[PATCH 1/4] remoteproc: k3-r5: Fix IPC-only mode detection

Richard Genoud
2024-06-21T15:01:09Z

ret variable was used to test reset status, get from
reset_control_status() call. But this variable was overwritten by
ti_sci_proc_get_status() a few lines bellow.
And as ti_sci_proc_get_status() returns 0 or a negative value (in this
latter case, followed by a return), the expression !ret was always true,

Clearly, this was not what was intended:
In the comment above it's said that "requires both local and module
resets to be deasserted"; if reset_control_status() returns 0 it means
that the reset line is deasserted.
So, it's pretty clear that the return value of reset_control_status()
was intended to be used instead of ti_sci_proc_get_status() return
value.

This could lead in an incorrect IPC-only mode detection if reset line is
asserted (so reset_control_status() return > 0) and c_state != 0 and
halted == 0.
In this case, the old code would have detected an IPC-only mode instead
of a mismatched mode.

Fixes: 1168af40b1ad ("remoteproc: k3-r5: Add support for IPC-only mode for all R5Fs")
Signed-off-by: Richard Genoud <richard.genoud@bootlin.com>
---
drivers/remoteproc/ti_k3_r5_remoteproc.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
index 50e486bcfa10..39a47540c590 100644
--- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
+++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
@@ -1144,6 +1144,7 @@ static int k3_r5_rproc_configure_mode(struct k3_r5_rproc *kproc)
u32 atcm_enable, btcm_enable, loczrama;
struct k3_r5_core *core0;
enum cluster_mode mode = cluster->mode;
+ int reset_ctrl_status;
int ret;

core0 = list_first_entry(&cluster->cores, struct k3_r5_core, elem);
@@ -1160,11 +1161,11 @@ static int k3_r5_rproc_configure_mode(struct k3_r5_rproc *kproc)
r_state, c_state);
}

- ret = reset_control_status(core->reset);
- if (ret < 0) {
+ reset_ctrl_status = reset_control_status(core->reset);
+ if (reset_ctrl_status < 0) {
dev_err(cdev, "failed to get initial local reset status, ret = %d\n",
- ret);
- return ret;
+ reset_ctrl_status);
+ return reset_ctrl_status;
}

/*
@@ -1199,7 +1200,7 @@ static int k3_r5_rproc_configure_mode(struct k3_r5_rproc *kproc)
* irrelevant if module reset is asserted (POR value has local reset
* deasserted), and is deemed as remoteproc mode
*/
- if (c_state && !ret && !halted) {
+ if (c_state && !reset_ctrl_status && !halted) {
dev_info(cdev, "configured R5F for IPC-only mode\n");
kproc->rproc->state = RPROC_DETACHED;
ret = 1;
@@ -1217,7 +1218,7 @@ static int k3_r5_rproc_configure_mode(struct k3_r5_rproc *kproc)
ret = 0;
} else {
dev_err(cdev, "mismatched mode: local_reset = %s, module_reset = %s, core_state = %s\n",
- !ret ? "deasserted" : "asserted",
+ !reset_ctrl_status ? "deasserted" : "asserted",
c_state ? "deasserted" : "asserted",
halted ? "halted" : "unhalted");
ret = -EINVAL;