Re: [PATCH 2/2] soc: qcom: smp2p: Add support for smp2p v2
From: Deepak Kumar Singh
Date: Wed Oct 22 2025 - 06:50:31 EST
On 10/21/2025 3:09 PM, Konrad Dybcio wrote:
On 10/21/25 10:23 AM, Deepak Kumar Singh wrote:Good point, i think that should never happen for early boot processor which will use version 2. That can possibly happen for processor that is coming late than local host(version 1). In that case anyway we are setting default version 1 and proceeding. >>>> /*
On 9/24/2025 8:27 PM, Konrad Dybcio wrote:
On 9/24/25 6:18 AM, Jingyi Wang wrote:I think that should be ok. If we return error smp2p connection will be completely broken. With default version 1 partial features can be supported even if remote is using version 2. Some features like smp2p connection after subsystem restart may be affected by this.>> +}
From: Chris Lew <chris.lew@xxxxxxxxxxxxxxxx>
Some remoteproc need smp2p v2 support, mirror the version written by the
remote if the remote supports v2. This is needed if the remote does not
have backwards compatibility with v1. And reset entry last value on SSR for
smp2p v2.
Signed-off-by: Chris Lew <chris.lew@xxxxxxxxxxxxxxxx>
Co-developed-by: Jingyi Wang <jingyi.wang@xxxxxxxxxxxxxxxx>
Signed-off-by: Jingyi Wang <jingyi.wang@xxxxxxxxxxxxxxxx>
---
[...]
+static int qcom_smp2p_in_version(struct qcom_smp2p *smp2p)
+{
+ unsigned int smem_id = smp2p->smem_items[SMP2P_INBOUND];
+ unsigned int pid = smp2p->remote_pid;
+ struct smp2p_smem_item *in;
+ size_t size;
+
+ in = qcom_smem_get(pid, smem_id, &size);
+ if (IS_ERR(in))
+ return 0;
+
+ return in->version;
are in and out versions supposed to be out of sync in case of
error?
Perhaps a different question is in order.. do we ever expect smem_get to
fail under normal conditions?
[...]
Yes in_version ?:1 is short hand but i find (in_version) ? in_version : 1; more readable and obvious.We want to assign in_version when value is 1/2 and 1 if value is 0 i.e. error case.* Make sure the rest of the header is written before we validate the
* item by writing a valid version number.
*/
wmb();
- out->version = 1;
+ out->version = (in_version) ? in_version : 1;
= in_version ?: 1
Konrad
That's what this syntax does, with less characters
Konrad