From 09361ed979e68622977751f6274f280d7aec5cb6 Mon Sep 17 00:00:00 2001 From: Adrian Ng Ho Yin Date: Wed, 8 Jul 2026 00:17:40 -0700 Subject: [PATCH] i3c: master: Validate GET CCC payload length and retry Direct GET once Add retries to struct i3c_ccc_cmd. Validate GET payload length in i3c_master_send_ccc_cmd_locked() after a successful transfer. Retry failed Direct GET CCCs up to cmd->retries times when the driver reports failure or an I3C error; validation failures are not retried. SET CCCs are not retried by default. Signed-off-by: Adrian Ng Ho Yin Signed-off-by: Tze Yee Ng Reviewed-by: Alexandre Mergnat Reviewed-by: Frank Li Tested-by: Tommaso Merciai Tested-by: Claudiu Beznea # on RZ/G3S Link: https://patch.msgid.link/b467f01edfaaa0710f30e719ce7f2753b06c1a3f.1783493868.git.tze.yee.ng@altera.com Signed-off-by: Alexandre Belloni --- drivers/i3c/master.c | 59 ++++++++++++++++++++++++++++++++++++++--- include/linux/i3c/ccc.h | 5 ++++ 2 files changed, 60 insertions(+), 4 deletions(-) diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c index 84cda266d8e3..9c32fd0c5fef 100644 --- a/drivers/i3c/master.c +++ b/drivers/i3c/master.c @@ -966,17 +966,46 @@ static void i3c_ccc_cmd_dest_cleanup(struct i3c_ccc_cmd_dest *dest) kfree(dest->payload.data); } -static void i3c_ccc_cmd_init(struct i3c_ccc_cmd *cmd, bool rnw, u8 id, - struct i3c_ccc_cmd_dest *dests, - unsigned int ndests) +static void i3c_ccc_cmd_init_retries(struct i3c_ccc_cmd *cmd, bool rnw, u8 id, + struct i3c_ccc_cmd_dest *dests, + unsigned int ndests, unsigned int retries) { cmd->rnw = rnw ? 1 : 0; cmd->id = id; cmd->dests = dests; cmd->ndests = ndests; + cmd->retries = retries; cmd->err = I3C_ERROR_UNKNOWN; } +static void i3c_ccc_cmd_init(struct i3c_ccc_cmd *cmd, bool rnw, u8 id, + struct i3c_ccc_cmd_dest *dests, + unsigned int ndests) +{ + i3c_ccc_cmd_init_retries(cmd, rnw, id, dests, ndests, + rnw ? I3C_CCC_RETRIES : 0); +} + +static int i3c_ccc_validate_payload_len(struct i3c_ccc_cmd *cmd) +{ + unsigned int i; + + if (!cmd->rnw) + return 0; + + for (i = 0; i < cmd->ndests; i++) { + struct i3c_ccc_cmd_payload *p = &cmd->dests[i].payload; + + if (p->actual_len > p->len) + return -EIO; + + if (p->len && p->actual_len != p->len) + return -EIO; + } + + return 0; +} + /** * i3c_master_send_ccc_cmd_locked() - send a CCC (Common Command Codes) * @master: master used to send frames on the bus @@ -988,6 +1017,9 @@ static void i3c_ccc_cmd_init(struct i3c_ccc_cmd *cmd, bool rnw, u8 id, static int i3c_master_send_ccc_cmd_locked(struct i3c_master_controller *master, struct i3c_ccc_cmd *cmd) { + unsigned int attempt, max_attempts; + int ret; + if (!cmd || !master) return -EINVAL; @@ -1005,7 +1037,25 @@ static int i3c_master_send_ccc_cmd_locked(struct i3c_master_controller *master, !master->ops->supports_ccc_cmd(master, cmd)) return -EOPNOTSUPP; - return master->ops->send_ccc_cmd(master, cmd); + max_attempts = cmd->retries + 1; + ret = -EIO; + for (attempt = 0; attempt < max_attempts; attempt++) { + unsigned int i; + + if (cmd->rnw) + for (i = 0; i < cmd->ndests; i++) + cmd->dests[i].payload.actual_len = 0; + + cmd->err = I3C_ERROR_UNKNOWN; + ret = master->ops->send_ccc_cmd(master, cmd); + if (!ret && cmd->err == I3C_ERROR_UNKNOWN) + break; + } + + if (!ret) + ret = i3c_ccc_validate_payload_len(cmd); + + return ret; } static struct i2c_dev_desc * @@ -1444,6 +1494,7 @@ static int i3c_master_getmxds_locked(struct i3c_master_controller *master, * while expecting shorter length from this CCC command. */ dest.payload.len -= 3; + i3c_ccc_cmd_init(&cmd, true, I3C_CCC_GETMXDS, &dest, 1); ret = i3c_master_send_ccc_cmd_locked(master, &cmd); if (ret) goto out; diff --git a/include/linux/i3c/ccc.h b/include/linux/i3c/ccc.h index d8052949e57e..2506d83b8255 100644 --- a/include/linux/i3c/ccc.h +++ b/include/linux/i3c/ccc.h @@ -12,6 +12,8 @@ #include /* I3C CCC (Common Command Codes) related definitions */ +#define I3C_CCC_RETRIES 1 + #define I3C_CCC_DIRECT BIT(7) #define I3C_CCC_ID(id, broadcast) \ @@ -374,12 +376,15 @@ struct i3c_ccc_cmd_dest { * @ndests: number of destinations. Should always be one for broadcast commands * @dests: array of destinations and associated payload for this CCC. Most of * the time, only one destination is provided + * @retries: number of times to retry a failed Direct GET CCC (see + * &I3C_CCC_RETRIES) * @err: I3C error code */ struct i3c_ccc_cmd { u8 rnw; u8 id; unsigned int ndests; + unsigned int retries; struct i3c_ccc_cmd_dest *dests; enum i3c_error_code err; };