[PATCH v2 2/4] ipmi: bt-i2c: added IPMI Block Transfer over I2C host side
Brendan Higgins
brendanhiggins at google.com
Sat Aug 5 11:18:53 AEST 2017
The IPMI definition of the Block Transfer protocol defines the hardware
registers and behavior in addition to the message format and messaging
semantics. This implements a new protocol that uses IPMI Block Transfer
messages and semantics on top of a standard I2C interface.
Signed-off-by: Brendan Higgins <brendanhiggins at google.com>
---
Changes for v2:
- None
---
drivers/char/ipmi/Kconfig | 4 +
drivers/char/ipmi/Makefile | 1 +
drivers/char/ipmi/ipmi_bt_i2c.c | 452 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 457 insertions(+)
create mode 100644 drivers/char/ipmi/ipmi_bt_i2c.c
diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index f6fa056a52fc..a8734a369cb0 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -79,6 +79,10 @@ config IPMI_POWEROFF
This enables a function to power off the system with IPMI if
the IPMI management controller is capable of this.
+config IPMI_BT_I2C
+ select I2C
+ tristate 'BT IPMI bmc driver over I2c'
+
endif # IPMI_HANDLER
config ASPEED_BT_IPMI_BMC
diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
index eefb0b301e83..323de0b0b8b5 100644
--- a/drivers/char/ipmi/Makefile
+++ b/drivers/char/ipmi/Makefile
@@ -12,4 +12,5 @@ obj-$(CONFIG_IPMI_SSIF) += ipmi_ssif.o
obj-$(CONFIG_IPMI_POWERNV) += ipmi_powernv.o
obj-$(CONFIG_IPMI_WATCHDOG) += ipmi_watchdog.o
obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o
+obj-$(CONFIG_IPMI_BT_I2C) += ipmi_bt_i2c.o
obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
diff --git a/drivers/char/ipmi/ipmi_bt_i2c.c b/drivers/char/ipmi/ipmi_bt_i2c.c
new file mode 100644
index 000000000000..94b5c11d23cd
--- /dev/null
+++ b/drivers/char/ipmi/ipmi_bt_i2c.c
@@ -0,0 +1,452 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) "ipmi-bt-i2c: " fmt
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/errno.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/ipmi_smi.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
+#include <linux/types.h>
+
+#define IPMI_BT_I2C_TIMEOUT (msecs_to_jiffies(1000))
+
+/* If we don't have netfn_lun, seq, and cmd, we might as well have nothing. */
+#define IPMI_BT_I2C_LEN_MIN 3
+/* We need at least netfn_lun, seq, cmd, and completion. */
+#define IPMI_BT_I2C_RESPONSE_LEN_MIN 4
+#define IPMI_BT_I2C_MSG_MAX_PAYLOAD_SIZE 252
+
+struct ipmi_bt_i2c_msg {
+ u8 len;
+ u8 netfn_lun;
+ u8 seq;
+ u8 cmd;
+ u8 payload[IPMI_BT_I2C_MSG_MAX_PAYLOAD_SIZE];
+} __packed;
+
+#define IPMI_BT_I2C_MAX_SMI_SIZE 254 /* Need extra byte for seq. */
+#define IPMI_BT_I2C_SMI_MSG_HEADER_SIZE 2
+
+struct ipmi_bt_i2c_smi_msg {
+ u8 netfn_lun;
+ u8 cmd;
+ u8 payload[IPMI_MAX_MSG_LENGTH - 2];
+} __packed;
+
+static inline u32 bt_msg_len(struct ipmi_bt_i2c_msg *bt_request)
+{
+ return bt_request->len + 1;
+}
+
+#define IPMI_BT_I2C_SEQ_MAX 256
+
+struct ipmi_bt_i2c_seq_entry {
+ struct ipmi_smi_msg *msg;
+ unsigned long send_time;
+};
+
+struct ipmi_bt_i2c_master {
+ struct ipmi_device_id ipmi_id;
+ struct i2c_client *client;
+ ipmi_smi_t intf;
+ spinlock_t lock;
+ struct ipmi_bt_i2c_seq_entry seq_msg_map[IPMI_BT_I2C_SEQ_MAX];
+ struct work_struct ipmi_bt_i2c_recv_work;
+ struct work_struct ipmi_bt_i2c_send_work;
+ struct ipmi_smi_msg *msg_to_send;
+};
+
+static const unsigned long write_timeout = 25;
+
+static int ipmi_bt_i2c_send_request(struct ipmi_bt_i2c_master *master,
+ struct ipmi_bt_i2c_msg *request)
+{
+ struct i2c_client *client = master->client;
+ unsigned long timeout, read_time;
+ u8 *buf = (u8 *) request;
+ int ret;
+
+ timeout = jiffies + msecs_to_jiffies(write_timeout);
+ do {
+ read_time = jiffies;
+ ret = i2c_master_send(client, buf, bt_msg_len(request));
+ if (ret >= 0)
+ return 0;
+ usleep_range(1000, 1500);
+ } while (time_before(read_time, timeout));
+ return ret;
+}
+
+static int ipmi_bt_i2c_receive_response(struct ipmi_bt_i2c_master *master,
+ struct ipmi_bt_i2c_msg *response)
+{
+ struct i2c_client *client = master->client;
+ unsigned long timeout, read_time;
+ u8 *buf = (u8 *) response;
+ u8 len = 0;
+ int ret;
+
+ /*
+ * Slave may not NACK when not ready, so we peek at the first byte to
+ * see if it is a valid length.
+ */
+ ret = i2c_master_recv(client, &len, 1);
+ while (ret != 1 || len == 0) {
+ if (ret < 0)
+ return ret;
+
+ usleep_range(1000, 1500);
+
+ /* Signal received: quit syscall. */
+ if (signal_pending(current))
+ return -ERESTARTSYS;
+
+ ret = i2c_master_recv(client, &len, 1);
+ }
+
+ timeout = jiffies + msecs_to_jiffies(write_timeout);
+ do {
+ read_time = jiffies;
+ ret = i2c_master_recv(client, buf, len + 1);
+ if (ret >= 0)
+ return 0;
+ usleep_range(1000, 1500);
+ } while (time_before(read_time, timeout));
+ return ret;
+}
+
+static int ipmi_bt_i2c_start_processing(void *data, ipmi_smi_t intf)
+{
+ struct ipmi_bt_i2c_master *master = data;
+
+ master->intf = intf;
+
+ return 0;
+}
+
+static void __ipmi_bt_i2c_error_reply(struct ipmi_bt_i2c_master *master,
+ struct ipmi_smi_msg *msg,
+ u8 completion_code)
+{
+ struct ipmi_bt_i2c_smi_msg *response;
+ struct ipmi_bt_i2c_smi_msg *request;
+
+ response = (struct ipmi_bt_i2c_smi_msg *) msg->rsp;
+ request = (struct ipmi_bt_i2c_smi_msg *) msg->data;
+
+ response->netfn_lun = request->netfn_lun | 0x4;
+ response->cmd = request->cmd;
+ response->payload[0] = completion_code;
+ msg->rsp_size = 3;
+ ipmi_smi_msg_received(master->intf, msg);
+}
+
+static void ipmi_bt_i2c_error_reply(struct ipmi_bt_i2c_master *master,
+ struct ipmi_smi_msg *msg,
+ u8 completion_code)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&master->lock, flags);
+ __ipmi_bt_i2c_error_reply(master, msg, completion_code);
+ spin_unlock_irqrestore(&master->lock, flags);
+}
+
+/*
+ * ipmi_bt_i2c_smi_msg contains a payload and 2 header fields, each 1 byte:
+ * netfn_lun and cmd. They're passed to OpenIPMI within an ipmi_smi_msg struct
+ * along with their length.
+ *
+ * ipmi_bt_i2c_msg contains a payload and 4 header fields: the two above in
+ * addition to seq and len. However, len is not included in the length count so
+ * this message encapsulation is considered 1 byte longer than the other.
+ */
+static u8 ipmi_bt_i2c_smi_to_bt_len(u8 smi_msg_len)
+{
+ /* Only field that BT adds to the header is seq. */
+ return smi_msg_len + 1;
+}
+
+static u8 ipmi_bt_i2c_bt_to_smi_len(struct ipmi_bt_i2c_msg *bt_msg)
+{
+ /* Subtract one byte for seq (opposite of above) */
+ return bt_msg->len - 1;
+}
+
+static size_t ipmi_bt_i2c_payload_len(struct ipmi_bt_i2c_msg *bt_msg)
+{
+ /* Subtract one byte for each: netfn_lun, seq, cmd. */
+ return bt_msg->len - 3;
+}
+
+static bool ipmi_bt_i2c_assign_seq(struct ipmi_bt_i2c_master *master,
+ struct ipmi_smi_msg *msg, u8 *ret_seq)
+{
+ struct ipmi_bt_i2c_seq_entry *entry;
+ bool did_cleanup = false;
+ unsigned long flags;
+ u8 seq;
+
+ spin_lock_irqsave(&master->lock, flags);
+retry:
+ for (seq = 0; seq < IPMI_BT_I2C_SEQ_MAX; seq++) {
+ if (!master->seq_msg_map[seq].msg) {
+ master->seq_msg_map[seq].msg = msg;
+ master->seq_msg_map[seq].send_time = jiffies;
+ spin_unlock_irqrestore(&master->lock, flags);
+ *ret_seq = seq;
+ return true;
+ }
+ }
+
+ if (did_cleanup) {
+ spin_unlock_irqrestore(&master->lock, flags);
+ return false;
+ }
+
+ /*
+ * TODO: we should do cleanup at times other than only when we run out
+ * of sequence numbers.
+ */
+ for (seq = 0; seq < IPMI_BT_I2C_SEQ_MAX; seq++) {
+ entry = &master->seq_msg_map[seq];
+ if (entry->msg &&
+ time_after(entry->send_time + IPMI_BT_I2C_TIMEOUT,
+ jiffies)) {
+ __ipmi_bt_i2c_error_reply(master, entry->msg,
+ IPMI_TIMEOUT_ERR);
+ entry->msg = NULL;
+ }
+ }
+ did_cleanup = true;
+ goto retry;
+}
+
+static struct ipmi_smi_msg *ipmi_bt_i2c_find_msg(
+ struct ipmi_bt_i2c_master *master, u8 seq)
+{
+ struct ipmi_smi_msg *msg;
+ unsigned long flags;
+
+ spin_lock_irqsave(&master->lock, flags);
+ msg = master->seq_msg_map[seq].msg;
+ spin_unlock_irqrestore(&master->lock, flags);
+ return msg;
+}
+
+static void ipmi_bt_i2c_free_seq(struct ipmi_bt_i2c_master *master, u8 seq)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&master->lock, flags);
+ master->seq_msg_map[seq].msg = NULL;
+ spin_unlock_irqrestore(&master->lock, flags);
+}
+
+static void ipmi_bt_i2c_send_workfn(struct work_struct *work)
+{
+ struct ipmi_bt_i2c_smi_msg *smi_msg;
+ struct ipmi_bt_i2c_master *master;
+ struct ipmi_bt_i2c_msg bt_msg;
+ struct ipmi_smi_msg *msg;
+ size_t smi_msg_size;
+ unsigned long flags;
+
+ master = container_of(work, struct ipmi_bt_i2c_master,
+ ipmi_bt_i2c_send_work);
+
+ msg = master->msg_to_send;
+ smi_msg_size = msg->data_size;
+ smi_msg = (struct ipmi_bt_i2c_smi_msg *) msg->data;
+
+ if (smi_msg_size > IPMI_BT_I2C_MAX_SMI_SIZE) {
+ ipmi_bt_i2c_error_reply(master, msg, IPMI_REQ_LEN_EXCEEDED_ERR);
+ return;
+ }
+
+ if (smi_msg_size < IPMI_BT_I2C_SMI_MSG_HEADER_SIZE) {
+ ipmi_bt_i2c_error_reply(master, msg, IPMI_REQ_LEN_INVALID_ERR);
+ return;
+ }
+
+ if (!ipmi_bt_i2c_assign_seq(master, msg, &bt_msg.seq)) {
+ ipmi_bt_i2c_error_reply(master, msg, IPMI_NODE_BUSY_ERR);
+ return;
+ }
+
+ bt_msg.len = ipmi_bt_i2c_smi_to_bt_len(smi_msg_size);
+ bt_msg.netfn_lun = smi_msg->netfn_lun;
+ bt_msg.cmd = smi_msg->cmd;
+ memcpy(bt_msg.payload, smi_msg->payload,
+ ipmi_bt_i2c_payload_len(&bt_msg));
+
+ if (ipmi_bt_i2c_send_request(master, &bt_msg) < 0) {
+ ipmi_bt_i2c_free_seq(master, bt_msg.seq);
+ ipmi_bt_i2c_error_reply(master, msg, IPMI_BUS_ERR);
+ }
+
+ spin_lock_irqsave(&master->lock, flags);
+ master->msg_to_send = NULL;
+ spin_unlock_irqrestore(&master->lock, flags);
+}
+
+void ipmi_bt_i2c_recv_workfn(struct work_struct *work)
+{
+ struct ipmi_bt_i2c_smi_msg *smi_msg;
+ struct ipmi_bt_i2c_master *master;
+ struct ipmi_bt_i2c_msg bt_msg;
+ struct ipmi_smi_msg *msg;
+
+ master = container_of(work, struct ipmi_bt_i2c_master,
+ ipmi_bt_i2c_recv_work);
+
+ if (ipmi_bt_i2c_receive_response(master, &bt_msg) < 0)
+ return;
+
+ if (bt_msg.len < IPMI_BT_I2C_LEN_MIN)
+ return;
+
+ msg = ipmi_bt_i2c_find_msg(master, bt_msg.seq);
+ if (!msg)
+ return;
+
+ ipmi_bt_i2c_free_seq(master, bt_msg.seq);
+
+ if (bt_msg.len < IPMI_BT_I2C_RESPONSE_LEN_MIN)
+ ipmi_bt_i2c_error_reply(master, msg, IPMI_ERR_MSG_TRUNCATED);
+
+ msg->rsp_size = ipmi_bt_i2c_bt_to_smi_len(&bt_msg);
+ smi_msg = (struct ipmi_bt_i2c_smi_msg *) msg->rsp;
+ smi_msg->netfn_lun = bt_msg.netfn_lun;
+ smi_msg->cmd = bt_msg.cmd;
+ memcpy(smi_msg->payload, bt_msg.payload,
+ ipmi_bt_i2c_payload_len(&bt_msg));
+ ipmi_smi_msg_received(master->intf, msg);
+}
+
+static void ipmi_bt_i2c_sender(void *data, struct ipmi_smi_msg *msg)
+{
+ struct ipmi_bt_i2c_master *master = data;
+ unsigned long flags;
+
+ spin_lock_irqsave(&master->lock, flags);
+ if (master->msg_to_send) {
+ /*
+ * TODO(benjaminfair): Queue messages to send instead of only
+ * keeping one.
+ */
+ __ipmi_bt_i2c_error_reply(master, msg, IPMI_NODE_BUSY_ERR);
+ } else {
+ master->msg_to_send = msg;
+ schedule_work(&master->ipmi_bt_i2c_send_work);
+ }
+ spin_unlock_irqrestore(&master->lock, flags);
+}
+
+static void ipmi_bt_i2c_request_events(void *data)
+{
+ struct ipmi_bt_i2c_master *master = data;
+
+ schedule_work(&master->ipmi_bt_i2c_recv_work);
+}
+
+static void ipmi_bt_i2c_set_run_to_completion(void *data,
+ bool run_to_completion)
+{
+}
+
+static void ipmi_bt_i2c_poll(void *data)
+{
+ struct ipmi_bt_i2c_master *master = data;
+
+ schedule_work(&master->ipmi_bt_i2c_recv_work);
+}
+
+static struct ipmi_smi_handlers ipmi_bt_i2c_smi_handlers = {
+ .owner = THIS_MODULE,
+ .start_processing = ipmi_bt_i2c_start_processing,
+ .sender = ipmi_bt_i2c_sender,
+ .request_events = ipmi_bt_i2c_request_events,
+ .set_run_to_completion = ipmi_bt_i2c_set_run_to_completion,
+ .poll = ipmi_bt_i2c_poll,
+};
+
+static int ipmi_bt_i2c_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct ipmi_bt_i2c_master *master;
+ int ret;
+
+ master = devm_kzalloc(&client->dev, sizeof(struct ipmi_bt_i2c_master),
+ GFP_KERNEL);
+ if (!master)
+ return -ENOMEM;
+
+ spin_lock_init(&master->lock);
+ INIT_WORK(&master->ipmi_bt_i2c_recv_work, ipmi_bt_i2c_recv_workfn);
+ INIT_WORK(&master->ipmi_bt_i2c_send_work, ipmi_bt_i2c_send_workfn);
+ master->client = client;
+ i2c_set_clientdata(client, master);
+
+ /*
+ * TODO(benjaminfair): read ipmi_device_id from BMC to determine version
+ * information and be able to tell multiple BMCs apart
+ */
+ ret = ipmi_register_smi(&ipmi_bt_i2c_smi_handlers, master,
+ &master->ipmi_id, &client->dev, 0);
+
+ return ret;
+}
+
+static int ipmi_bt_i2c_remove(struct i2c_client *client)
+{
+ struct ipmi_bt_i2c_master *master;
+
+ master = i2c_get_clientdata(client);
+ return ipmi_unregister_smi(master->intf);
+}
+
+static const struct acpi_device_id ipmi_bt_i2c_acpi_id[] = {
+ {"BTMA0001", 0},
+ {},
+};
+MODULE_DEVICE_TABLE(acpi, ipmi_bt_i2c_acpi_id);
+
+static const struct i2c_device_id ipmi_bt_i2c_i2c_id[] = {
+ {"ipmi-bt-i2c", 0},
+ {},
+};
+MODULE_DEVICE_TABLE(i2c, ipmi_bt_i2c_i2c_id);
+
+static struct i2c_driver ipmi_bt_i2c_driver = {
+ .driver = {
+ .name = "ipmi-bt-i2c",
+ .acpi_match_table = ipmi_bt_i2c_acpi_id,
+ },
+ .id_table = ipmi_bt_i2c_i2c_id,
+ .probe = ipmi_bt_i2c_probe,
+ .remove = ipmi_bt_i2c_remove,
+};
+module_i2c_driver(ipmi_bt_i2c_driver);
+
+MODULE_AUTHOR("Brendan Higgins <brendanhiggins at google.com>");
+MODULE_DESCRIPTION("IPMI Block Transfer over I2C.");
+MODULE_LICENSE("GPL v2");
--
2.14.0.rc1.383.gd1ce394fe2-goog
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