Re: [PATCH v2 03/16] soc: qcom: apr: Add GPR support

Many thanks Pierre for the review,

On 14/07/2021 17:20, Pierre-Louis Bossart wrote:

quoted

+void gpr_free_port(gpr_port_t *port)
+{
+	struct packet_router *gpr = port->pr;
+	unsigned long flags;
+
+	spin_lock_irqsave(&gpr->svcs_lock, flags);
+	idr_remove(&gpr->svcs_idr, port->id);
+	spin_unlock_irqrestore(&gpr->svcs_lock, flags);

maybe add a comment somewhere on why you need the irqsave/irqrestore version of spin_lock/unlock?

All the responses to the messages arrive in interrupt context which 
could try to find the matching svc idr, so we needed this irq version of 
spinlock here. I did move this handling to a work queue in the past, so 
we should be able to relax this lock to non-irq version.

It's not very clear by looking at this patch only that those locks are handled in interrupt context.

quoted

+
+	kfree(port);
+}
+EXPORT_SYMBOL_GPL(gpr_free_port);
+
+gpr_port_t *gpr_alloc_port(struct apr_device *gdev, struct device *dev,
+				gpr_port_cb cb,	void *priv)
+{
+	struct packet_router *pr = dev_get_drvdata(gdev->dev.parent);
+	gpr_port_t *port;
+	struct pkt_router_svc *svc;
+	int id;
+
+	port = kzalloc(sizeof(*port), GFP_KERNEL);
+	if (!port)
+		return ERR_PTR(-ENOMEM);
+
+	svc = port;
+	svc->callback = cb;
+	svc->pr = pr;
+	svc->priv = priv;
+	svc->dev = dev;
+	spin_lock_init(&svc->lock);
+
+	spin_lock(&pr->svcs_lock);
+	id = idr_alloc_cyclic(&pr->svcs_idr, svc, GPR_DYNAMIC_PORT_START,
+			      GPR_DYNAMIC_PORT_END, GFP_ATOMIC);
+	if (id < 0) {
+		dev_err(dev, "Unable to allocate dynamic GPR src port\n");
+		kfree(port);
+		spin_unlock(&pr->svcs_lock);

nit-pick: more this before the dev_err?

I agree, will do that in next spin.

quoted

+		return ERR_PTR(-ENOMEM);
+	}
+
+	svc->id = id;
+	spin_unlock(&pr->svcs_lock);
+
+	dev_info(dev, "Adding GPR src port (%x)\n", svc->id);
+
+	return port;
+}

quoted

+static int gpr_do_rx_callback(struct packet_router *gpr, struct apr_rx_buf *abuf)
+{
+	uint16_t hdr_size, ver;
+	struct pkt_router_svc *svc = NULL;

unnecessary init? it's overritten...

Yep.


--srini

quoted

+	struct gpr_resp_pkt resp;
+	struct gpr_hdr *hdr;
+	unsigned long flags;
+	void *buf = abuf->buf;
+	int len = abuf->len;
+
+	hdr = buf;
+	ver = hdr->version;
+	if (ver > GPR_PKT_VER + 1)
+		return -EINVAL;
+
+	hdr_size = hdr->hdr_size;
+	if (hdr_size < GPR_PKT_HEADER_WORD_SIZE) {
+		dev_err(gpr->dev, "GPR: Wrong hdr size:%d\n", hdr_size);
+		return -EINVAL;
+	}
+
+	if (hdr->pkt_size < GPR_PKT_HEADER_BYTE_SIZE || hdr->pkt_size != len) {
+		dev_err(gpr->dev, "GPR: Wrong packet size\n");
+		return -EINVAL;
+	}
+
+	resp.hdr = *hdr;
+	resp.payload_size = hdr->pkt_size - (hdr_size * 4);
+
+	/*
+	 * NOTE: hdr_size is not same as GPR_HDR_SIZE as remote can include
+	 * optional headers in to gpr_hdr which should be ignored
+	 */
+	if (resp.payload_size > 0)
+		resp.payload = buf + (hdr_size *  4);
+
+
+	spin_lock_irqsave(&gpr->svcs_lock, flags);
+	svc = idr_find(&gpr->svcs_idr, hdr->dest_port);

... here

quoted

+	spin_unlock_irqrestore(&gpr->svcs_lock, flags);
+
+	if (!svc) {
+		dev_err(gpr->dev, "GPR: Port(%x) is not registered\n",
+			hdr->dest_port);
+		return -EINVAL;
+	}
+
+	if (svc->callback)
+		svc->callback(&resp, svc->priv, 0);
+
+	return 0;
+}
+