTIVE ? "active" : "inactive",
status & KCS_STATUS_OBF ? "preserved" : "cleared");
}
static int mctp_astlpc_kcs_set_status(struct mctp_binding_astlpc *astlpc,
uint8_t status)
{
uint8_t data;
int rc;
/* Since we're setting the status register, we want the other endpoint
* to be interrupted. However, some hardware may only raise a host-side
* interrupt on an ODR event.
* So, write a dummy value of 0xff to ODR, which will ensure that an
* interrupt is triggered, and can be ignored by the host.
*/
data = cmd_dummy_value;
rc = mctp_astlpc_kcs_write(astlpc, MCTP_ASTLPC_KCS_REG_STATUS, status);
if (rc) {
astlpc_prwarn(astlpc, "KCS status write failed");
return -1;
}
mctp_astlpc_kcs_print_status_write(astlpc, status);
rc = mctp_astlpc_kcs_write(astlpc, MCTP_ASTLPC_KCS_REG_DATA, data);
if (rc) {
astlpc_prwarn(astlpc, "KCS dummy data write failed");
return -1;
}
return 0;
}
static int mctp_astlpc_layout_read(struct mctp_binding_astlpc *astlpc,
struct mctp_astlpc_layout *layout)
{
struct mctp_lpcmap_hdr hdr;
int rc;
rc = mctp_astlpc_lpc_read(astlpc, &hdr, 0, sizeof(hdr));
if (rc < 0)
return rc;
/* Flip the buffers as the names are defined in terms of the host */
if (astlpc->mode == MCTP_BINDING_ASTLPC_MODE_BMC) {
layout->rx.offset = be32toh(hdr.layout.tx_offset);
layout->rx.size = be32toh(hdr.layout.tx_size);
layout->tx.offset = be32toh(hdr.layout.rx_offset);
layout->tx.size = be32toh(hdr.layout.rx_size);
} else {
assert(astlpc->mode == MCTP_BINDING_ASTLPC_MODE_HOST);
layout->rx.offset = be32toh(hdr.layout.rx_offset);
layout->rx.size = be32toh(hdr.layout.rx_size);
layout->tx.offset = be32toh(hdr.layout.tx_offset);
layout->tx.size = be32toh(hdr.layout.tx_size);
}
return 0;
}
static int mctp_astlpc_layout_write(struct mctp_binding_astlpc *astlpc,
struct mctp_astlpc_layout *layout)
{
uint32_t rx_size_be;
if (astlpc->mode == MCTP_BINDING_ASTLPC_MODE_BMC) {
struct mctp_lpcmap_hdr hdr;
/*
* Flip the buffers as the names are defined in terms of the
* host
*/
hdr.layout.rx_offset = htobe32(layout->tx.offset);
hdr.layout.rx_size = htobe32(layout->tx.size);
hdr.layout.tx_offset = htobe32(layout->rx.offset);
hdr.layout.tx_size = htobe32(layout->rx.size);
return mctp_astlpc_lpc_write(astlpc, &hdr.layout,
offsetof(struct mctp_lpcmap_hdr,
layout),
sizeof(hdr.layout));
}
assert(astlpc->mode == MCTP_BINDING_ASTLPC_MODE_HOST);
/*
* As of v2 we only need to write rx_size - the offsets are controlled
* by the BMC, as is the BMC's rx_size (host tx_size).
*/
rx_size_be = htobe32(layout->rx.size);
return mctp_astlpc_lpc_write(astlpc, &rx_size_be,
offsetof(struct mctp_lpcmap_hdr,
layout.rx_size),
sizeof(rx_size_be));
}
static bool
mctp_astlpc_buffer_validate(const struct mctp_binding_astlpc *astlpc,
const struct mctp_astlpc_buffer *buf,
const char *name)
{
/* Check for overflow */
if (buf->offset + buf->size < buf->offset) {
mctp_prerr(
"%s packet buffer parameters overflow: offset: 0x%" PRIx32
", size: %" PRIu32,
name, buf->offset, buf->size);
return false;
}
/* Check that the buffers are contained within the allocated space */
if (buf->offset + buf->size > LPC_WIN_SIZE) {
mctp_prerr(
"%s packet buffer parameters exceed %uM window size: offset: 0x%" PRIx32
", size: %" PRIu32,
name, (LPC_WIN_SIZE / (1024 * 1024)), buf->offset,
buf->size);
return false;
}
/* Check that the baseline transmission unit is supported */
if (buf->size <
astlpc->proto->packet_size(MCTP_PACKET_SIZE(MCTP_BTU))) {
mctp_prerr(
"%s packet buffer too small: Require %" PRIu32
" bytes to support the %u byte baseline transmission unit, found %" PRIu32,
name,
astlpc->proto->packet_size(MCTP_PACKET_SIZE(MCTP_BTU)),
MCTP_BTU, buf->size);
return false;
}
/* Check for overlap with the control space */
if (buf->offset < control_size) {
mctp_prerr(
"%s packet buffer overlaps control region {0x%" PRIx32
", %" PRIu32 "}: Rx {0x%" PRIx32 ", %" PRIu32 "}",
name, 0U, control_size, buf->offset, buf->size);
return false;
}
return true;
}
static bool
mctp_astlpc_layout_validate(const struct mctp_binding_astlpc *astlpc,
const struct mctp_astlpc_layout *layout)
{
const struct mctp_astlpc_buffer *rx = &layout->rx;
const struct mctp_astlpc_buffer *tx = &layout->tx;
bool rx_valid, tx_valid;
rx_valid = mctp_astlpc_buffer_validate(astlpc, rx, "Rx");
tx_valid = mctp_astlpc_buffer_validate(astlpc, tx, "Tx");
if (!(rx_valid && tx_valid))
return false;
/* Check that the buffers are disjoint */
if ((rx->offset <= tx->offset && rx->offset + rx->size > tx->offset) ||
(tx->offset <= rx->offset && tx->offset + tx->size > rx->offset)) {
mctp_prerr("Rx and Tx packet buffers overlap: Rx {0x%" PRIx32
", %" PRIu32 "}, Tx {0x%" PRIx32 ", %" PRIu32 "}",
rx->offset, rx->size, tx->offset, tx->size);
return false;
}
return true;
}
static int mctp_astlpc_init_bmc(struct mctp_binding_astlpc *astlpc)
{
struct mctp_lpcmap_hdr hdr = { 0 };
uint8_t status;
uint32_t sz;
/*
* The largest buffer size is half of the allocated MCTP space
* excluding the control space.
*/
sz = ((LPC_WIN_SIZE - control_size) / 2);
/*
* Trim the MTU to a multiple of 16 to meet the requirements of 12.17
* Query Hop in DSP0236 v1.3.0.
*/
sz = MCTP_BODY_SIZE(astlpc->proto->body_size(sz));
sz &= ~0xfUL;
sz = astlpc->proto->packet_size(MCTP_PACKET_SIZE(sz));
if (astlpc->requested_mtu) {
uint32_t rpkt, rmtu;
rmtu = astlpc->requested_mtu;
rpkt = astlpc->proto->packet_size(MCTP_PACKET_SIZE(rmtu));
sz = MIN(sz, rpkt);
}
/* Flip the buffers as the names are defined in terms of the host */
astlpc->layout.tx.offset = control_size;
astlpc->layout.tx.size = sz;
astlpc->layout.rx.offset =
astlpc->layout.tx.offset + astlpc->layout.tx.size;
astlpc->layout.rx.size = sz;
if (!mctp_astlpc_layout_validate(astlpc, &astlpc->layout)) {
astlpc_prerr(astlpc, "Cannot support an MTU of %" PRIu32, sz);
return -EINVAL;
}
hdr = (struct mctp_lpcmap_hdr){
.magic = htobe32(ASTLPC_MCTP_MAGIC),
.bmc_ver_min = htobe16(ASTLPC_VER_MIN),
.bmc_ver_cur = htobe16(ASTLPC_VER_CUR),
/* Flip the buffers back as we're now describing the host's
* configuration to the host */
.layout.rx_offset = htobe32(astlpc->layout.tx.offset),
.layout.rx_size = htobe32(astlpc->layout.tx.size),
.layout.tx_offset = htobe32(astlpc->layout.rx.offset),
.layout.tx_size = htobe32(astlpc->layout.rx.size),
};
mctp_astlpc_lpc_write(astlpc, &hdr, 0, sizeof(hdr));
/*
* Set status indicating that the BMC is now active. Be explicit about
* clearing OBF; we're reinitialising the binding and so any previous
* buffer state is irrelevant.
*/
status = KCS_STATUS_BMC_READY & ~KCS_STATUS_OBF;
return mctp_astlpc_kcs_set_status(astlpc, status);
}
static int mctp_binding_astlpc_start_bmc(struct mctp_binding *b)
{
struct mctp_binding_astlpc *astlpc =
container_of(b, struct mctp_binding_astlpc, binding);
astlpc->proto = &astlpc_protocol_version[ASTLPC_VER_CUR];
return mctp_astlpc_init_bmc(astlpc);
}
static bool mctp_astlpc_validate_version(uint16_t bmc_ver_min,
uint16_t bmc_ver_cur,
uint16_t host_ver_min,
uint16_t host_ver_cur)
{
if (!(bmc_ver_min && bmc_ver_cur && host_ver_min && host_ver_cur)) {
mctp_prerr("Invalid version present in [%" PRIu16 ", %" PRIu16
"], [%" PRIu16 ", %" PRIu16 "]",
bmc_ver_min, bmc_ver_cur, host_ver_min,
host_ver_cur);
return false;
} else if (bmc_ver_min > bmc_ver_cur) {
mctp_prerr("Invalid bmc version range [%" PRIu16 ", %" PRIu16
"]",
bmc_ver_min, bmc_ver_cur);
return false;
} else if (host_ver_min > host_ver_cur) {
mctp_prerr("Invalid host version range [%" PRIu16 ", %" PRIu16
"]",
host_ver_min, host_ver_cur);
return false;
} else if ((host_ver_cur < bmc_ver_min) ||
(host_ver_min > bmc_ver_cur)) {
mctp_prerr(
"Unable to satisfy version negotiation with ranges [%" PRIu16
", %" PRIu16 "] and [%" PRIu16 ", %" PRIu16 "]",
bmc_ver_min, bmc_ver_cur, host_ver_min, host_ver_cur);
return false;
}
return true;
}
static int mctp_astlpc_negotiate_layout_host(struct mctp_binding_astlpc *astlpc)
{
struct mctp_astlpc_layout layout;
uint32_t rmtu;
uint32_t sz;
int rc;
rc = mctp_astlpc_layout_read(astlpc, &layout);
if (rc < 0)
return rc;
if (!mctp_astlpc_layout_validate(astlpc, &layout)) {
astlpc_prerr(
astlpc,
"BMC provided invalid buffer layout: Rx {0x%" PRIx32
", %" PRIu32 "}, Tx {0x%" PRIx32 ", %" PRIu32 "}",
layout.rx.offset, layout.rx.size, layout.tx.offset,
layout.tx.size);
return -EINVAL;
}
astlpc_prinfo(astlpc, "Desire an MTU of %" PRIu32 " bytes",
astlpc->requested_mtu);
rmtu = astlpc->requested_mtu;
sz = astlpc->proto->packet_size(MCTP_PACKET_SIZE(rmtu));
layout.rx.size = sz;
if (!mctp_astlpc_layout_validate(astlpc, &layout)) {
astlpc_prerr(
astlpc,
"Generated invalid buffer layout with size %" PRIu32
": Rx {0x%" PRIx32 ", %" PRIu32 "}, Tx {0x%" PRIx32
", %" PRIu32 "}",
sz, layout.rx.offset, layout.rx.size, layout.tx.offset,
layout.tx.size);
return -EINVAL;
}
astlpc_prinfo(astlpc, "Requesting MTU of %" PRIu32 " bytes",
astlpc->requested_mtu);
return mctp_astlpc_layout_write(astlpc, &layout);
}
static uint16_t mctp_astlpc_negotiate_version(uint16_t bmc_ver_min,
uint16_t bmc_ver_cur,
uint16_t host_ver_min,
uint16_t host_ver_cur)
{
if (!mctp_astlpc_validate_version(bmc_ver_min, bmc_ver_cur,
host_ver_min, host_ver_cur))
return ASTLPC_VER_BAD;
if (bmc_ver_cur < host_ver_cur)
return bmc_ver_cur;
return host_ver_cur;
}
static int mctp_astlpc_init_host(struct mctp_binding_astlpc *astlpc)
{
const uint16_t ver_min_be = htobe16(ASTLPC_VER_MIN);
const uint16_t ver_cur_be = htobe16(ASTLPC_VER_CUR);
uint16_t bmc_ver_min, bmc_ver_cur, negotiated;
struct mctp_lpcmap_hdr hdr;
uint8_t status;
int rc;
rc = mctp_astlpc_kcs_read(astlpc, MCTP_ASTLPC_KCS_REG_STATUS, &status);
if (rc) {
mctp_prwarn("KCS status read failed");
return rc;
}
astlpc->kcs_status = status;
if (!(status & KCS_STATUS_BMC_READY))
return -EHOSTDOWN;
mctp_astlpc_lpc_read(astlpc, &hdr, 0, sizeof(hdr));
bmc_ver_min = be16toh(hdr.bmc_ver_min);
bmc_ver_cur = be16toh(hdr.bmc_ver_cur);
/* Calculate the expected value of negotiated_ver */
negotiated = mctp_astlpc_negotiate_version(
bmc_ver_min, bmc_ver_cur, ASTLPC_VER_MIN, ASTLPC_VER_CUR);
if (!negotiated) {
astlpc_prerr(astlpc, "Cannot negotiate with invalid versions");
return -EINVAL;
}
/* Assign protocol ops so we can calculate the packet buffer sizes */
assert(negotiated < ARRAY_SIZE(astlpc_protocol_version));
astlpc->proto = &astlpc_protocol_version[negotiated];
/* Negotiate packet buffers in v2 style if the BMC supports it */
if (negotiated >= 2) {
rc = mctp_astlpc_negotiate_layout_host(astlpc);
if (rc < 0)
return rc;
}
/* Advertise the host's supported protocol versions */
mctp_astlpc_lpc_write(astlpc, &ver_min_be,
offsetof(struct mctp_lpcmap_hdr, host_ver_min),
sizeof(ver_min_be));
mctp_astlpc_lpc_write(astlpc, &ver_cur_be,
offsetof(struct mctp_lpcmap_hdr, host_ver_cur),
sizeof(ver_cur_be));
/* Send channel init command */
rc = mctp_astlpc_kcs_write(astlpc, MCTP_ASTLPC_KCS_REG_DATA, 0x0);
if (rc) {
astlpc_prwarn(astlpc, "KCS write failed");
}
/*
* Configure the host so `astlpc->proto->version == 0` holds until we
* receive a subsequent status update from the BMC. Until then,
* `astlpc->proto->version == 0` indicates that we're yet to complete
* the channel initialisation handshake.
*
* When the BMC provides a status update with KCS_STATUS_CHANNEL_ACTIVE
* set we will assign the appropriate protocol ops struct in accordance
* with `negotiated_ver`.
*/
astlpc->proto = &astlpc_protocol_version[ASTLPC_VER_BAD];
return rc;
}
static int mctp_binding_astlpc_start_host(struct mctp_binding *b)
{
struct mctp_binding_astlpc *astlpc =
container_of(b, struct mctp_binding_astlpc, binding);
return mctp_astlpc_init_host(astlpc);
}
static bool __mctp_astlpc_kcs_ready(struct mctp_binding_astlpc *astlpc,
uint8_t status, bool is_write)
{
bool is_bmc;
bool ready_state;
uint8_t flag;
is_bmc = (astlpc->mode == MCTP_BINDING_ASTLPC_MODE_BMC);
flag = (is_bmc ^ is_write) ? KCS_STATUS_IBF : KCS_STATUS_OBF;
ready_state = is_write ? 0 : 1;
return !!(status & flag) == ready_state;
}
static inline bool
mctp_astlpc_kcs_read_ready(struct mctp_binding_astlpc *astlpc, uint8_t status)
{
return __mctp_astlpc_kcs_ready(astlpc, status, false);
}
static inline bool
mctp_astlpc_kcs_write_ready(struct mctp_binding_astlpc *astlpc, uint8_t status)
{
return __mctp_astlpc_kcs_ready(astlpc, status, true);
}
static int mctp_astlpc_kcs_send(struct mctp_binding_astlpc *astlpc,
enum mctp_astlpc_cmd data)
{
uint8_t status;
int rc;
rc = mctp_astlpc_kcs_read(astlpc, MCTP_ASTLPC_KCS_REG_STATUS, &status);
if (rc) {
astlpc_prwarn(astlpc, "KCS status read failed");
return -EIO;
}
if (!mctp_astlpc_kcs_write_ready(astlpc, status))
return -EBUSY;
rc = mctp_astlpc_kcs_write(astlpc, MCTP_ASTLPC_KCS_REG_DATA, data);
if (rc) {
astlpc_prwarn(astlpc, "KCS data write failed");
return -EIO;
}
return 0;
}
static int mctp_binding_astlpc_tx(struct mctp_binding *b,
struct mctp_pktbuf *pkt)
{
struct mctp_binding_astlpc *astlpc = binding_to_astlpc(b);
uint32_t len, len_be;
struct mctp_hdr *hdr;
int rc;
hdr = mctp_pktbuf_hdr(pkt);
len = mctp_pktbuf_size(pkt);
astlpc_prdebug(astlpc,
"%s: Transmitting %" PRIu32
"-byte packet (%hhu, %hhu, 0x%hhx)",
__func__, len, hdr->src, hdr->dest, hdr->flags_seq_tag);
if (len > astlpc->proto->body_size(astlpc->layout.tx.size)) {
astlpc_prwarn(astlpc, "invalid TX len %" PRIu32 ": %" PRIu32,
len,
astlpc->proto->body_size(astlpc->layout.tx.size));
return -EMSGSIZE;
}
mctp_binding_set_tx_enabled(b, false);
len_be = htobe32(len);
mctp_astlpc_lpc_write(astlpc, &len_be, astlpc->layout.tx.offset,
sizeof(len_be));
astlpc->proto->pktbuf_protect(pkt);
len = mctp_pktbuf_size(pkt);
mctp_astlpc_lpc_write(astlpc, hdr, astlpc->layout.tx.offset + 4, len);
astlpc->layout.tx.state = buffer_state_prepared;
rc = mctp_astlpc_kcs_send(astlpc, cmd_tx_begin);
if (!rc)
astlpc->layout.tx.state = buffer_state_released;
return rc == -EBUSY ? 0 : rc;
}
/* Update binding pkt_size and reallocate tx_storage */
static int mctp_astlpc_set_pkt_size(struct mctp_binding_astlpc *astlpc,
size_t pkt_size)
{
size_t body = MCTP_BODY_SIZE(pkt_size);
body += astlpc->binding.pkt_header + astlpc->binding.pkt_trailer;
size_t pktbuf_size = MCTP_PKTBUF_SIZE(body);
/* Reallocate TX storage */
if (astlpc->binding.tx_storage) {
__mctp_free(astlpc->binding.tx_storage);
}
astlpc->binding.tx_storage = __mctp_alloc(pktbuf_size);
if (!astlpc->binding.tx_storage) {
return -ENOMEM;
}
astlpc->binding.pkt_size = pkt_size;
return 0;
}
static uint32_t mctp_astlpc_calculate_mtu(struct mctp_binding_astlpc *astlpc,
struct mctp_astlpc_layout *layout)
{
uint32_t low, high, limit, rpkt;
/* Derive the largest MTU the BMC _can_ support */
low = MIN(astlpc->layout.rx.offset, astlpc->layout.tx.offset);
high = MAX(astlpc->layout.rx.offset, astlpc->layout.tx.offset);
limit = high - low;
/* Determine the largest MTU the BMC _wants_ to support */
if (astlpc->requested_mtu) {
uint32_t rmtu = astlpc->requested_mtu;
rpkt = astlpc->proto->packet_size(MCTP_PACKET_SIZE(rmtu));
limit = MIN(limit, rpkt);
}
/* Determine the accepted MTU, applied both directions by convention */
rpkt = MIN(limit, layout->tx.size);
return MCTP_BODY_SIZE(astlpc->proto->body_size(rpkt));
}
static int mctp_astlpc_negotiate_layout_bmc(struct mctp_binding_astlpc *astlpc)
{
struct mctp_astlpc_layout proposed, pending;
uint32_t sz, mtu;
int rc;
/* Do we have a valid protocol version? */
if (!astlpc->proto->version)
return -EINVAL;
/* Extract the host's proposed layout */
rc = mctp_astlpc_layout_read(astlpc, &proposed);
if (rc < 0)
return rc;
/* Do we have a reasonable layout? */
if (!mctp_astlpc_layout_validate(astlpc, &proposed))
return -EINVAL;
/* Negotiate the MTU */
mtu = mctp_astlpc_calculate_mtu(astlpc, &proposed);
sz = astlpc->proto->packet_size(MCTP_PACKET_SIZE(mtu));
/*
* Use symmetric MTUs by convention and to pass constraints in rx/tx
* functions
*/
pending = astlpc->layout;
pending.tx.size = sz;
pending.rx.size = sz;
if (mctp_astlpc_layout_validate(astlpc, &pending)) {
/* We found a sensible Rx MTU, so honour it */
astlpc->layout = pending;
/* Enforce the negotiated MTU */
rc = mctp_astlpc_layout_write(astlpc, &astlpc->layout);
if (rc < 0)
return rc;
astlpc_prinfo(astlpc, "Negotiated an MTU of %" PRIu32 " bytes",
mtu);
} else {
astlpc_prwarn(astlpc, "MTU negotiation failed");
return -EINVAL;
}
if (astlpc->proto->version >= 2) {
rc = mctp_astlpc_set_pkt_size(astlpc, MCTP_PACKET_SIZE(mtu));
if (rc) {
astlpc_prwarn(astlpc, "Allocation error");
return rc;
}
}
return 0;
}
static void mctp_astlpc_init_channel(struct mctp_binding_astlpc *astlpc)
{
uint16_t negotiated, negotiated_be;
struct mctp_lpcmap_hdr hdr;
uint8_t status;
int rc;
mctp_astlpc_lpc_read(astlpc, &hdr, 0, sizeof(hdr));
/* Version negotiation */
negotiated = mctp_astlpc_negotiate_version(ASTLPC_VER_MIN,
ASTLPC_VER_CUR,
be16toh(hdr.host_ver_min),
be16toh(hdr.host_ver_cur));
/* MTU negotiation requires knowing which protocol we'll use */
assert(negotiated < ARRAY_SIZE(astlpc_protocol_version));
astlpc->proto = &astlpc_protocol_version[negotiated];
/* Host Rx MTU negotiation: Failure terminates channel init */
rc = mctp_astlpc_negotiate_layout_bmc(astlpc);
if (rc < 0)
negotiated = ASTLPC_VER_BAD;
/* Populate the negotiated version */
negotiated_be = htobe16(negotiated);
mctp_astlpc_lpc_write(astlpc, &negotiated_be,