On Fri, Apr 22, 2022 at 11:08:01AM +0700, Quan Nguyen wrote: > The SMBus system interface (SSIF) IPMI BMC driver can be used to perform > in-band IPMI communication with their host in management (BMC) side. > > Thanks Dan for the copy_from_user() fix in the link below. This is much better, the handling of lengths and indexes is much easier to understand. I hope you agree. I may be repeating myself on some things, it's been a while since the last submit. So please forgive me if I do. Comments inline... > > Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@xxxxxxxxxxxxxxxxxxxxxx/ > Signed-off-by: Quan Nguyen <quan@xxxxxxxxxxxxxxxxxxxxxx> > --- > v7: > + Remove unneccessary del_timer() in response_timeout() [Corey] > + Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae] > + Add MODULE_DEVICE_TABLE(of, ssif_bmc_match), fix blank line [Jae] > + Dropped the use of ssif_msg_len() macro, use the len directly [Quan] > + Solve possible issue if both response timer and ssif_bmc_write() > occurred at the same time [Corey] > + Fix wrong return type of ssif_bmc_poll() [kernel robot test] > + Refactor and introduce ssif_part_buffer struct to replace the > response_buf to manage each send/receive part of ssif [Quan] > + Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey] > + Support abort feature to skip the current bad request/response and > wait until next new request [Corey] > + Refactor the PEC calculation to avoid the re-calculate the PEC on > each I2C_SLAVE_WRITE_RECEIVED event [Quan] > + Fix the use of error-proned idx [Corey] > + Defer the test for valid SMBus command until the read/write part > is determined [Quan] > + Change/split unsupported_smbus_cmd() to > supported_[write|read]_cmd() [Corey] > + Abort the request if somehow its size exceeded 255 bytes [Quan] > > v6: > + Drop the use of slave_enable() [Wolfram] > + Make i2c-aspeed to issue RxCmdLast command on all > I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan] > + Make i2c slave to return -EBUSY when it's busy [Quan] > + Drop the aborting feature as return Completion Code 0xFF may stop > host to retry and make ipmi_ssif.so fails to load [Quan] > + Add timer to recover slave from busy state when no response [Quan] > + Clean request/response buffer appropriately [Quan] > + Add some minor change on error and warning messages [Quan] > > v5: > + None > > v4: > + Send response with Completion code 0xFF when aborting [Quan] > + Added bounding check on SMBus writes and the whole request [Dan] > + Moved buffer to end of struct ssif_bmc_ctx to avoid context > corruption if somehow buffer is written past the end [Dan] > + Return -EINVAL if userspace buffer too small, dont > silence truncate [Corey, Joel] > + Not necessary to check NONBLOCK in lock [Corey] > + Enforce one user at a time [Joel] > + Reject write with invalid response length from userspace [Corey] > + Add state machines for better ssif bmc state handling [Quan] > + Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic > SSIF BMC driver [Quan] > + Change compatible string "aspeed,ast2500-ssif-bmc" to > "ampere,ssif-bmc" [Quan] > + Abort current request with invalid SMBus write or > invalid command [Quan] > + Abort all request if there is pending response [Quan] > + Changed validate_pec() to validate_request() [Quan] > + Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan] > + Print internal state string for ease investigating issue [Quan] > + Move to READY state on SLAVE_STOP event [Quan] > + Change initilize_transfer() to process_smbus_cmd() [Quan] > + Introduce functions for each slave event [Quan] > > v3: > + Removed redundant license info [Joel] > + Switched to use traditional if-else [Joel] > + Removed unused ssif_bmc_ioctl() [Joel] > + Made handle_request()/complete_response() to return void [Joel] > + Refactored send_ssif_bmc_response() and > receive_ssif_bmc_request() [Corey] > + Removed mutex [Corey] > + Use spin_lock/unlock_irqsave/restore in callback [Corey] > + Removed the unnecessary memset [Corey] > + Switch to use dev_err() [Corey] > > v2: > + Fixed compiling error with COMPILE_TEST for arc > > drivers/char/ipmi/Kconfig | 11 + > drivers/char/ipmi/Makefile | 1 + > drivers/char/ipmi/ssif_bmc.c | 780 +++++++++++++++++++++++++++++++++++ > drivers/char/ipmi/ssif_bmc.h | 107 +++++ > 4 files changed, 899 insertions(+) > create mode 100644 drivers/char/ipmi/ssif_bmc.c > create mode 100644 drivers/char/ipmi/ssif_bmc.h > > diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig > index b061e6b513ed..18a89093d64e 100644 > --- a/drivers/char/ipmi/Kconfig > +++ b/drivers/char/ipmi/Kconfig > @@ -169,6 +169,17 @@ config ASPEED_BT_IPMI_BMC > found on Aspeed SOCs (AST2400 and AST2500). The driver > implements the BMC side of the BT interface. > > +config SSIF_IPMI_BMC > + tristate "SSIF IPMI BMC driver" > + select I2C > + select I2C_SLAVE > + help > + This enables the IPMI SMBus system interface (SSIF) at the > + management (BMC) side. > + > + The driver implements the BMC side of the SMBus system > + interface (SSIF). > + > config IPMB_DEVICE_INTERFACE > tristate 'IPMB Interface handler' > depends on I2C > diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile > index 7ce790efad92..cb6138b8ded9 100644 > --- a/drivers/char/ipmi/Makefile > +++ b/drivers/char/ipmi/Makefile > @@ -30,3 +30,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o > obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o > obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o > obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o > +obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o > diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c > new file mode 100644 > index 000000000000..4cff5e1a075e > --- /dev/null > +++ b/drivers/char/ipmi/ssif_bmc.c > @@ -0,0 +1,780 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * The driver for BMC side of SSIF interface > + * > + * Copyright (c) 2022, Ampere Computing LLC > + * > + */ > + > +#include <linux/i2c.h> > +#include <linux/miscdevice.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/platform_device.h> > +#include <linux/poll.h> > +#include <linux/sched.h> > +#include <linux/mutex.h> > +#include <linux/spinlock.h> > +#include <linux/timer.h> > +#include <linux/jiffies.h> > + > +#include "ssif_bmc.h" > + > +static const char *state_to_string(enum ssif_state state) > +{ > + switch (state) { > + case SSIF_READY: > + return "SSIF_READY"; > + case SSIF_START: > + return "SSIF_START"; > + case SSIF_SMBUS_CMD: > + return "SSIF_SMBUS_CMD"; > + case SSIF_REQ_RECVING: > + return "SSIF_REQ_RECVING"; > + case SSIF_RES_SENDING: > + return "SSIF_RES_SENDING"; > + case SSIF_ABORTING: > + return "SSIF_ABORTING"; > + default: > + return "SSIF_STATE_UNKNOWN"; > + } > +} > + > +/* Handle SSIF message that will be sent to user */ > +static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) > +{ > + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); > + struct ssif_msg msg; > + unsigned long flags; > + ssize_t ret; > + > + spin_lock_irqsave(&ssif_bmc->lock, flags); > + while (!ssif_bmc->request_available) { > + spin_unlock_irqrestore(&ssif_bmc->lock, flags); > + if (file->f_flags & O_NONBLOCK) > + return -EAGAIN; > + ret = wait_event_interruptible(ssif_bmc->wait_queue, > + ssif_bmc->request_available); > + if (ret) > + return ret; > + spin_lock_irqsave(&ssif_bmc->lock, flags); > + } > + > + if (count < min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg))) { > + spin_unlock_irqrestore(&ssif_bmc->lock, flags); > + ret = -EINVAL; > + } else { > + count = min_t(ssize_t, ssif_bmc->request.len + 1, sizeof(struct ssif_msg)); > + memcpy(&msg, &ssif_bmc->request, count); > + ssif_bmc->request_available = false; > + spin_unlock_irqrestore(&ssif_bmc->lock, flags); > + > + ret = copy_to_user(buf, &msg, count); > + } > + > + return (ret < 0) ? ret : count; > +} > + > +/* Handle SSIF message that is written by user */ > +static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count, > + loff_t *ppos) > +{ > + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); > + struct ssif_msg msg; > + unsigned long flags; > + ssize_t ret; > + > + if (count > sizeof(struct ssif_msg)) > + return -EINVAL; > + > + if (copy_from_user(&msg, buf, count)) > + return -EFAULT; > + > + if (!msg.len || count < msg.len + 1) > + return -EINVAL; > + > + spin_lock_irqsave(&ssif_bmc->lock, flags); > + while (ssif_bmc->response_in_progress) { > + spin_unlock_irqrestore(&ssif_bmc->lock, flags); > + if (file->f_flags & O_NONBLOCK) > + return -EAGAIN; > + ret = wait_event_interruptible(ssif_bmc->wait_queue, > + !ssif_bmc->response_in_progress); > + if (ret) > + return ret; > + spin_lock_irqsave(&ssif_bmc->lock, flags); > + } > + > + /* > + * The write must complete before the response timeout fired, otherwise > + * the response is aborted and wait for next request > + * Return -EINVAL if the response is aborted > + */ > + ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL; > + if (ret) > + goto exit; > + > + del_timer(&ssif_bmc->response_timer); > + ssif_bmc->response_timer_inited = false; > + > + memcpy(&ssif_bmc->response, &msg, count); > + ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION); > + > + ssif_bmc->response_in_progress = true; > + > + /* ssif_bmc not busy */ > + ssif_bmc->busy = false; > + > + /* Clean old request buffer */ > + memset(&ssif_bmc->request, 0, sizeof(struct ssif_msg)); > +exit: > + spin_unlock_irqrestore(&ssif_bmc->lock, flags); > + > + return (ret < 0) ? ret : count; > +} > + > +static int ssif_bmc_open(struct inode *inode, struct file *file) > +{ > + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); > + int ret = 0; > + > + spin_lock_irq(&ssif_bmc->lock); > + if (!ssif_bmc->running) > + ssif_bmc->running = 1; > + else > + ret = -EBUSY; > + spin_unlock_irq(&ssif_bmc->lock); > + > + return ret; > +} > + > +static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait) > +{ > + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); > + __poll_t mask = 0; > + > + poll_wait(file, &ssif_bmc->wait_queue, wait); > + > + spin_lock_irq(&ssif_bmc->lock); > + /* The request is available, userspace application can get the request */ > + if (ssif_bmc->request_available) > + mask |= POLLIN; > + > + spin_unlock_irq(&ssif_bmc->lock); > + > + return mask; > +} > + > +static int ssif_bmc_release(struct inode *inode, struct file *file) > +{ > + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); > + > + spin_lock_irq(&ssif_bmc->lock); > + ssif_bmc->running = 0; > + spin_unlock_irq(&ssif_bmc->lock); > + > + return 0; > +} > + > +/* > + * System calls to device interface for user apps > + */ > +static const struct file_operations ssif_bmc_fops = { > + .owner = THIS_MODULE, > + .open = ssif_bmc_open, > + .read = ssif_bmc_read, > + .write = ssif_bmc_write, > + .release = ssif_bmc_release, > + .poll = ssif_bmc_poll, > +}; > + > +/* Called with ssif_bmc->lock held. */ > +static void complete_response(struct ssif_bmc_ctx *ssif_bmc) > +{ > + /* Invalidate response in buffer to denote it having been sent. */ > + ssif_bmc->response.len = 0; > + ssif_bmc->response_in_progress = false; > + ssif_bmc->nbytes_processed = 0; > + ssif_bmc->remain_len = 0; > + ssif_bmc->busy = false; > + memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer)); > + wake_up_all(&ssif_bmc->wait_queue); > +} > + > +static void response_timeout(struct timer_list *t) > +{ > + struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer); > + unsigned long flags; > + > + spin_lock_irqsave(&ssif_bmc->lock, flags); > + > + /* Do nothing if the response is in progress */ > + if (!ssif_bmc->response_in_progress) { > + /* Recover ssif_bmc from busy */ > + ssif_bmc->busy = false; > + ssif_bmc->response_timer_inited = false; > + /* Set aborting flag */ > + ssif_bmc->aborting = true; > + } > + > + spin_unlock_irqrestore(&ssif_bmc->lock, flags); > +} > + > +/* Called with ssif_bmc->lock held. */ > +static void handle_request(struct ssif_bmc_ctx *ssif_bmc) > +{ > + /* set ssif_bmc to busy waiting for response */ > + ssif_bmc->busy = true; > + /* Request message is available to process */ > + ssif_bmc->request_available = true; > + /* Clean old response buffer */ > + memset(&ssif_bmc->response, 0, sizeof(struct ssif_msg)); > + /* This is the new READ request.*/ > + wake_up_all(&ssif_bmc->wait_queue); > + > + /* Armed timer to recover slave from busy state in case of no response */ > + if (!ssif_bmc->response_timer_inited) { > + timer_setup(&ssif_bmc->response_timer, response_timeout, 0); > + ssif_bmc->response_timer_inited = true; > + } > + mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT)); > +} > + > +static void calculate_response_part_pec(struct ssif_part_buffer *part) > +{ > + u8 addr = part->address; > + > + /* PEC - Start Read Address */ > + part->pec = i2c_smbus_pec(0, &addr, 1); > + /* PEC - SSIF Command */ > + part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1); > + /* PEC - Restart Write Address */ > + addr = addr | 0x01; > + part->pec = i2c_smbus_pec(part->pec, &addr, 1); > + part->pec = i2c_smbus_pec(part->pec, &part->length, 1); > + if (part->length) > + part->pec = i2c_smbus_pec(part->pec, part->payload, part->length); > +} > + > +static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc) > +{ > + struct ssif_part_buffer *part = &ssif_bmc->part_buf; > + > + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr); > + part->length = ssif_bmc->response.len; > + > + /* Clear the rest to 0 */ > + memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length); > + memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length); > +} > + > +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc) > +{ > + struct ssif_part_buffer *part = &ssif_bmc->part_buf; > + u8 part_len = 0; > + > + part->address = GET_8BIT_ADDR(ssif_bmc->client->addr); > + switch (part->smbus_cmd) { > + case SSIF_IPMI_MULTIPART_READ_START: > + /* > + * Read Start length is 32 bytes. > + * Read Start transfer first 30 bytes of IPMI response > + * and 2 special code 0x00, 0x01. > + */ > + ssif_bmc->nbytes_processed = 0; > + ssif_bmc->block_num = 0; > + part->length = MAX_PAYLOAD_PER_TRANSACTION; > + part_len = MAX_IPMI_DATA_PER_START_TRANSACTION; > + ssif_bmc->remain_len = ssif_bmc->response.len - part_len; > + > + part->payload[0] = 0x00; /* Start Flag */ > + part->payload[1] = 0x01; /* Start Flag */ > + > + memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len); > + break; > + > + case SSIF_IPMI_MULTIPART_READ_MIDDLE: > + /* > + * IPMI READ Middle or READ End messages can carry up to 31 bytes > + * IPMI data plus block number byte. > + */ > + if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) { Shouldn't this be <=? If you were sending something that was exactly 94 bytes, for instance, you should have a 32-byte start, a 31-byte middle, and a 31-byte end. If you don't have <= here, you would have a start, two 31-byte middles, and a zero-length end, which is forbidden by the spec. > + /* > + * This is READ End message > + * Return length is the remaining response data length > + * plus block number > + * Block number 0xFF is to indicate this is last message > + * > + */ > + /* Clean the buffer */ > + memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION); > + part->length = ssif_bmc->remain_len + 1; > + part_len = ssif_bmc->remain_len; > + ssif_bmc->block_num = 0xFF; > + part->payload[0] = ssif_bmc->block_num; > + } else { > + /* > + * This is READ Middle message > + * Response length is the maximum SMBUS transfer length > + * Block number byte is incremented > + * Return length is maximum SMBUS transfer length > + */ > + part->length = MAX_PAYLOAD_PER_TRANSACTION; > + part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION; > + part->payload[0] = ssif_bmc->block_num; > + ssif_bmc->block_num++; > + } > + > + ssif_bmc->remain_len -= part_len; > + memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed, > + part_len); > + break; > + > + default: > + /* Do not expect to go to this case */ > + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n", > + __func__, part->smbus_cmd); > + break; > + } > + > + ssif_bmc->nbytes_processed += part_len; > +} > + > +static bool supported_read_cmd(u8 cmd) > +{ > + if (cmd == SSIF_IPMI_SINGLEPART_READ || > + cmd == SSIF_IPMI_MULTIPART_READ_START || > + cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE) > + return true; > + > + return false; > +} > + > +static bool supported_write_cmd(u8 cmd) > +{ > + if (cmd == SSIF_IPMI_SINGLEPART_WRITE || > + cmd == SSIF_IPMI_MULTIPART_WRITE_START || > + cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE || > + cmd == SSIF_IPMI_MULTIPART_WRITE_END) > + return true; > + > + return false; > +} > + > +/* Process the IPMI response that will be read by master */ > +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val) > +{ > + struct ssif_part_buffer *part = &ssif_bmc->part_buf; > + > + /* msg_idx start from 0 */ > + if (part->index < part->length) > + *val = part->payload[part->index]; > + else if (part->index == part->length && ssif_bmc->pec_support) > + *val = part->pec; > + else > + *val = 0; > + > + part->index++; > +} > + > +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val) > +{ > + /* msg_idx should not be 0 when reach here */ > + if (!ssif_bmc->msg_idx || ssif_bmc->msg_idx > MAX_TRANSACTION) Should be >= 0 here? If not, (PEC maybe?) you should document why, because it raises red flags. > + return; > + > + if (ssif_bmc->msg_idx == 1) { > + ssif_bmc->part_buf.length = *val; > + ssif_bmc->part_buf.index = 0; > + } else { > + ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val; > + } > + > + ssif_bmc->msg_idx++; > +} > + > +static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc) > +{ > + struct ssif_part_buffer *part = &ssif_bmc->part_buf; > + bool ret = true; > + u8 cpec; > + u8 addr; > + > + if (part->index == part->length) { > + /* PEC is not included */ > + ssif_bmc->pec_support = false; > + ret = true; > + goto exit; > + } > + > + if (part->index != part->length + 1) { > + ret = false; > + goto exit; > + } > + > + /* PEC is included */ > + ssif_bmc->pec_support = true; > + part->pec = part->payload[part->length]; > + addr = GET_8BIT_ADDR(ssif_bmc->client->addr); > + cpec = i2c_smbus_pec(0, &addr, 1); > + cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1); > + cpec = i2c_smbus_pec(cpec, &part->length, 1); > + /* > + * As SMBus specification does not allow the length > + * (byte count) in the Write-Block protocol to be zero. > + * Therefore, it is illegal to have the last Middle > + * transaction in the sequence carry 32-byte and have > + * a length of ‘0’ in the End transaction. > + * But some users may try to use this way and we should > + * prevent ssif_bmc driver broken in this case. > + */ > + if (part->length) > + cpec = i2c_smbus_pec(cpec, part->payload, part->length); > + > + if (cpec != part->pec) > + ret = false; > + > +exit: > + return ret; > +} > + > +static void process_request_part(struct ssif_bmc_ctx *ssif_bmc) > +{ > + struct ssif_part_buffer *part = &ssif_bmc->part_buf; > + > + switch (part->smbus_cmd) { > + case SSIF_IPMI_SINGLEPART_WRITE: > + /* save the whole part to request*/ > + ssif_bmc->request.len = part->length; > + memcpy(ssif_bmc->request.payload, part->payload, part->length); > + > + break; > + case SSIF_IPMI_MULTIPART_WRITE_START: > + ssif_bmc->request.len = 0; Spacing issue here. You need to run patches through checkpatch.pl before submitting them. Also, the empty lines here and above are inconsistent with the rest of the file. > + > + fallthrough; > + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE: > + case SSIF_IPMI_MULTIPART_WRITE_END: > + /* Do the bound check here, not allow the request len exceed 254 bytes */ > + if (ssif_bmc->request.len <= MSG_PAYLOAD_LEN_MAX - part->length) { Again, the <= is not normal for this check. If it's correct, it needs to be documented. > + memcpy(ssif_bmc->request.payload + ssif_bmc->request.len, > + part->payload, part->length); > + ssif_bmc->request.len += part->length; > + } else { > + dev_warn(&ssif_bmc->client->dev, > + "Warn: Request exceeded 254 bytes, aborting"); > + /* Request too long, aborting */ > + ssif_bmc->aborting = true; > + } > + break; > + default: > + /* Do not expect to go to this case */ > + dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n", > + __func__, part->smbus_cmd); > + break; > + } > +} > + > +static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val) > +{ > + /* SMBUS command can vary (single or multi-part) */ > + ssif_bmc->part_buf.smbus_cmd = *val; > + ssif_bmc->msg_idx = 1; > + > + if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) { > + /* > + * The response maybe not come in-time, causing host SSIF driver > + * to timeout and resend a new request. In such case check for > + * pending response and clear it > + */ > + if (ssif_bmc->response_in_progress) > + complete_response(ssif_bmc); > + > + /* This is new request, flip aborting flag if set */ > + if (ssif_bmc->aborting) > + ssif_bmc->aborting = false; > + } > +} > + > +static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val) > +{ > + if (ssif_bmc->state == SSIF_READY || > + ssif_bmc->state == SSIF_START || > + ssif_bmc->state == SSIF_REQ_RECVING || > + ssif_bmc->state == SSIF_RES_SENDING) { > + dev_warn(&ssif_bmc->client->dev, > + "Warn: %s unexpected READ REQUESTED in state=%s\n", > + __func__, state_to_string(ssif_bmc->state)); > + ssif_bmc->state = SSIF_ABORTING; > + *val = 0; > + return; > + > + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) { > + if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) { > + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x", > + ssif_bmc->part_buf.smbus_cmd); > + ssif_bmc->aborting = true; > + } > + > + if (ssif_bmc->aborting) > + ssif_bmc->state = SSIF_ABORTING; > + else > + ssif_bmc->state = SSIF_RES_SENDING; > + } > + > + ssif_bmc->msg_idx = 0; > + > + /* Send 0 if there is nothing to send */ > + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) { > + *val = 0; > + return; > + } > + > + if (ssif_bmc->is_singlepart_read) > + set_singlepart_response_buffer(ssif_bmc); > + else > + set_multipart_response_buffer(ssif_bmc); > + > + calculate_response_part_pec(&ssif_bmc->part_buf); > + ssif_bmc->part_buf.index = 0; > + *val = ssif_bmc->part_buf.length; > +} > + > +static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val) > +{ > + if (ssif_bmc->state == SSIF_READY || > + ssif_bmc->state == SSIF_START || > + ssif_bmc->state == SSIF_REQ_RECVING || > + ssif_bmc->state == SSIF_SMBUS_CMD) { > + dev_warn(&ssif_bmc->client->dev, > + "Warn: %s unexpected READ PROCESSED in state=%s\n", > + __func__, state_to_string(ssif_bmc->state)); > + ssif_bmc->state = SSIF_ABORTING; > + *val = 0; > + return; > + } > + > + /* Send 0 if there is nothing to send */ > + if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) { > + *val = 0; > + return; > + } > + > + handle_read_processed(ssif_bmc, val); > +} > + > +static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val) > +{ > + if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) { > + ssif_bmc->state = SSIF_START; > + > + } else if (ssif_bmc->state == SSIF_START || > + ssif_bmc->state == SSIF_REQ_RECVING || > + ssif_bmc->state == SSIF_RES_SENDING) { > + dev_warn(&ssif_bmc->client->dev, > + "Warn: %s unexpected WRITE REQUEST in state=%s\n", > + __func__, state_to_string(ssif_bmc->state)); > + ssif_bmc->state = SSIF_ABORTING; > + return; > + } > + > + ssif_bmc->msg_idx = 0; > + ssif_bmc->part_buf.address = *val; > +} > + > +static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val) > +{ > + if (ssif_bmc->state == SSIF_READY || > + ssif_bmc->state == SSIF_RES_SENDING) { > + dev_warn(&ssif_bmc->client->dev, > + "Warn: %s unexpected WRITE RECEIVED in state=%s\n", > + __func__, state_to_string(ssif_bmc->state)); > + ssif_bmc->state = SSIF_ABORTING; > + > + } else if (ssif_bmc->state == SSIF_START) { > + ssif_bmc->state = SSIF_SMBUS_CMD; > + > + } else if (ssif_bmc->state == SSIF_SMBUS_CMD) { > + if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) { > + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x", > + ssif_bmc->part_buf.smbus_cmd); > + ssif_bmc->aborting = true; > + } > + > + if (ssif_bmc->aborting) > + ssif_bmc->state = SSIF_ABORTING; > + else > + ssif_bmc->state = SSIF_REQ_RECVING; > + } > + > + /* This is response sending state */ > + if (ssif_bmc->state == SSIF_REQ_RECVING) > + handle_write_received(ssif_bmc, val); > + else if (ssif_bmc->state == SSIF_SMBUS_CMD) > + process_smbus_cmd(ssif_bmc, val); > +} > + > +static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val) > +{ > + if (ssif_bmc->state == SSIF_READY || > + ssif_bmc->state == SSIF_START || > + ssif_bmc->state == SSIF_SMBUS_CMD || > + ssif_bmc->state == SSIF_ABORTING) { > + dev_warn(&ssif_bmc->client->dev, > + "Warn: %s unexpected SLAVE STOP in state=%s\n", > + __func__, state_to_string(ssif_bmc->state)); > + ssif_bmc->state = SSIF_READY; > + > + } else if (ssif_bmc->state == SSIF_REQ_RECVING) { > + if (validate_request_part(ssif_bmc)) { > + process_request_part(ssif_bmc); > + if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE || > + ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END) > + handle_request(ssif_bmc); > + ssif_bmc->state = SSIF_READY; > + } else { > + /* > + * A BMC that receives an invalid request drop the data for the write > + * transaction and any further transactions (read or write) until > + * the next valid read or write Start transaction is received > + */ > + dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n"); > + ssif_bmc->aborting = true; > + } > + } else if (ssif_bmc->state == SSIF_RES_SENDING) { > + if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF) > + /* Invalidate response buffer to denote it is sent */ > + complete_response(ssif_bmc); > + ssif_bmc->state = SSIF_READY; > + } > + > + /* Reset message index */ > + ssif_bmc->msg_idx = 0; > +} > + > +/* > + * Callback function to handle I2C slave events > + */ > +static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val) > +{ > + unsigned long flags; > + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client); > + int ret = 0; > + > + spin_lock_irqsave(&ssif_bmc->lock, flags); > + > + switch (event) { > + case I2C_SLAVE_READ_REQUESTED: > + on_read_requested_event(ssif_bmc, val); > + break; > + > + case I2C_SLAVE_WRITE_REQUESTED: > + on_write_requested_event(ssif_bmc, val); > + break; > + > + case I2C_SLAVE_READ_PROCESSED: > + on_read_processed_event(ssif_bmc, val); > + break; > + > + case I2C_SLAVE_WRITE_RECEIVED: > + on_write_received_event(ssif_bmc, val); > + break; > + > + case I2C_SLAVE_STOP: > + on_stop_event(ssif_bmc, val); > + break; > + > + default: > + dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n"); > + break; > + } > + > + if (!ssif_bmc->aborting && ssif_bmc->busy) > + ret = -EBUSY; > + > + spin_unlock_irqrestore(&ssif_bmc->lock, flags); > + > + return ret; > +} > + > +static int ssif_bmc_probe(struct i2c_client *client, const struct i2c_device_id *id) > +{ > + struct ssif_bmc_ctx *ssif_bmc; > + int ret; > + > + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL); > + if (!ssif_bmc) > + return -ENOMEM; > + > + spin_lock_init(&ssif_bmc->lock); > + > + init_waitqueue_head(&ssif_bmc->wait_queue); > + ssif_bmc->request_available = false; > + ssif_bmc->response_in_progress = false; > + ssif_bmc->busy = false; > + ssif_bmc->response_timer_inited = false; > + > + /* Register misc device interface */ > + ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR; > + ssif_bmc->miscdev.name = DEVICE_NAME; > + ssif_bmc->miscdev.fops = &ssif_bmc_fops; > + ssif_bmc->miscdev.parent = &client->dev; > + ret = misc_register(&ssif_bmc->miscdev); > + if (ret) > + goto out; > + > + ssif_bmc->client = client; > + ssif_bmc->client->flags |= I2C_CLIENT_SLAVE; > + > + /* Register I2C slave */ > + i2c_set_clientdata(client, ssif_bmc); > + ret = i2c_slave_register(client, ssif_bmc_cb); > + if (ret) { > + misc_deregister(&ssif_bmc->miscdev); > + goto out; > + } > + > + return 0; > +out: > + devm_kfree(&client->dev, ssif_bmc); > + return ret; > +} > + > +static int ssif_bmc_remove(struct i2c_client *client) > +{ > + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client); > + > + i2c_slave_unregister(client); > + misc_deregister(&ssif_bmc->miscdev); > + > + return 0; > +} > + > +static const struct of_device_id ssif_bmc_match[] = { > + { .compatible = "ssif-bmc" }, > + { }, > +}; > +MODULE_DEVICE_TABLE(of, ssif_bmc_match); > + > +static const struct i2c_device_id ssif_bmc_id[] = { > + { DEVICE_NAME, 0 }, > + { }, > +}; > +MODULE_DEVICE_TABLE(i2c, ssif_bmc_id); > + > +static struct i2c_driver ssif_bmc_driver = { > + .driver = { > + .name = DEVICE_NAME, > + .of_match_table = ssif_bmc_match, > + }, > + .probe = ssif_bmc_probe, > + .remove = ssif_bmc_remove, > + .id_table = ssif_bmc_id, > +}; > + > +module_i2c_driver(ssif_bmc_driver); > + > +MODULE_AUTHOR("Quan Nguyen <quan@xxxxxxxxxxxxxxxxxxxxxx>"); > +MODULE_AUTHOR("Chuong Tran <chuong@xxxxxxxxxxxxxxxxxxxxxx>"); > +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface."); > +MODULE_LICENSE("GPL"); > diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h > new file mode 100644 > index 000000000000..2c3fc2a4698f > --- /dev/null > +++ b/drivers/char/ipmi/ssif_bmc.h > @@ -0,0 +1,107 @@ > +/* SPDX-License-Identifier: GPL-2.0+ */ > +/* > + * The driver for BMC side of SSIF interface > + * > + * Copyright (c) 2022, Ampere Computing LLC > + * > + */ > +#ifndef __SSIF_BMC_H__ > +#define __SSIF_BMC_H__ > + Is there any value in having a separate .h file for this? Unless you want to share something with the IPMI host side, which might make sense on some of the message numbers, but not a big deal, and even then you could put the .h file with the .c files. Except for the userspace API, which I will address later. > +#define DEVICE_NAME "ipmi-ssif-host" > + > +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff) > + > +/* A standard SMBus Transaction is limited to 32 data bytes */ > +#define MAX_PAYLOAD_PER_TRANSACTION 32 > +/* Transaction includes the address, the command, the length and the PEC byte */ > +#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4) > + > +#define MAX_IPMI_DATA_PER_START_TRANSACTION 30 > +#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31 > + > +#define SSIF_IPMI_SINGLEPART_WRITE 0x2 > +#define SSIF_IPMI_SINGLEPART_READ 0x3 > +#define SSIF_IPMI_MULTIPART_WRITE_START 0x6 > +#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7 > +#define SSIF_IPMI_MULTIPART_WRITE_END 0x8 > +#define SSIF_IPMI_MULTIPART_READ_START 0x3 > +#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9 > + > +/* Include netfn and cmd field */ > +#define MSG_PAYLOAD_LEN_MAX 254 > +/* > + * IPMI 2.0 Spec, section 12.7 SSIF Timing, > + * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms > + * Recover ssif_bmc from busy state if it takes up to 500ms > + */ > +#define RESPONSE_TIMEOUT 500 /* ms */ > + I seem to remember mentioning this before, but there is no reason to pack the structures below. And second, the following is a userspace API structures, so it needs to be in its own file in include/uapi/linux, along with any supporting things that users will need to use. And your userspace code should be using that file. > +struct ssif_msg { > + u8 len; Just to be 100% safe, it might be better to use a u16 on this. The spec sort of limits this to 255 bytes, but it also sort of leaves it open to be larger. > + u8 payload[MSG_PAYLOAD_LEN_MAX]; > +} __packed; > + > +struct ssif_part_buffer { > + u8 address; > + u8 smbus_cmd; > + u8 length; > + u8 payload[MAX_PAYLOAD_PER_TRANSACTION]; > + u8 pec; > + u8 index; > +} __packed; > + > +/* > + * SSIF internal states: > + * SSIF_READY 0x00 : Ready state > + * SSIF_START 0x01 : Start smbus transaction > + * SSIF_SMBUS_CMD 0x02 : Received SMBus command > + * SSIF_REQ_RECVING 0x03 : Receiving request > + * SSIF_RES_SENDING 0x04 : Sending response > + * SSIF_BAD_SMBUS 0x05 : Bad SMbus transaction > + */ > +enum ssif_state { > + SSIF_READY, > + SSIF_START, > + SSIF_SMBUS_CMD, > + SSIF_REQ_RECVING, > + SSIF_RES_SENDING, > + SSIF_ABORTING, > + SSIF_STATE_MAX > +}; > + > +struct ssif_bmc_ctx { > + struct i2c_client *client; > + struct miscdevice miscdev; > + int msg_idx; > + bool pec_support; > + /* ssif bmc spinlock */ > + spinlock_t lock; > + wait_queue_head_t wait_queue; > + u8 running; > + enum ssif_state state; > + /* Timeout waiting for response */ > + struct timer_list response_timer; > + bool response_timer_inited; > + /* Flag to identify a Multi-part Read Transaction */ > + bool is_singlepart_read; > + u8 nbytes_processed; > + u8 remain_len; > + u8 recv_len; > + /* Block Number of a Multi-part Read Transaction */ > + u8 block_num; > + bool request_available; > + bool response_in_progress; > + bool busy; > + bool aborting; > + /* Buffer for SSIF Transaction part*/ > + struct ssif_part_buffer part_buf; > + struct ssif_msg response; > + struct ssif_msg request; > +}; > + > +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file) > +{ > + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev); > +} > +#endif /* __SSIF_BMC_H__ */ > -- > 2.35.1 > >
