add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/drivers/firmware/arm_scmi/smc.c
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@@ -9,9 +9,11 @@
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 #include <linux/arm-smccc.h>
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 #include <linux/device.h>
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 #include <linux/err.h>
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+#include <linux/interrupt.h>
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 #include <linux/mutex.h>
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 #include <linux/of.h>
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 #include <linux/of_address.h>
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+#include <linux/of_irq.h>
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 #include <linux/slab.h>
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 #include "common.h"
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@@ -23,6 +25,8 @@
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  * @shmem: Transmit/Receive shared memory area
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  * @shmem_lock: Lock to protect access to Tx/Rx shared memory area
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  * @func_id: smc/hvc call function id
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+ * @irq: Optional; employed when platforms indicates msg completion by intr.
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+ * @tx_complete: Optional, employed only when irq is valid.
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  */
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 struct scmi_smc {
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@@ -30,7 +34,18 @@
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 	struct scmi_shared_mem __iomem *shmem;
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 	struct mutex shmem_lock;
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 	u32 func_id;
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+	int irq;
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+	struct completion tx_complete;
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 };
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+
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+static irqreturn_t smc_msg_done_isr(int irq, void *data)
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+{
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+	struct scmi_smc *scmi_info = data;
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+
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+	complete(&scmi_info->tx_complete);
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+
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+	return IRQ_HANDLED;
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+}
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 static bool smc_chan_available(struct device *dev, int idx)
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 {
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@@ -51,7 +66,7 @@
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 	struct resource res;
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 	struct device_node *np;
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 	u32 func_id;
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-	int ret;
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+	int ret, irq;
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 	if (!tx)
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 		return -ENODEV;
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@@ -78,6 +93,24 @@
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 	ret = of_property_read_u32(dev->of_node, "arm,smc-id", &func_id);
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 	if (ret < 0)
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 		return ret;
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+
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+	/*
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+	 * If there is an interrupt named "a2p", then the service and
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+	 * completion of a message is signaled by an interrupt rather than by
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+	 * the return of the SMC call.
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+	 */
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+	irq = of_irq_get_byname(cdev->of_node, "a2p");
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+	if (irq > 0) {
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+		ret = devm_request_irq(dev, irq, smc_msg_done_isr,
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+				       IRQF_NO_SUSPEND,
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+				       dev_name(dev), scmi_info);
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+		if (ret) {
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+			dev_err(dev, "failed to setup SCMI smc irq\n");
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+			return ret;
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+		}
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+		init_completion(&scmi_info->tx_complete);
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+		scmi_info->irq = irq;
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+	}
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 	scmi_info->func_id = func_id;
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 	scmi_info->cinfo = cinfo;
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@@ -110,7 +143,14 @@
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 	shmem_tx_prepare(scmi_info->shmem, xfer);
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+	if (scmi_info->irq)
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+		reinit_completion(&scmi_info->tx_complete);
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+
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 	arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
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+
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+	if (scmi_info->irq)
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+		wait_for_completion(&scmi_info->tx_complete);
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+
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 	scmi_rx_callback(scmi_info->cinfo, shmem_read_header(scmi_info->shmem));
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 	mutex_unlock(&scmi_info->shmem_lock);
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@@ -137,7 +177,7 @@
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 	return shmem_poll_done(scmi_info->shmem, xfer);
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 }
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-static struct scmi_transport_ops scmi_smc_ops = {
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+static const struct scmi_transport_ops scmi_smc_ops = {
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 	.chan_available = smc_chan_available,
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 	.chan_setup = smc_chan_setup,
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 	.chan_free = smc_chan_free,