Re: [PATCH 3/4] remoteproc: k3-r5: k3_r5_rproc_stop: code reorder

Richard GENOUD
2024-07-01T08:03:38Z

Le 28/06/2024 à 23:18, Mathieu Poirier a écrit :
> On Fri, Jun 21, 2024 at 05:00:57PM +0200, Richard Genoud wrote:
>> In the next commit, a RP_MBOX_SHUTDOWN message will be sent in
>> k3_r5_rproc_stop() to the remote proc (in lockstep on not)
>> Thus, the sanity check "do not allow core 0 to stop before core 1"
>> should be moved at the beginning of the function so that the generic case
>> can be dealt with.
>>
>> In order to have an easier patch to review, those actions are broke in
>> two patches:
>> - this patch: moving the sanity check at the beginning (No functional
>> change).
>> - next patch: doing the real job (sending shutdown messages to remote
>> procs before halting them).
>>
>> Basically, we had:
>> - cluster_mode actions
>> - !cluster_mode sanity check
>> - !cluster_mode actions
>> And now:
>> - !cluster_mode sanity check
>> - cluster_mode actions
>> - !cluster_mode actions
>>
>> Signed-off-by: Richard Genoud <richard.genoud@bootlin.com>
>> ---
>> drivers/remoteproc/ti_k3_r5_remoteproc.c | 24 ++++++++++++++----------
>> 1 file changed, 14 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> index 1f18b08618c8..a2ead87952c7 100644
>> --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> @@ -636,16 +636,8 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
>> struct k3_r5_core *core1, *core = kproc->core;
>> int ret;
>>
>> - /* halt all applicable cores */
>> - if (cluster->mode == CLUSTER_MODE_LOCKSTEP) {
>> - list_for_each_entry(core, &cluster->cores, elem) {
>> - ret = k3_r5_core_halt(core);
>> - if (ret) {
>> - core = list_prev_entry(core, elem);
>> - goto unroll_core_halt;
>> - }
>> - }
>> - } else {
>> +
>> + if (cluster->mode != CLUSTER_MODE_LOCKSTEP) {
>> /* do not allow core 0 to stop before core 1 */
>> core1 = list_last_entry(&cluster->cores, struct k3_r5_core,
>> elem);
>> @@ -656,6 +648,18 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
>> ret = -EPERM;
>> goto out;
>> }
>> + }
>> +
>> + /* halt all applicable cores */
>> + if (cluster->mode == CLUSTER_MODE_LOCKSTEP) {
>> + list_for_each_entry(core, &cluster->cores, elem) {
>> + ret = k3_r5_core_halt(core);
>> + if (ret) {
>> + core = list_prev_entry(core, elem);
>> + goto unroll_core_halt;
>> + }
>> + }
>> + } else {
>>
>> ret = k3_r5_core_halt(core);
>> if (ret)
>
> With this patch, the "else" in this "if" condition is coupled with the "if" from
> the lockstep mode, making the code extremaly hard to read. The original code
> has a k3_r5_core_halt() in both "if" conditions, making the condition
> independent from one another.
>
I'm not sure I understand what you mean.
Anyway, I'm not happy with this diff, it doesn't reflect what was intended.
(which is moving the check "core 0 should not be stop before core 1" at the beginning)

Tweaking around with the diff algorithms, I came with something way easier to read I think:

diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
index 1f18b08618c8..a2ead87952c7 100644
--- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
+++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
@@ -636,6 +636,20 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
struct k3_r5_core *core1, *core = kproc->core;
int ret;

+
+ if (cluster->mode != CLUSTER_MODE_LOCKSTEP) {
+ /* do not allow core 0 to stop before core 1 */
+ core1 = list_last_entry(&cluster->cores, struct k3_r5_core,
+ elem);
+ if (core != core1 && core1->rproc->state != RPROC_OFFLINE &&
+ core1->rproc->state != RPROC_SUSPENDED) {
+ dev_err(dev, "%s: can not stop core 0 before core 1\n",
+ __func__);
+ ret = -EPERM;
+ goto out;
+ }
+ }
+
/* halt all applicable cores */
if (cluster->mode == CLUSTER_MODE_LOCKSTEP) {
list_for_each_entry(core, &cluster->cores, elem) {
@@ -646,16 +660,6 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
}
}
} else {
- /* do not allow core 0 to stop before core 1 */
- core1 = list_last_entry(&cluster->cores, struct k3_r5_core,
- elem);
- if (core != core1 && core1->rproc->state != RPROC_OFFLINE &&
- core1->rproc->state != RPROC_SUSPENDED) {
- dev_err(dev, "%s: can not stop core 0 before core 1\n",
- __func__);
- ret = -EPERM;
- goto out;
- }

ret = k3_r5_core_halt(core);
if (ret)