1 files changed, 361 insertions, 0 deletions
diff --git a/drivers/firmware/imx/imx-scu.c b/drivers/firmware/imx/imx-scu.c
new file mode 100644
index 000000000..dca79cacc
--- /dev/null
+++ b/drivers/firmware/imx/imx-scu.c
@@ -0,0 +1,361 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2018 NXP
+ *  Author: Dong Aisheng <aisheng.dong@nxp.com>
+ *
+ * Implementation of the SCU IPC functions using MUs (client side).
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/firmware/imx/ipc.h>
+#include <linux/firmware/imx/sci.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+#define SCU_MU_CHAN_NUM		8
+#define MAX_RX_TIMEOUT		(msecs_to_jiffies(30))
+
+struct imx_sc_chan {
+	struct imx_sc_ipc *sc_ipc;
+
+	struct mbox_client cl;
+	struct mbox_chan *ch;
+	int idx;
+	struct completion tx_done;
+};
+
+struct imx_sc_ipc {
+	/* SCU uses 4 Tx and 4 Rx channels */
+	struct imx_sc_chan chans[SCU_MU_CHAN_NUM];
+	struct device *dev;
+	struct mutex lock;
+	struct completion done;
+	bool fast_ipc;
+
+	/* temporarily store the SCU msg */
+	u32 *msg;
+	u8 rx_size;
+	u8 count;
+};
+
+/*
+ * This type is used to indicate error response for most functions.
+ */
+enum imx_sc_error_codes {
+	IMX_SC_ERR_NONE = 0,	/* Success */
+	IMX_SC_ERR_VERSION = 1,	/* Incompatible API version */
+	IMX_SC_ERR_CONFIG = 2,	/* Configuration error */
+	IMX_SC_ERR_PARM = 3,	/* Bad parameter */
+	IMX_SC_ERR_NOACCESS = 4,	/* Permission error (no access) */
+	IMX_SC_ERR_LOCKED = 5,	/* Permission error (locked) */
+	IMX_SC_ERR_UNAVAILABLE = 6,	/* Unavailable (out of resources) */
+	IMX_SC_ERR_NOTFOUND = 7,	/* Not found */
+	IMX_SC_ERR_NOPOWER = 8,	/* No power */
+	IMX_SC_ERR_IPC = 9,		/* Generic IPC error */
+	IMX_SC_ERR_BUSY = 10,	/* Resource is currently busy/active */
+	IMX_SC_ERR_FAIL = 11,	/* General I/O failure */
+	IMX_SC_ERR_LAST
+};
+
+static int imx_sc_linux_errmap[IMX_SC_ERR_LAST] = {
+	0,	 /* IMX_SC_ERR_NONE */
+	-EINVAL, /* IMX_SC_ERR_VERSION */
+	-EINVAL, /* IMX_SC_ERR_CONFIG */
+	-EINVAL, /* IMX_SC_ERR_PARM */
+	-EACCES, /* IMX_SC_ERR_NOACCESS */
+	-EACCES, /* IMX_SC_ERR_LOCKED */
+	-ERANGE, /* IMX_SC_ERR_UNAVAILABLE */
+	-EEXIST, /* IMX_SC_ERR_NOTFOUND */
+	-EPERM,	 /* IMX_SC_ERR_NOPOWER */
+	-EPIPE,	 /* IMX_SC_ERR_IPC */
+	-EBUSY,	 /* IMX_SC_ERR_BUSY */
+	-EIO,	 /* IMX_SC_ERR_FAIL */
+};
+
+static struct imx_sc_ipc *imx_sc_ipc_handle;
+
+static inline int imx_sc_to_linux_errno(int errno)
+{
+	if (errno >= IMX_SC_ERR_NONE && errno < IMX_SC_ERR_LAST)
+		return imx_sc_linux_errmap[errno];
+	return -EIO;
+}
+
+/*
+ * Get the default handle used by SCU
+ */
+int imx_scu_get_handle(struct imx_sc_ipc **ipc)
+{
+	if (!imx_sc_ipc_handle)
+		return -EPROBE_DEFER;
+
+	*ipc = imx_sc_ipc_handle;
+	return 0;
+}
+EXPORT_SYMBOL(imx_scu_get_handle);
+
+/* Callback called when the word of a message is ack-ed, eg read by SCU */
+static void imx_scu_tx_done(struct mbox_client *cl, void *mssg, int r)
+{
+	struct imx_sc_chan *sc_chan = container_of(cl, struct imx_sc_chan, cl);
+
+	complete(&sc_chan->tx_done);
+}
+
+static void imx_scu_rx_callback(struct mbox_client *c, void *msg)
+{
+	struct imx_sc_chan *sc_chan = container_of(c, struct imx_sc_chan, cl);
+	struct imx_sc_ipc *sc_ipc = sc_chan->sc_ipc;
+	struct imx_sc_rpc_msg *hdr;
+	u32 *data = msg;
+	int i;
+
+	if (!sc_ipc->msg) {
+		dev_warn(sc_ipc->dev, "unexpected rx idx %d 0x%08x, ignore!\n",
+				sc_chan->idx, *data);
+		return;
+	}
+
+	if (sc_ipc->fast_ipc) {
+		hdr = msg;
+		sc_ipc->rx_size = hdr->size;
+		sc_ipc->msg[0] = *data++;
+
+		for (i = 1; i < sc_ipc->rx_size; i++)
+			sc_ipc->msg[i] = *data++;
+
+		complete(&sc_ipc->done);
+
+		return;
+	}
+
+	if (sc_chan->idx == 0) {
+		hdr = msg;
+		sc_ipc->rx_size = hdr->size;
+		dev_dbg(sc_ipc->dev, "msg rx size %u\n", sc_ipc->rx_size);
+		if (sc_ipc->rx_size > 4)
+			dev_warn(sc_ipc->dev, "RPC does not support receiving over 4 words: %u\n",
+				 sc_ipc->rx_size);
+	}
+
+	sc_ipc->msg[sc_chan->idx] = *data;
+	sc_ipc->count++;
+
+	dev_dbg(sc_ipc->dev, "mu %u msg %u 0x%x\n", sc_chan->idx,
+		sc_ipc->count, *data);
+
+	if ((sc_ipc->rx_size != 0) && (sc_ipc->count == sc_ipc->rx_size))
+		complete(&sc_ipc->done);
+}
+
+static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
+{
+	struct imx_sc_rpc_msg hdr = *(struct imx_sc_rpc_msg *)msg;
+	struct imx_sc_chan *sc_chan;
+	u32 *data = msg;
+	int ret;
+	int size;
+	int i;
+
+	/* Check size */
+	if (hdr.size > IMX_SC_RPC_MAX_MSG)
+		return -EINVAL;
+
+	dev_dbg(sc_ipc->dev, "RPC SVC %u FUNC %u SIZE %u\n", hdr.svc,
+		hdr.func, hdr.size);
+
+	size = sc_ipc->fast_ipc ? 1 : hdr.size;
+	for (i = 0; i < size; i++) {
+		sc_chan = &sc_ipc->chans[i % 4];
+
+		/*
+		 * SCU requires that all messages words are written
+		 * sequentially but linux MU driver implements multiple
+		 * independent channels for each register so ordering between
+		 * different channels must be ensured by SCU API interface.
+		 *
+		 * Wait for tx_done before every send to ensure that no
+		 * queueing happens at the mailbox channel level.
+		 */
+		if (!sc_ipc->fast_ipc) {
+			wait_for_completion(&sc_chan->tx_done);
+			reinit_completion(&sc_chan->tx_done);
+		}
+
+		ret = mbox_send_message(sc_chan->ch, &data[i]);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * RPC command/response
+ */
+int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp)
+{
+	uint8_t saved_svc, saved_func;
+	struct imx_sc_rpc_msg *hdr;
+	int ret;
+
+	if (WARN_ON(!sc_ipc || !msg))
+		return -EINVAL;
+
+	mutex_lock(&sc_ipc->lock);
+	reinit_completion(&sc_ipc->done);
+
+	if (have_resp) {
+		sc_ipc->msg = msg;
+		saved_svc = ((struct imx_sc_rpc_msg *)msg)->svc;
+		saved_func = ((struct imx_sc_rpc_msg *)msg)->func;
+	}
+	sc_ipc->count = 0;
+	ret = imx_scu_ipc_write(sc_ipc, msg);
+	if (ret < 0) {
+		dev_err(sc_ipc->dev, "RPC send msg failed: %d\n", ret);
+		goto out;
+	}
+
+	if (have_resp) {
+		if (!wait_for_completion_timeout(&sc_ipc->done,
+						 MAX_RX_TIMEOUT)) {
+			dev_err(sc_ipc->dev, "RPC send msg timeout\n");
+			mutex_unlock(&sc_ipc->lock);
+			return -ETIMEDOUT;
+		}
+
+		/* response status is stored in hdr->func field */
+		hdr = msg;
+		ret = hdr->func;
+		/*
+		 * Some special SCU firmware APIs do NOT have return value
+		 * in hdr->func, but they do have response data, those special
+		 * APIs are defined as void function in SCU firmware, so they
+		 * should be treated as return success always.
+		 */
+		if ((saved_svc == IMX_SC_RPC_SVC_MISC) &&
+			(saved_func == IMX_SC_MISC_FUNC_UNIQUE_ID ||
+			 saved_func == IMX_SC_MISC_FUNC_GET_BUTTON_STATUS))
+			ret = 0;
+	}
+
+out:
+	sc_ipc->msg = NULL;
+	mutex_unlock(&sc_ipc->lock);
+
+	dev_dbg(sc_ipc->dev, "RPC SVC done\n");
+
+	return imx_sc_to_linux_errno(ret);
+}
+EXPORT_SYMBOL(imx_scu_call_rpc);
+
+static int imx_scu_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct imx_sc_ipc *sc_ipc;
+	struct imx_sc_chan *sc_chan;
+	struct mbox_client *cl;
+	char *chan_name;
+	struct of_phandle_args args;
+	int num_channel;
+	int ret;
+	int i;
+
+	sc_ipc = devm_kzalloc(dev, sizeof(*sc_ipc), GFP_KERNEL);
+	if (!sc_ipc)
+		return -ENOMEM;
+
+	ret = of_parse_phandle_with_args(pdev->dev.of_node, "mboxes",
+					 "#mbox-cells", 0, &args);
+	if (ret)
+		return ret;
+
+	sc_ipc->fast_ipc = of_device_is_compatible(args.np, "fsl,imx8-mu-scu");
+
+	num_channel = sc_ipc->fast_ipc ? 2 : SCU_MU_CHAN_NUM;
+	for (i = 0; i < num_channel; i++) {
+		if (i < num_channel / 2)
+			chan_name = kasprintf(GFP_KERNEL, "tx%d", i);
+		else
+			chan_name = kasprintf(GFP_KERNEL, "rx%d",
+					      i - num_channel / 2);
+
+		if (!chan_name)
+			return -ENOMEM;
+
+		sc_chan = &sc_ipc->chans[i];
+		cl = &sc_chan->cl;
+		cl->dev = dev;
+		cl->tx_block = false;
+		cl->knows_txdone = true;
+		cl->rx_callback = imx_scu_rx_callback;
+
+		if (!sc_ipc->fast_ipc) {
+			/* Initial tx_done completion as "done" */
+			cl->tx_done = imx_scu_tx_done;
+			init_completion(&sc_chan->tx_done);
+			complete(&sc_chan->tx_done);
+		}
+
+		sc_chan->sc_ipc = sc_ipc;
+		sc_chan->idx = i % (num_channel / 2);
+		sc_chan->ch = mbox_request_channel_byname(cl, chan_name);
+		if (IS_ERR(sc_chan->ch)) {
+			ret = PTR_ERR(sc_chan->ch);
+			if (ret != -EPROBE_DEFER)
+				dev_err(dev, "Failed to request mbox chan %s ret %d\n",
+					chan_name, ret);
+			kfree(chan_name);
+			return ret;
+		}
+
+		dev_dbg(dev, "request mbox chan %s\n", chan_name);
+		/* chan_name is not used anymore by framework */
+		kfree(chan_name);
+	}
+
+	sc_ipc->dev = dev;
+	mutex_init(&sc_ipc->lock);
+	init_completion(&sc_ipc->done);
+
+	imx_sc_ipc_handle = sc_ipc;
+
+	ret = imx_scu_soc_init(dev);
+	if (ret)
+		dev_warn(dev, "failed to initialize SoC info: %d\n", ret);
+
+	ret = imx_scu_enable_general_irq_channel(dev);
+	if (ret)
+		dev_warn(dev,
+			"failed to enable general irq channel: %d\n", ret);
+
+	dev_info(dev, "NXP i.MX SCU Initialized\n");
+
+	return devm_of_platform_populate(dev);
+}
+
+static const struct of_device_id imx_scu_match[] = {
+	{ .compatible = "fsl,imx-scu", },
+	{ /* Sentinel */ }
+};
+
+static struct platform_driver imx_scu_driver = {
+	.driver = {
+		.name = "imx-scu",
+		.of_match_table = imx_scu_match,
+	},
+	.probe = imx_scu_probe,
+};
+builtin_platform_driver(imx_scu_driver);
+
+MODULE_AUTHOR("Dong Aisheng <aisheng.dong@nxp.com>");
+MODULE_DESCRIPTION("IMX SCU firmware protocol driver");
+MODULE_LICENSE("GPL v2");