Messages in this thread Patch in this message | | | Date | Mon, 10 Oct 2022 08:28:24 +0700 | Subject | Re: [PATCH v10 1/3] ipmi: ssif_bmc: Add SSIF BMC driver | From | Quan Nguyen <> |
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On 07/10/2022 20:26, Graeme Gregory wrote: > > On 04/10/2022 10:31, 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. >> >> Link: >> https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/ >> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com> > > I have been testing this on our hardware and I don't seem to be able to > get this driver working. I was using an older version. > > I have hacked ssifbridged to deal with the change in len from u8 to > unsigned int. > > It works as long as I only ever send SSIF commands, any attempt to read > a response crashes the state machine and the driver never recovers. No > further SSIF comms is possible! (slave doesnt even ACK writes). > > A couple of comments below on possible state machine errors. > > Its possible I am doing something wrong! >
Thanks Graeme for the test and the comments.
What's your testing hardware?
This was tested with Aspeed ast2500 and ast2600 with the patch series [1] below applied.
If you use the same hw, could you pick the series and see if any thing improve ?
[1] https://lore.kernel.org/all/20210616031046.2317-1-quan@os.amperecomputing.com/
>> --- >> v10: >> + None >> >> v9: >> + Fix dependence with I2C subsystem [Randy] >> + Remove useless error handling path [CJ] >> + Update comment for SSIF_ABORTING state [CJ] >> + Fix "unknown type name --u8" [kernel test robot] >> + Fix ssif_bmc_remove() to return void to align with recent kernel >> change [Quan] >> >> v8: >> + Dropped ssif_bmc.h file and move its content to ssif_bmc.c [Corey] >> + Add struct ipmi_ssif_msg to include/uapi/linux/ipmi_ssif_bmc.h >> header file [Corey] >> + Use unsigned int for len field in struct ipmi_ssif_msg [Corey] >> + Avoid using packed structure [Corey] >> + Add comment to clarify the logic flow [Corey] >> + Fix multipart read end with len=0 issue [Corey] >> + Refactor code handle the too big request message [Corey] >> + Fix code indentation issue [Corey] >> + Clean buffer before receiving request to avoid garbage [Quan] >> + Fix the license to SPDX-License-Identifier: GPL-2.0-only [Quan] >> >> 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 | 10 + >> drivers/char/ipmi/Makefile | 1 + >> drivers/char/ipmi/ssif_bmc.c | 873 +++++++++++++++++++++++++++++ >> include/uapi/linux/ipmi_ssif_bmc.h | 18 + >> 4 files changed, 902 insertions(+) >> create mode 100644 drivers/char/ipmi/ssif_bmc.c >> create mode 100644 include/uapi/linux/ipmi_ssif_bmc.h >> >> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig >> index 39565cf74b2c..b6c0d35fc1a5 100644 >> --- a/drivers/char/ipmi/Kconfig >> +++ b/drivers/char/ipmi/Kconfig >> @@ -169,6 +169,16 @@ 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" >> + depends on I2C && 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..a7bb4b99000e >> --- /dev/null >> +++ b/drivers/char/ipmi/ssif_bmc.c >> @@ -0,0 +1,873 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * 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 <linux/ipmi_ssif_bmc.h> >> + >> +#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 >> + >> +/* >> + * 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 */ >> + >> +struct ssif_part_buffer { >> + u8 address; >> + u8 smbus_cmd; >> + u8 length; >> + u8 payload[MAX_PAYLOAD_PER_TRANSACTION]; >> + u8 pec; >> + u8 index; >> +}; >> + >> +/* >> + * 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_ABORTING 0x05 : Aborting state >> + */ >> +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 ipmi_ssif_msg response; >> + struct ipmi_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); >> +} >> + >> +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 ipmi_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, >> + sizeof_field(struct ipmi_ssif_msg, len) + >> ssif_bmc->request.len, >> + sizeof(struct ipmi_ssif_msg))) { >> + spin_unlock_irqrestore(&ssif_bmc->lock, flags); >> + ret = -EINVAL; >> + } else { >> + count = min_t(ssize_t, >> + sizeof_field(struct ipmi_ssif_msg, len) + >> ssif_bmc->request.len, >> + sizeof(struct ipmi_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 ipmi_ssif_msg msg; >> + unsigned long flags; >> + ssize_t ret; >> + >> + if (count > sizeof(struct ipmi_ssif_msg)) >> + return -EINVAL; >> + >> + if (copy_from_user(&msg, buf, count)) >> + return -EFAULT; >> + >> + if (!msg.len || count < sizeof_field(struct ipmi_ssif_msg, len) + >> msg.len) >> + 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 ipmi_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 ipmi_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 = (u8)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) { >> + /* >> + * 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) >> +{ >> + /* >> + * The msg_idx must be 1 when first enter SSIF_REQ_RECVING state >> + * And it would never exceeded 36 bytes included the 32 bytes max >> payload + >> + * the address + the command + the len and the PEC. >> + */ >> + if (ssif_bmc->msg_idx < 1 || ssif_bmc->msg_idx > MAX_TRANSACTION) >> + 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; >> + unsigned int len; >> + >> + 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; >> + >> + fallthrough; >> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE: >> + case SSIF_IPMI_MULTIPART_WRITE_END: >> + len = ssif_bmc->request.len + part->length; >> + /* Do the bound check here, not allow the request len exceed >> 254 bytes */ >> + if (len > IPMI_SSIF_PAYLOAD_MAX) { >> + dev_warn(&ssif_bmc->client->dev, >> + "Warn: Request exceeded 254 bytes, aborting"); >> + /* Request too long, aborting */ >> + ssif_bmc->aborting = true; >> + } else { >> + memcpy(ssif_bmc->request.payload + ssif_bmc->request.len, >> + part->payload, part->length); >> + ssif_bmc->request.len += part->length; >> + } >> + 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; >> + memset(&ssif_bmc->part_buf.payload[0], 0, >> MAX_PAYLOAD_PER_TRANSACTION); >> + >> + 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 || > Is this actually correct? The state machine seems to set this as the > default state and in my testing we seem to always reach here with the > state == SSIF_READY?
The I2C_SLAVE_READ_REQUESTED event is expected to come on SSIF_SMBUS_CMD state where Slave has already received and validated the SMBus command, in this case is the I2C_SLAVE_READ_REQUESTED event if the SMBus command indeed is the READ command. You can see the check supported_read_cmd() below.
If Slave see the I2C_SLAVE_READ_REQUESTED event on other states, it will transition to SSIF_ABORTING state that discard everything until there is a new transaction come.
On READ, the sequence of Slave event should be as below: I2C_SLAVE_WRITE_REQUESTED (addr) => I2C_SLAVE_WRITE_RECEIVED (SMBus cmd) => I2C_SLAVE_READ_REQUESTED (Slave feed the first byte) => I2C_SLAVE_READ_PROCESSED (Slave 2nd byte) => .... => I2C_SLAVE_STOP
>> + 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 || > Same comment as above?
Same here, I2C_SLAVE_READ_PROCESSED is expected to come after the I2C_SLAVE_READ_REQUESTED or other I2C_SLAVE_READ_PROCESSED. ie: when the state is SSIF_RES_SENDING. If it comes when Slave in states other than SSIF_RES_SENDING, the Slave will transition to SSIF_ABORTING state.
>> + 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 : >> + 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) >> + return ret; >> + >> + 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); >> + >> + return ret; >> +} >> + >> +static void 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); >> +} >> + >> +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@os.amperecomputing.com>"); >> +MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>"); >> +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF >> interface."); >> +MODULE_LICENSE("GPL"); >> diff --git a/include/uapi/linux/ipmi_ssif_bmc.h >> b/include/uapi/linux/ipmi_ssif_bmc.h >> new file mode 100644 >> index 000000000000..1c6a753dad08 >> --- /dev/null >> +++ b/include/uapi/linux/ipmi_ssif_bmc.h >> @@ -0,0 +1,18 @@ >> +/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note*/ >> +/* >> + * Copyright (c) 2022, Ampere Computing LLC. >> + */ >> + >> +#ifndef _UAPI_LINUX_IPMI_SSIF_BMC_H >> +#define _UAPI_LINUX_IPMI_SSIF_BMC_H >> + >> +#include <linux/types.h> >> + >> +/* Max length of ipmi ssif message included netfn and cmd field */ >> +#define IPMI_SSIF_PAYLOAD_MAX 254 >> +struct ipmi_ssif_msg { >> + unsigned int len; >> + __u8 payload[IPMI_SSIF_PAYLOAD_MAX]; >> +}; >> + >> +#endif /* _UAPI_LINUX_IPMI_SSIF_BMC_H */
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