FROMLIST: soc: qcom: smp2p: Add support for smp2p v2

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.

Link: https://lore.kernel.org/r/20251103152929.2434911-3-deepak.singh@oss.qualcomm.com
Signed-off-by: Chris Lew <chris.lew@oss.qualcomm.com>
Signed-off-by: Deepak Kumar Singh <deepak.singh@oss.qualcomm.com>

Author: quic-clew

drivers/soc/qcom/smp2p.c

@@ -36,6 +36,10 @@
  * The driver uses the Linux GPIO and interrupt framework to expose a virtual
  * GPIO for each outbound entry and a virtual interrupt controller for each
  * inbound entry.
+ *
+ * Driver supports two versions:
+ * V1 - For processor that start after local host
+ * V2 - For processor that start in early boot sequence
  */
 
 #define SMP2P_MAX_ENTRY 16
@@ -50,11 +54,12 @@
 
 #define ONE 1
 #define TWO 2
+#define MAX_VERSION TWO
 
 /**
  * struct smp2p_smem_item - in memory communication structure
  * @magic:		magic number
- * @version:		version - must be 1
+ * @version:		version
  * @features:		features flag - currently unused
  * @local_pid:		processor id of sending end
  * @remote_pid:		processor id of receiving end
@@ -183,14 +188,23 @@ static void qcom_smp2p_kick(struct qcom_smp2p *smp2p)
 static bool qcom_smp2p_check_ssr(struct qcom_smp2p *smp2p)
 {
 	struct smp2p_smem_item *in = smp2p->in;
+	struct smp2p_entry *entry;
 	bool restart;
 
 	if (!smp2p->ssr_ack_enabled)
 		return false;
 
 	restart = in->flags & BIT(SMP2P_FLAGS_RESTART_DONE_BIT);
+	restart = restart != smp2p->ssr_ack;
+	if (restart && in->version > ONE) {
+		list_for_each_entry(entry, &smp2p->inbound, node) {
+			if (!entry->value)
+				continue;
+			entry->last_value = 0;
+		}
+	}
 
-	return restart != smp2p->ssr_ack;
+	return restart;
 }
 
 static void qcom_smp2p_do_ssr_ack(struct qcom_smp2p *smp2p)
@@ -225,6 +239,20 @@ static void qcom_smp2p_negotiate(struct qcom_smp2p *smp2p)
 	}
 }
 
+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;
+}
+
 static void qcom_smp2p_start_in(struct qcom_smp2p *smp2p)
 {
 	unsigned int smem_id = smp2p->smem_items[SMP2P_INBOUND];
@@ -522,6 +550,7 @@ static int qcom_smp2p_alloc_outbound_item(struct qcom_smp2p *smp2p)
 	struct smp2p_smem_item *out;
 	unsigned smem_id = smp2p->smem_items[SMP2P_OUTBOUND];
 	unsigned pid = smp2p->remote_pid;
+	u8 in_version;
 	int ret;
 
 	ret = qcom_smem_alloc(pid, smem_id, sizeof(*out));
@@ -543,12 +572,18 @@ static int qcom_smp2p_alloc_outbound_item(struct qcom_smp2p *smp2p)
 	out->valid_entries = 0;
 	out->features = SMP2P_ALL_FEATURES;
 
+	in_version = qcom_smp2p_in_version(smp2p);
+	if (in_version > MAX_VERSION) {
+		dev_err(smp2p->dev, "Unsupported smp2p version\n");
+		return -EINVAL;
+	}
+
 	/*
 	 * 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;
 
 	qcom_smp2p_kick(smp2p);