firmware: arm_scmi: Introduce setup_shmem_iomap

To get the address of shmem could be generalized by introducing
setup_shmem_iomap. Then the duplicated code in mailbox.c, optee.c
and smc.c could be dropped.
Signed-off-by: Peng Fan <peng.fan@nxp.com>
[ Cristian: use OF __free and make use of the new helper also in smc.c ]
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Tested-by: Peng Fan <peng.fan@nxp.com>  #i.MX95 19x19 EVK
Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
Message-Id: <20240812173340.3912830-3-cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/common.h

@@ -351,6 +351,8 @@ bool shmem_poll_done(struct scmi_shared_mem __iomem *shmem,
 		     struct scmi_xfer *xfer);
 bool shmem_channel_free(struct scmi_shared_mem __iomem *shmem);
 bool shmem_channel_intr_enabled(struct scmi_shared_mem __iomem *shmem);
+void __iomem *setup_shmem_iomap(struct scmi_chan_info *cinfo, struct device *dev,
+				bool tx, struct resource *res);
 
 /* declarations for message passing transports */
 struct scmi_msg_payld;

drivers/firmware/arm_scmi/mailbox.c

@@ -178,11 +178,8 @@ static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 	const char *desc = tx ? "Tx" : "Rx";
 	struct device *cdev = cinfo->dev;
 	struct scmi_mailbox *smbox;
-	struct device_node *shmem;
-	int ret, a2p_rx_chan, p2a_chan, p2a_rx_chan, idx = tx ? 0 : 1;
+	int ret, a2p_rx_chan, p2a_chan, p2a_rx_chan;
 	struct mbox_client *cl;
-	resource_size_t size;
-	struct resource res;
 
 	ret = mailbox_chan_validate(cdev, &a2p_rx_chan, &p2a_chan, &p2a_rx_chan);
 	if (ret)
@@ -195,25 +192,9 @@ static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 	if (!smbox)
 		return -ENOMEM;
 
-	shmem = of_parse_phandle(cdev->of_node, "shmem", idx);
-	if (!of_device_is_compatible(shmem, "arm,scmi-shmem")) {
-		of_node_put(shmem);
-		return -ENXIO;
-	}
-
-	ret = of_address_to_resource(shmem, 0, &res);
-	of_node_put(shmem);
-	if (ret) {
-		dev_err(cdev, "failed to get SCMI %s shared memory\n", desc);
-		return ret;
-	}
-
-	size = resource_size(&res);
-	smbox->shmem = devm_ioremap(dev, res.start, size);
-	if (!smbox->shmem) {
-		dev_err(dev, "failed to ioremap SCMI %s shared memory\n", desc);
-		return -EADDRNOTAVAIL;
-	}
+	smbox->shmem = setup_shmem_iomap(cinfo, dev, tx, NULL);
+	if (IS_ERR(smbox->shmem))
+		return PTR_ERR(smbox->shmem);
 
 	cl = &smbox->cl;
 	cl->dev = cdev;

drivers/firmware/arm_scmi/optee.c

@@ -368,38 +368,11 @@ static int setup_dynamic_shmem(struct device *dev, struct scmi_optee_channel *ch
 static int setup_static_shmem(struct device *dev, struct scmi_chan_info *cinfo,
 			      struct scmi_optee_channel *channel)
 {
-	struct device_node *np;
-	resource_size_t size;
-	struct resource res;
-	int ret;
-
-	np = of_parse_phandle(cinfo->dev->of_node, "shmem", 0);
-	if (!of_device_is_compatible(np, "arm,scmi-shmem")) {
-		ret = -ENXIO;
-		goto out;
-	}
-
-	ret = of_address_to_resource(np, 0, &res);
-	if (ret) {
-		dev_err(dev, "Failed to get SCMI Tx shared memory\n");
-		goto out;
-	}
-
-	size = resource_size(&res);
+	channel->req.shmem = setup_shmem_iomap(cinfo, dev, true, NULL);
+	if (IS_ERR(channel->req.shmem))
+		return PTR_ERR(channel->req.shmem);
 
-	channel->req.shmem = devm_ioremap(dev, res.start, size);
-	if (!channel->req.shmem) {
-		dev_err(dev, "Failed to ioremap SCMI Tx shared memory\n");
-		ret = -EADDRNOTAVAIL;
-		goto out;
-	}
-
-	ret = 0;
-
-out:
-	of_node_put(np);
-
-	return ret;
+	return 0;
 }
 
 static int setup_shmem(struct device *dev, struct scmi_chan_info *cinfo,

drivers/firmware/arm_scmi/shmem.c

@@ -7,6 +7,8 @@
 
 #include <linux/ktime.h>
 #include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/processor.h>
 #include <linux/types.h>
 
@@ -133,3 +135,42 @@ bool shmem_channel_intr_enabled(struct scmi_shared_mem __iomem *shmem)
 {
 	return ioread32(&shmem->flags) & SCMI_SHMEM_FLAG_INTR_ENABLED;
 }
+
+void __iomem *setup_shmem_iomap(struct scmi_chan_info *cinfo,
+				struct device *dev, bool tx,
+				struct resource *res)
+{
+	struct device_node *shmem __free(device_node);
+	const char *desc = tx ? "Tx" : "Rx";
+	int ret, idx = tx ? 0 : 1;
+	struct device *cdev = cinfo->dev;
+	struct resource lres = {};
+	resource_size_t size;
+	void __iomem *addr;
+
+	shmem = of_parse_phandle(cdev->of_node, "shmem", idx);
+	if (!shmem)
+		return IOMEM_ERR_PTR(-ENODEV);
+
+	if (!of_device_is_compatible(shmem, "arm,scmi-shmem"))
+		return IOMEM_ERR_PTR(-ENXIO);
+
+	/* Use a local on-stack as a working area when not provided */
+	if (!res)
+		res = &lres;
+
+	ret = of_address_to_resource(shmem, 0, res);
+	if (ret) {
+		dev_err(cdev, "failed to get SCMI %s shared memory\n", desc);
+		return IOMEM_ERR_PTR(ret);
+	}
+
+	size = resource_size(res);
+	addr = devm_ioremap(dev, res->start, size);
+	if (!addr) {
+		dev_err(dev, "failed to ioremap SCMI %s shared memory\n", desc);
+		return IOMEM_ERR_PTR(-EADDRNOTAVAIL);
+	}
+
+	return addr;
+}

drivers/firmware/arm_scmi/smc.c

@@ -130,9 +130,7 @@ static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 	struct device *cdev = cinfo->dev;
 	unsigned long cap_id = ULONG_MAX;
 	struct scmi_smc *scmi_info;
-	resource_size_t size;
-	struct resource res;
-	struct device_node *np;
+	struct resource res = {};
 	u32 func_id;
 	int ret;
 
@@ -143,31 +141,16 @@ static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 	if (!scmi_info)
 		return -ENOMEM;
 
-	np = of_parse_phandle(cdev->of_node, "shmem", 0);
-	if (!of_device_is_compatible(np, "arm,scmi-shmem")) {
-		of_node_put(np);
-		return -ENXIO;
-	}
-
-	ret = of_address_to_resource(np, 0, &res);
-	of_node_put(np);
-	if (ret) {
-		dev_err(cdev, "failed to get SCMI Tx shared memory\n");
-		return ret;
-	}
-
-	size = resource_size(&res);
-	scmi_info->shmem = devm_ioremap(dev, res.start, size);
-	if (!scmi_info->shmem) {
-		dev_err(dev, "failed to ioremap SCMI Tx shared memory\n");
-		return -EADDRNOTAVAIL;
-	}
+	scmi_info->shmem = setup_shmem_iomap(cinfo, dev, tx, &res);
+	if (IS_ERR(scmi_info->shmem))
+		return PTR_ERR(scmi_info->shmem);
 
 	ret = of_property_read_u32(dev->of_node, "arm,smc-id", &func_id);
 	if (ret < 0)
 		return ret;
 
 	if (of_device_is_compatible(dev->of_node, "qcom,scmi-smc")) {
+		resource_size_t size = resource_size(&res);
 		void __iomem *ptr = (void __iomem *)scmi_info->shmem + size - 8;
 		/* The capability-id is kept in last 8 bytes of shmem.
 		 *     +-------+ <-- 0