From mboxrd@z Thu Jan 1 00:00:00 1970 From: Quan Nguyen Date: Thu, 20 May 2021 21:19:21 +0700 Subject: [PATCH v3 2/7] ipmi: ssif_bmc: Add SSIF BMC driver In-Reply-To: <20210519123042.GF2921206@minyard.net> References: <20210519074934.20712-1-quan@os.amperecomputing.com> <20210519074934.20712-3-quan@os.amperecomputing.com> <20210519123042.GF2921206@minyard.net> Message-ID: List-Id: To: linux-aspeed@lists.ozlabs.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On 19/05/2021 19:30, Corey Minyard wrote: > On Wed, May 19, 2021 at 02:49:29PM +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. >> >> Signed-off-by: Quan Nguyen >> --- >> 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()/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 | 605 +++++++++++++++++++++++++++++++++++ >> drivers/char/ipmi/ssif_bmc.h | 93 ++++++ >> 4 files changed, 710 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 07847d9a459a..ad5c5161bcd6 100644 >> --- a/drivers/char/ipmi/Kconfig >> +++ b/drivers/char/ipmi/Kconfig >> @@ -133,6 +133,17 @@ 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 0822adc2ec41..d04a214d74c4 100644 >> --- a/drivers/char/ipmi/Makefile >> +++ b/drivers/char/ipmi/Makefile >> @@ -27,3 +27,4 @@ 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..d0ea7059b1db >> --- /dev/null >> +++ b/drivers/char/ipmi/ssif_bmc.c >> @@ -0,0 +1,605 @@ >> +// SPDX-License-Identifier: GPL-2.0+ >> +/* >> + * The driver for BMC side of SSIF interface >> + * >> + * Copyright (c) 2021, Ampere Computing LLC >> + * >> + */ >> + >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> + >> +#include "ssif_bmc.h" >> + >> +/* 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) { >> + if (file->f_flags & O_NONBLOCK) { > > There is no real need to check this under the lock. It would simplify > the end of this function if you checked this outside the lock. > Thanks for your reviewing. Will apply change like below in next version: spin_lock_irqsave(&ssif_bmc->lock, flags); while (!ssif_bmc->request_available) { - if (file->f_flags & O_NONBLOCK) { - ret = -EAGAIN; - goto out_unlock; - } 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) >> + ret = -EAGAIN; >> + goto out_unlock; >> + } >> + spin_unlock_irqrestore(&ssif_bmc->lock, flags); >> + ret = wait_event_interruptible(ssif_bmc->wait_queue, >> + ssif_bmc->request_available); >> + if (ret) >> + return ret; >> + spin_lock_irqsave(&ssif_bmc->lock, flags); >> + } >> + >> + count = min_t(ssize_t, ssif_msg_len(&ssif_bmc->request), >> + min_t(ssize_t, sizeof(struct ssif_msg), count)); > > Just curious, what happens if userland supplies a buffer that is too > small? Is data lost? In that case, I would think returning an error > here would be the better thing, as opposed to silently truncating the > message. > Will return -EINVAL if buffer is too small in next version >> + 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); >> + goto out; >> + >> +out_unlock: >> + spin_unlock_irqrestore(&ssif_bmc->lock, flags); >> +out: >> + 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; >> + >> + ret = copy_from_user(&msg, buf, count); >> + if (ret) >> + return ret; >> + >> + if (!msg.len || count < ssif_msg_len(&msg)) >> + return -EINVAL; >> + >> + spin_lock_irqsave(&ssif_bmc->lock, flags); >> + while (ssif_bmc->response_in_progress) { >> + if (file->f_flags & O_NONBLOCK) { > > Same comment as O_NONBLOCK before. > Will apply this follow the above in ssif_bmc_read() >> + ret = -EAGAIN; >> + goto out_unlock; >> + } >> + spin_unlock_irqrestore(&ssif_bmc->lock, flags); >> + ret = wait_event_interruptible(ssif_bmc->wait_queue, >> + !ssif_bmc->response_in_progress); >> + if (ret) >> + goto out; >> + spin_lock_irqsave(&ssif_bmc->lock, flags); >> + } >> + >> + memcpy(&ssif_bmc->response, &msg, count); >> + ssif_bmc->is_singlepart_read = (ssif_msg_len(&msg) <= MAX_PAYLOAD_PER_TRANSACTION + 1); >> + ssif_bmc->response_in_progress = true; >> + if (ssif_bmc->set_ssif_bmc_status) >> + ssif_bmc->set_ssif_bmc_status(ssif_bmc, SSIF_BMC_READY); >> + >> +out_unlock: >> + spin_unlock_irqrestore(&ssif_bmc->lock, flags); >> + >> +out: >> + 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 unsigned int ssif_bmc_poll(struct file *file, poll_table *wait) >> +{ >> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); >> + unsigned int mask = 0; >> + >> + poll_wait(file, &ssif_bmc->wait_queue, wait); >> + >> + spin_lock_irq(&ssif_bmc->lock); >> + /* >> + * The request message is now available so 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 handle_request(struct ssif_bmc_ctx *ssif_bmc) >> +{ >> + if (ssif_bmc->set_ssif_bmc_status) >> + ssif_bmc->set_ssif_bmc_status(ssif_bmc, SSIF_BMC_BUSY); >> + >> + /* Request message is available to process */ >> + ssif_bmc->request_available = true; >> + /* >> + * This is the new READ request. >> + */ >> + wake_up_all(&ssif_bmc->wait_queue); >> +} >> + >> +/* 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; >> + wake_up_all(&ssif_bmc->wait_queue); >> +} >> + >> +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc, u8 *val) >> +{ >> + u8 response_len = 0; >> + int idx = 0; >> + u8 data_len; >> + >> + data_len = ssif_bmc->response.len; >> + switch (ssif_bmc->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. >> + */ >> + *val = MAX_PAYLOAD_PER_TRANSACTION; >> + ssif_bmc->remain_len = data_len - MAX_IPMI_DATA_PER_START_TRANSACTION; >> + ssif_bmc->block_num = 0; >> + >> + ssif_bmc->response_buf[idx++] = 0x00; /* Start Flag */ >> + ssif_bmc->response_buf[idx++] = 0x01; /* Start Flag */ >> + ssif_bmc->response_buf[idx++] = ssif_bmc->response.netfn_lun; >> + ssif_bmc->response_buf[idx++] = ssif_bmc->response.cmd; >> + ssif_bmc->response_buf[idx++] = ssif_bmc->response.payload[0]; >> + >> + response_len = MAX_PAYLOAD_PER_TRANSACTION - idx; >> + >> + memcpy(&ssif_bmc->response_buf[idx], &ssif_bmc->response.payload[1], >> + response_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 >> + * >> + */ >> + *val = ssif_bmc->remain_len + 1; >> + ssif_bmc->block_num = 0xFF; >> + ssif_bmc->response_buf[idx++] = ssif_bmc->block_num; >> + response_len = ssif_bmc->remain_len; >> + /* Clean the buffer */ >> + memset(&ssif_bmc->response_buf[idx], 0, MAX_PAYLOAD_PER_TRANSACTION - idx); >> + } 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 >> + */ >> + *val = MAX_PAYLOAD_PER_TRANSACTION; >> + ssif_bmc->remain_len -= MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION; >> + response_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION; >> + ssif_bmc->response_buf[idx++] = ssif_bmc->block_num; >> + ssif_bmc->block_num++; >> + } >> + >> + memcpy(&ssif_bmc->response_buf[idx], >> + ssif_bmc->response.payload + 1 + ssif_bmc->nbytes_processed, >> + response_len); >> + break; >> + >> + default: >> + /* Do not expect to go to this case */ >> + dev_err(&ssif_bmc->client->dev, >> + "Error: Unexpected SMBus command received 0x%x\n", ssif_bmc->smbus_cmd); >> + break; >> + } >> + >> + ssif_bmc->nbytes_processed += response_len; >> +} >> + >> +/* Process the IPMI response that will be read by master */ >> +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val) >> +{ >> + u8 *buf; >> + u8 pec_len, addr, len; >> + u8 pec = 0; >> + >> + pec_len = ssif_bmc->pec_support ? 1 : 0; >> + /* PEC - Start Read Address */ >> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr); >> + pec = i2c_smbus_pec(pec, &addr, 1); >> + /* PEC - SSIF Command */ >> + pec = i2c_smbus_pec(pec, &ssif_bmc->smbus_cmd, 1); >> + /* PEC - Restart Write Address */ >> + addr = addr | 0x01; >> + pec = i2c_smbus_pec(pec, &addr, 1); >> + >> + if (ssif_bmc->is_singlepart_read) { >> + /* Single-part Read processing */ >> + buf = (u8 *)&ssif_bmc->response; >> + >> + if (ssif_bmc->response.len && ssif_bmc->msg_idx < ssif_bmc->response.len) { >> + ssif_bmc->msg_idx++; >> + *val = buf[ssif_bmc->msg_idx]; >> + } else if (ssif_bmc->response.len && ssif_bmc->msg_idx == ssif_bmc->response.len) { >> + ssif_bmc->msg_idx++; >> + *val = i2c_smbus_pec(pec, buf, ssif_msg_len(&ssif_bmc->response)); >> + } else { >> + *val = 0; >> + } >> + /* Invalidate response buffer to denote it is sent */ >> + if (ssif_bmc->msg_idx + 1 >= (ssif_msg_len(&ssif_bmc->response) + pec_len)) >> + complete_response(ssif_bmc); >> + } else { >> + /* Multi-part Read processing */ >> + switch (ssif_bmc->smbus_cmd) { >> + case SSIF_IPMI_MULTIPART_READ_START: >> + case SSIF_IPMI_MULTIPART_READ_MIDDLE: >> + buf = (u8 *)&ssif_bmc->response_buf; >> + *val = buf[ssif_bmc->msg_idx]; >> + ssif_bmc->msg_idx++; >> + break; >> + default: >> + /* Do not expect to go to this case */ >> + dev_err(&ssif_bmc->client->dev, >> + "Error: Unexpected SMBus command received 0x%x\n", >> + ssif_bmc->smbus_cmd); >> + break; >> + } >> + len = (ssif_bmc->block_num == 0xFF) ? >> + ssif_bmc->remain_len + 1 : MAX_PAYLOAD_PER_TRANSACTION; >> + if (ssif_bmc->msg_idx == (len + 1)) { >> + pec = i2c_smbus_pec(pec, &len, 1); >> + *val = i2c_smbus_pec(pec, ssif_bmc->response_buf, len); >> + } >> + /* Invalidate response buffer to denote last response is sent */ >> + if (ssif_bmc->block_num == 0xFF && >> + ssif_bmc->msg_idx > (ssif_bmc->remain_len + pec_len)) { >> + complete_response(ssif_bmc); >> + } >> + } >> +} >> + >> +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val) >> +{ >> + u8 *buf; >> + u8 smbus_cmd; >> + >> + buf = (u8 *)&ssif_bmc->request; >> + if (ssif_bmc->msg_idx >= sizeof(struct ssif_msg)) > > Shouldn't you abort the message if you get too much data? Otherwise you > get silent truncation. > Will try to abort bad request in next version. >> + return; >> + >> + smbus_cmd = ssif_bmc->smbus_cmd; >> + switch (smbus_cmd) { >> + case SSIF_IPMI_SINGLEPART_WRITE: >> + /* Single-part write */ >> + buf[ssif_bmc->msg_idx - 1] = *val; >> + ssif_bmc->msg_idx++; >> + >> + break; > > Generally you put the space after the break, not before. You did this > right before, but didn't from here down in the file. > Will fix them in next version. >> + case SSIF_IPMI_MULTIPART_WRITE_START: >> + /* Reset length to zero */ >> + if (ssif_bmc->msg_idx == 1) >> + ssif_bmc->request.len = 0; > > What happens if you get this and you are in the middle of a message? > As per specs, this message should be discarded. This part is still missing. I'll try to add this feature in next version. >> + >> + fallthrough; >> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE: >> + case SSIF_IPMI_MULTIPART_WRITE_END: > > What happens if you get these and you are not in a message? > Same as my comment above. >> + /* Multi-part write, 2nd byte received is length */ >> + if (ssif_bmc->msg_idx == 1) { >> + ssif_bmc->request.len += *val; >> + ssif_bmc->recv_len = *val; >> + } else { >> + buf[ssif_bmc->msg_idx - 1 + >> + ssif_bmc->request.len - ssif_bmc->recv_len] = *val; >> + } >> + >> + ssif_bmc->msg_idx++; >> + >> + break; >> + default: >> + /* Do not expect to go to this case */ >> + dev_err(&ssif_bmc->client->dev, >> + "Error: Unexpected SMBus command received 0x%x\n", ssif_bmc->smbus_cmd); >> + break; >> + } >> +} >> + >> +static bool validate_pec(struct ssif_bmc_ctx *ssif_bmc) >> +{ >> + u8 rpec = 0, cpec = 0; >> + bool ret = true; >> + u8 addr, index; >> + u8 *buf; >> + >> + buf = (u8 *)&ssif_bmc->request; >> + switch (ssif_bmc->smbus_cmd) { >> + case SSIF_IPMI_SINGLEPART_WRITE: >> + if ((ssif_bmc->msg_idx - 1) == ssif_msg_len(&ssif_bmc->request)) { >> + /* PEC is not included */ >> + ssif_bmc->pec_support = false; >> + return true; >> + } >> + >> + if ((ssif_bmc->msg_idx - 1) != (ssif_msg_len(&ssif_bmc->request) + 1)) >> + goto error; >> + >> + /* PEC is included */ >> + ssif_bmc->pec_support = true; >> + rpec = buf[ssif_bmc->msg_idx - 2]; >> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr); >> + cpec = i2c_smbus_pec(cpec, &addr, 1); >> + cpec = i2c_smbus_pec(cpec, &ssif_bmc->smbus_cmd, 1); >> + cpec = i2c_smbus_pec(cpec, buf, ssif_msg_len(&ssif_bmc->request)); >> + if (rpec != cpec) { >> + dev_err(&ssif_bmc->client->dev, "Bad PEC 0x%02x vs. 0x%02x\n", rpec, cpec); >> + ret = false; >> + } >> + >> + break; >> + case SSIF_IPMI_MULTIPART_WRITE_START: >> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE: >> + case SSIF_IPMI_MULTIPART_WRITE_END: >> + index = ssif_bmc->request.len - ssif_bmc->recv_len; >> + if ((ssif_bmc->msg_idx - 1 + index) == ssif_msg_len(&ssif_bmc->request)) { >> + /* PEC is not included */ >> + ssif_bmc->pec_support = false; >> + return true; >> + } >> + >> + if ((ssif_bmc->msg_idx - 1 + index) != (ssif_msg_len(&ssif_bmc->request) + 1)) >> + goto error; >> + >> + /* PEC is included */ >> + ssif_bmc->pec_support = true; >> + rpec = buf[ssif_bmc->msg_idx - 2 + index]; >> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr); >> + cpec = i2c_smbus_pec(cpec, &addr, 1); >> + cpec = i2c_smbus_pec(cpec, &ssif_bmc->smbus_cmd, 1); >> + cpec = i2c_smbus_pec(cpec, &ssif_bmc->recv_len, 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-bytes 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 (ssif_bmc->recv_len != 0) >> + cpec = i2c_smbus_pec(cpec, buf + 1 + index, ssif_bmc->recv_len); >> + >> + if (rpec != cpec) { >> + dev_err(&ssif_bmc->client->dev, "Bad PEC 0x%02x vs. 0x%02x\n", rpec, cpec); >> + ret = false; >> + } >> + >> + break; >> + default: >> + break; >> + } >> + >> + return ret; >> +error: >> + /* Do not expect to go to this case */ >> + dev_err(&ssif_bmc->client->dev, >> + "Error: Unexpected length received %d\n", ssif_msg_len(&ssif_bmc->request)); >> + >> + return false; >> +} >> + >> +static void complete_write_received(struct ssif_bmc_ctx *ssif_bmc) >> +{ >> + u8 cmd = ssif_bmc->smbus_cmd; >> + >> + /* A BMC that receives an invalid PEC shall 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 >> + */ >> + if (!validate_pec(ssif_bmc)) { >> + dev_err(&ssif_bmc->client->dev, "Received invalid PEC\n"); >> + return; >> + } >> + >> + if (cmd == SSIF_IPMI_SINGLEPART_WRITE || cmd == SSIF_IPMI_MULTIPART_WRITE_END) >> + handle_request(ssif_bmc); >> +} >> + >> +static void initialize_transfer(struct ssif_bmc_ctx *ssif_bmc, u8 *val) >> +{ >> + /* SMBUS command can vary (single or multi-part) */ >> + ssif_bmc->smbus_cmd = *val; >> + ssif_bmc->msg_idx++; >> + >> + if (ssif_bmc->smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE || >> + ssif_bmc->smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_START) { >> + /* >> + * The response can be delayed in BMC causing host SSIF driver >> + * to timeout and send a new request once BMC slave is ready. >> + * In that case check for pending response and clear it >> + */ >> + if (ssif_bmc->response_in_progress) { >> + dev_err(&ssif_bmc->client->dev, >> + "Warn: SSIF new request with pending response"); >> + complete_response(ssif_bmc); >> + } >> + } else if (unlikely(ssif_bmc->smbus_cmd != SSIF_IPMI_SINGLEPART_READ && >> + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_WRITE_MIDDLE && >> + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_WRITE_END && >> + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_READ_START && >> + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_READ_MIDDLE)) { >> + /* Unknown command, clear it */ >> + dev_err(&ssif_bmc->client->dev, "Warn: Unknown SMBus command"); >> + complete_response(ssif_bmc); >> + } >> +} >> + >> +/* >> + * 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); >> + >> + spin_lock_irqsave(&ssif_bmc->lock, flags); >> + >> + /* I2C Event Handler: >> + * I2C_SLAVE_READ_REQUESTED 0x0 >> + * I2C_SLAVE_WRITE_REQUESTED 0x1 >> + * I2C_SLAVE_READ_PROCESSED 0x2 >> + * I2C_SLAVE_WRITE_RECEIVED 0x3 >> + * I2C_SLAVE_STOP 0x4 >> + */ >> + switch (event) { >> + case I2C_SLAVE_READ_REQUESTED: >> + ssif_bmc->msg_idx = 0; >> + if (ssif_bmc->is_singlepart_read) >> + *val = ssif_bmc->response.len; >> + else >> + set_multipart_response_buffer(ssif_bmc, val); >> + break; >> + >> + case I2C_SLAVE_WRITE_REQUESTED: >> + ssif_bmc->msg_idx = 0; >> + break; >> + >> + case I2C_SLAVE_READ_PROCESSED: >> + handle_read_processed(ssif_bmc, val); >> + break; >> + >> + case I2C_SLAVE_WRITE_RECEIVED: >> + if (ssif_bmc->msg_idx) >> + handle_write_received(ssif_bmc, val); >> + else >> + initialize_transfer(ssif_bmc, val); >> + >> + break; >> + >> + case I2C_SLAVE_STOP: >> + if (ssif_bmc->last_event == I2C_SLAVE_WRITE_RECEIVED) >> + complete_write_received(ssif_bmc); >> + /* Reset message index */ >> + ssif_bmc->msg_idx = 0; >> + break; >> + >> + default: >> + break; >> + } >> + ssif_bmc->last_event = event; >> + spin_unlock_irqrestore(&ssif_bmc->lock, flags); >> + >> + return 0; >> +} >> + >> +struct ssif_bmc_ctx *ssif_bmc_alloc(struct i2c_client *client, int sizeof_priv) >> +{ >> + struct ssif_bmc_ctx *ssif_bmc; >> + int ret; >> + >> + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc) + sizeof_priv, GFP_KERNEL); >> + if (!ssif_bmc) >> + return ERR_PTR(-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; >> + >> + /* 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 ssif_bmc; >> + >> +out: >> + devm_kfree(&client->dev, ssif_bmc); >> + return ERR_PTR(ret); >> +} >> +EXPORT_SYMBOL(ssif_bmc_alloc); >> + >> +MODULE_AUTHOR("Chuong Tran "); >> +MODULE_AUTHOR("Quan Nguyen "); >> +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface."); >> +MODULE_LICENSE("GPL v2"); >> diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h >> new file mode 100644 >> index 000000000000..eab540061f14 >> --- /dev/null >> +++ b/drivers/char/ipmi/ssif_bmc.h >> @@ -0,0 +1,93 @@ >> +/* SPDX-License-Identifier: GPL-2.0+ */ >> +/* >> + * The driver for BMC side of SSIF interface >> + * >> + * Copyright (c) 2021, Ampere Computing LLC >> + * >> + * This program is free software; you can redistribute it and/or >> + * modify it under the terms of the GNU General Public License as >> + * published by the Free Software Foundation; either version 2 of >> + * the License, or (at your option) any later version. >> + * >> + * 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. >> + * >> + * You should have received a copy of the GNU General Public License >> + * along with this program. If not, see . >> + */ >> +#ifndef __SSIF_BMC_H__ >> +#define __SSIF_BMC_H__ >> + >> +#define DEVICE_NAME "ipmi-ssif-host" >> + >> +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff) >> + >> +#define MSG_PAYLOAD_LEN_MAX 252 >> + >> +/* A standard SMBus Transaction is limited to 32 data bytes */ >> +#define MAX_PAYLOAD_PER_TRANSACTION 32 >> + >> +#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 >> + >> +struct ssif_msg { >> + u8 len; >> + u8 netfn_lun; >> + u8 cmd; >> + u8 payload[MSG_PAYLOAD_LEN_MAX]; >> +} __packed; >> + >> +static inline u32 ssif_msg_len(struct ssif_msg *ssif_msg) >> +{ >> + return ssif_msg->len + 1; >> +} >> + >> +#define SSIF_BMC_BUSY 0x01 >> +#define SSIF_BMC_READY 0x02 >> + >> +struct ssif_bmc_ctx { >> + struct i2c_client *client; >> + struct miscdevice miscdev; >> + u8 running; >> + u8 smbus_cmd; >> + struct ssif_msg request; >> + bool request_available; >> + struct ssif_msg response; >> + bool response_in_progress; >> + /* Response buffer for Multi-part Read Transaction */ >> + u8 response_buf[MAX_PAYLOAD_PER_TRANSACTION]; >> + /* 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; >> + size_t msg_idx; >> + enum i2c_slave_event last_event; >> + bool pec_support; >> + /* spinlock */ >> + spinlock_t lock; >> + wait_queue_head_t wait_queue; >> + void (*set_ssif_bmc_status)(struct ssif_bmc_ctx *ssif_bmc, unsigned int flags); >> + void *priv; >> +}; >> + >> +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file) >> +{ >> + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev); >> +} >> + >> +struct ssif_bmc_ctx *ssif_bmc_alloc(struct i2c_client *client, int sizeof_priv); >> + >> +#endif /* __SSIF_BMC_H__ */ >> -- >> 2.28.0 >>