6 files changed, 194 insertions, 2 deletions

diff --git a/drivers/firmware/imx/Kconfig b/drivers/firmware/imx/Kconfig
index 42b566f8903f..1d2e5b85d7ca 100644
--- a/drivers/firmware/imx/Kconfig
+++ b/drivers/firmware/imx/Kconfig
@@ -1,4 +1,15 @@
 # SPDX-License-Identifier: GPL-2.0-only
+config IMX_DSP
+	tristate "IMX DSP Protocol driver"
+	depends on IMX_MBOX
+	help
+	  This enables DSP IPC protocol between host AP (Linux)
+	  and the firmware running on DSP.
+	  DSP exists on some i.MX8 processors (e.g i.MX8QM, i.MX8QXP).
+
+	  It acts like a doorbell. Client might use shared memory to
+	  exchange information with DSP side.
+
 config IMX_SCU
 	bool "IMX SCU Protocol driver"
 	depends on IMX_MBOX
diff --git a/drivers/firmware/imx/Makefile b/drivers/firmware/imx/Makefile
index 802c4ad8e8f9..08bc9ddfbdfb 100644
--- a/drivers/firmware/imx/Makefile
+++ b/drivers/firmware/imx/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_IMX_DSP)		+= imx-dsp.o
 obj-$(CONFIG_IMX_SCU)		+= imx-scu.o misc.o imx-scu-irq.o
 obj-$(CONFIG_IMX_SCU_PD)	+= scu-pd.o
diff --git a/drivers/firmware/imx/imx-dsp.c b/drivers/firmware/imx/imx-dsp.c
new file mode 100644
index 000000000000..4265e9dbed84
--- /dev/null
+++ b/drivers/firmware/imx/imx-dsp.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2019 NXP
+ *  Author: Daniel Baluta <daniel.baluta@nxp.com>
+ *
+ * Implementation of the DSP IPC interface (host side)
+ */
+
+#include <linux/firmware/imx/dsp.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+/*
+ * imx_dsp_ring_doorbell - triggers an interrupt on the other side (DSP)
+ *
+ * @dsp: DSP IPC handle
+ * @chan_idx: index of the channel where to trigger the interrupt
+ *
+ * Returns non-negative value for success, negative value for error
+ */
+int imx_dsp_ring_doorbell(struct imx_dsp_ipc *ipc, unsigned int idx)
+{
+	int ret;
+	struct imx_dsp_chan *dsp_chan;
+
+	if (idx >= DSP_MU_CHAN_NUM)
+		return -EINVAL;
+
+	dsp_chan = &ipc->chans[idx];
+	ret = mbox_send_message(dsp_chan->ch, NULL);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL(imx_dsp_ring_doorbell);
+
+/*
+ * imx_dsp_handle_rx - rx callback used by imx mailbox
+ *
+ * @c: mbox client
+ * @msg: message received
+ *
+ * Users of DSP IPC will need to privde handle_reply and handle_request
+ * callbacks.
+ */
+static void imx_dsp_handle_rx(struct mbox_client *c, void *msg)
+{
+	struct imx_dsp_chan *chan = container_of(c, struct imx_dsp_chan, cl);
+
+	if (chan->idx == 0) {
+		chan->ipc->ops->handle_reply(chan->ipc);
+	} else {
+		chan->ipc->ops->handle_request(chan->ipc);
+		imx_dsp_ring_doorbell(chan->ipc, 1);
+	}
+}
+
+static int imx_dsp_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct imx_dsp_ipc *dsp_ipc;
+	struct imx_dsp_chan *dsp_chan;
+	struct mbox_client *cl;
+	char *chan_name;
+	int ret;
+	int i, j;
+
+	device_set_of_node_from_dev(&pdev->dev, pdev->dev.parent);
+
+	dsp_ipc = devm_kzalloc(dev, sizeof(*dsp_ipc), GFP_KERNEL);
+	if (!dsp_ipc)
+		return -ENOMEM;
+
+	for (i = 0; i < DSP_MU_CHAN_NUM; i++) {
+		if (i < 2)
+			chan_name = kasprintf(GFP_KERNEL, "txdb%d", i);
+		else
+			chan_name = kasprintf(GFP_KERNEL, "rxdb%d", i - 2);
+
+		if (!chan_name)
+			return -ENOMEM;
+
+		dsp_chan = &dsp_ipc->chans[i];
+		cl = &dsp_chan->cl;
+		cl->dev = dev;
+		cl->tx_block = false;
+		cl->knows_txdone = true;
+		cl->rx_callback = imx_dsp_handle_rx;
+
+		dsp_chan->ipc = dsp_ipc;
+		dsp_chan->idx = i % 2;
+		dsp_chan->ch = mbox_request_channel_byname(cl, chan_name);
+		if (IS_ERR(dsp_chan->ch)) {
+			ret = PTR_ERR(dsp_chan->ch);
+			if (ret != -EPROBE_DEFER)
+				dev_err(dev, "Failed to request mbox chan %s ret %d\n",
+					chan_name, ret);
+			goto out;
+		}
+
+		dev_dbg(dev, "request mbox chan %s\n", chan_name);
+		/* chan_name is not used anymore by framework */
+		kfree(chan_name);
+	}
+
+	dsp_ipc->dev = dev;
+
+	dev_set_drvdata(dev, dsp_ipc);
+
+	dev_info(dev, "NXP i.MX DSP IPC initialized\n");
+
+	return 0;
+out:
+	kfree(chan_name);
+	for (j = 0; j < i; j++) {
+		dsp_chan = &dsp_ipc->chans[j];
+		mbox_free_channel(dsp_chan->ch);
+	}
+
+	return ret;
+}
+
+static int imx_dsp_remove(struct platform_device *pdev)
+{
+	struct imx_dsp_chan *dsp_chan;
+	struct imx_dsp_ipc *dsp_ipc;
+	int i;
+
+	dsp_ipc = dev_get_drvdata(&pdev->dev);
+
+	for (i = 0; i < DSP_MU_CHAN_NUM; i++) {
+		dsp_chan = &dsp_ipc->chans[i];
+		mbox_free_channel(dsp_chan->ch);
+	}
+
+	return 0;
+}
+
+static struct platform_driver imx_dsp_driver = {
+	.driver = {
+		.name = "imx-dsp",
+	},
+	.probe = imx_dsp_probe,
+	.remove = imx_dsp_remove,
+};
+builtin_platform_driver(imx_dsp_driver);
+
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta@nxp.com>");
+MODULE_DESCRIPTION("IMX DSP IPC protocol driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/firmware/imx/imx-scu-irq.c b/drivers/firmware/imx/imx-scu-irq.c
index 687121f8c4d5..db655e87cdc8 100644
--- a/drivers/firmware/imx/imx-scu-irq.c
+++ b/drivers/firmware/imx/imx-scu-irq.c
@@ -8,6 +8,7 @@
 
 #include <dt-bindings/firmware/imx/rsrc.h>
 #include <linux/firmware/imx/ipc.h>
+#include <linux/firmware/imx/sci.h>
 #include <linux/mailbox_client.h>
 
 #define IMX_SC_IRQ_FUNC_ENABLE	1
diff --git a/drivers/firmware/imx/imx-scu.c b/drivers/firmware/imx/imx-scu.c
index 04a24a863d6e..03b43b7a6d1d 100644
--- a/drivers/firmware/imx/imx-scu.c
+++ b/drivers/firmware/imx/imx-scu.c
@@ -107,6 +107,12 @@ static void imx_scu_rx_callback(struct mbox_client *c, void *msg)
 	struct imx_sc_rpc_msg *hdr;
 	u32 *data = msg;
 
+	if (!sc_ipc->msg) {
+		dev_warn(sc_ipc->dev, "unexpected rx idx %d 0x%08x, ignore!\n",
+				sc_chan->idx, *data);
+		return;
+	}
+
 	if (sc_chan->idx == 0) {
 		hdr = msg;
 		sc_ipc->rx_size = hdr->size;
@@ -156,6 +162,7 @@ static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
  */
 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;
 
@@ -165,7 +172,11 @@ int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp)
 	mutex_lock(&sc_ipc->lock);
 	reinit_completion(&sc_ipc->done);
 
-	sc_ipc->msg = msg;
+	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) {
@@ -184,9 +195,20 @@ int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp)
 		/* 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");
diff --git a/drivers/firmware/imx/scu-pd.c b/drivers/firmware/imx/scu-pd.c
index 480cec69e2c9..b556612207e5 100644
--- a/drivers/firmware/imx/scu-pd.c
+++ b/drivers/firmware/imx/scu-pd.c
@@ -92,7 +92,8 @@ static const struct imx_sc_pd_range imx8qxp_scu_pd_ranges[] = {
 	{ "gpt", IMX_SC_R_GPT_0, 5, true, 0 },
 	{ "kpp", IMX_SC_R_KPP, 1, false, 0 },
 	{ "fspi", IMX_SC_R_FSPI_0, 2, true, 0 },
-	{ "mu", IMX_SC_R_MU_0A, 14, true, 0 },
+	{ "mu_a", IMX_SC_R_MU_0A, 14, true, 0 },
+	{ "mu_b", IMX_SC_R_MU_13B, 1, true, 13 },
 
 	/* CONN SS */
 	{ "usb", IMX_SC_R_USB_0, 2, true, 0 },
@@ -130,6 +131,7 @@ static const struct imx_sc_pd_range imx8qxp_scu_pd_ranges[] = {
 	{ "lcd0-pwm", IMX_SC_R_LCD_0_PWM_0, 1, true, 0 },
 	{ "lpuart", IMX_SC_R_UART_0, 4, true, 0 },
 	{ "lpspi", IMX_SC_R_SPI_0, 4, true, 0 },
+	{ "irqstr_dsp", IMX_SC_R_IRQSTR_DSP, 1, false, 0 },
 
 	/* VPU SS */
 	{ "vpu", IMX_SC_R_VPU, 1, false, 0 },