modem: Add M6718 modem SPI IPC driver framework

Adds support for the M6718 modem IPC SPI driver. This patch adds the
spi driver under which the protocol will be added.

ST-Ericsson ID: 369397
ST-Ericsson FOSS-OUT ID: STETL-FOSS-OUT-12224
ST-Ericsson Linux next: NA

Change-Id: Ifa60efa9cb6a9d30b02b88b563624a293bc0930c
Signed-off-by: Chris Blair <chris.blair@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/36433
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>

6 files changed, 365 insertions, 0 deletions

diff --git a/drivers/modem/Kconfig b/drivers/modem/Kconfig
index 9ecbe00fd61..323ef88af18 100644
--- a/drivers/modem/Kconfig
+++ b/drivers/modem/Kconfig
@@ -29,3 +29,5 @@ config MODEM_M6718
 	 Add support for the modem access driver for the M6718 modem.
 
 	 If unsure, say N.
+
+source "drivers/modem/m6718_spi/Kconfig"
diff --git a/drivers/modem/Makefile b/drivers/modem/Makefile
index c0df71e65a1..a7c1df50074 100644
--- a/drivers/modem/Makefile
+++ b/drivers/modem/Makefile
@@ -2,3 +2,4 @@ obj-$(CONFIG_MODEM)       := modem_access.o
 obj-$(CONFIG_MODEM_U8500) += modem_u8500.o
 obj-$(CONFIG_U8500_SHRM)  += shrm/
 obj-$(CONFIG_MODEM_M6718) += modem_m6718.o
+obj-$(CONFIG_MODEM_M6718_SPI) += m6718_spi/
diff --git a/drivers/modem/m6718_spi/Kconfig b/drivers/modem/m6718_spi/Kconfig
new file mode 100644
index 00000000000..f945d24a094
--- /dev/null
+++ b/drivers/modem/m6718_spi/Kconfig
@@ -0,0 +1,83 @@
+#
+# M6718 modem SPI IPC driver kernel configuration
+#
+config MODEM_M6718_SPI
+	tristate "M6718 modem IPC SPI driver"
+	depends on MODEM_M6718
+	default y
+	---help---
+	  If you say Y here, you will enable the M6718 modem IPC SPI driver.
+
+	  If unsure, say Y.
+
+config MODEM_M6718_SPI_DEBUG
+	boolean "Modem driver debug"
+	depends on MODEM_M6718_SPI
+	default N
+	---help---
+	   If you say Y here, you will enable full debug trace from the M6718
+	   modem driver.  This should not be enabled by default.
+
+	   If unsure, say N.
+
+config MODEM_M6718_SPI_ENABLE_FEATURE_MODEM_STATE
+	boolean "M6718 modem state driver integration"
+	depends on MODEM_M6718_SPI
+	default y
+	---help---
+	  Enables integration of the IPC driver with the modem state driver.
+	  This allows the IPC driver to be notified of changes in modem state
+	  (on, off, reset) and allows the IPC driver to cause modem state
+	  changes if needed.
+
+	  By default this should be enabled.
+
+config MODEM_M6718_SPI_ENABLE_FEATURE_FRAME_DUMP
+	boolean "IPC SPI L1 frame dump"
+	depends on MODEM_M6718_SPI
+	default n
+	---help---
+	  If you say Y here, you will enable dumping of the raw TX and RX frames
+	  by the IPC driver L1.
+
+	  If unsure, say N.
+
+config MODEM_M6718_SPI_ENABLE_FEATURE_LOOPBACK
+	boolean "Modem IPC loopback support"
+	depends on MODEM_M6718_SPI
+	default y
+	---help---
+	  If you say Y here, you will enable the IPC loopback channels/devices.
+
+	  If unsure, say Y.
+
+
+config MODEM_M6718_SPI_ENABLE_FEATURE_VERIFY_FRAMES
+	boolean "Verify loopback frames"
+	depends on MODEM_M6718_SPI
+	default n
+	---help---
+	  This will enabling checking of loopback frames to verify that the data
+	  received is identical to the data sent.
+
+	  If unsure, say N.
+
+config MODEM_M6718_SPI_ENABLE_FEATURE_THROUGHPUT_MEASUREMENT
+	boolean "Modem IPC throughput measurement"
+	depends on MODEM_M6718_SPI
+	default n
+	---help---
+	  If you say Y here, you will enable the IPC link throughput
+	  measurement and reporting.
+
+	  If unsure, say N.
+
+config MODEM_M6718_SPI_SET_THROUGHPUT_FREQUENCY
+	int "Sample rate for throughput measurements (seconds)"
+	default "5"
+	depends on MODEM_M6718_SPI_ENABLE_FEATURE_THROUGHPUT_MEASUREMENT
+	help
+	  The sample frequency for taking IPC SPI link throughput measurements.
+	  Increasing the rate (reducing the time) will increase the accuracy of
+	  the measurements, but will also increase the impact on link and system
+	  performance.
diff --git a/drivers/modem/m6718_spi/Makefile b/drivers/modem/m6718_spi/Makefile
new file mode 100644
index 00000000000..96bf481e986
--- /dev/null
+++ b/drivers/modem/m6718_spi/Makefile
@@ -0,0 +1,10 @@
+#
+# Makefile for M6718 SPI driver
+#
+ifeq ($(CONFIG_MODEM_M6718_SPI_DEBUG),y)
+EXTRA_CFLAGS += -DDEBUG
+endif
+
+m6718_modem_spi-objs := modem_driver.o
+
+obj-$(CONFIG_MODEM_M6718_SPI) += m6718_modem_spi.o
diff --git a/drivers/modem/m6718_spi/modem_driver.c b/drivers/modem/m6718_spi/modem_driver.c
new file mode 100644
index 00000000000..7d0efa6e395
--- /dev/null
+++ b/drivers/modem/m6718_spi/modem_driver.c
@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2011
+ *
+ * Author: Chris Blair <chris.blair@stericsson.com> for ST-Ericsson
+ *   based on modem_shrm_driver.c
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * SPI driver implementing the M6718 inter-processor communication protocol.
+ */
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/spi/spi.h>
+#include <linux/modem/modem_client.h>
+#include <linux/modem/m6718_spi/modem_driver.h>
+
+static struct modem_spi_dev modem_driver_data = {
+	.dev = NULL,
+	.ndev = NULL,
+	.modem = NULL,
+	.isa_context = NULL,
+	.netdev_flag_up = 0
+};
+
+/**
+ * modem_m6718_spi_receive() - Receive a frame from L1 physical layer
+ * @sdev:	pointer to spi device structure
+ * @channel:	L2 mux channel id
+ * @len:	frame data length
+ * @data:	pointer to frame data
+ *
+ * This function is called from the driver L1 physical transport layer. It
+ * copied the frame data to the receive queue for the channel on which the data
+ * was received.
+ *
+ * Special handling is given to slave-loopback channels where the data is simply
+ * sent back to the modem on the same channel.
+ *
+ * Special handling is given to the ISI channel when PHONET is enabled - the
+ * phonet tasklet is scheduled in order to pump the received data through the
+ * net device interface.
+ */
+int modem_m6718_spi_receive(struct spi_device *sdev, u8 channel,
+	u32 len, void *data)
+{
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(modem_m6718_spi_receive);
+
+static int spi_probe(struct spi_device *sdev)
+{
+	int result = 0;
+
+	spi_set_drvdata(sdev, &modem_driver_data);
+
+	/*
+	 * Since we can have multiple spi links for the same modem, only
+	 * initialise the modem data and char/net interfaces once.
+	 */
+	if (modem_driver_data.dev == NULL) {
+		modem_driver_data.dev = &sdev->dev;
+		modem_driver_data.modem =
+			modem_get(modem_driver_data.dev, "m6718");
+		if (modem_driver_data.modem == NULL) {
+			dev_err(&sdev->dev,
+				"failed to retrieve modem description\n");
+			result = -ENODEV;
+		}
+	}
+	return result;
+}
+
+static int __exit spi_remove(struct spi_device *sdev)
+{
+	return 0;
+}
+
+#ifdef CONFIG_PM
+/**
+ * spi_suspend() - This routine puts the IPC driver in to suspend state.
+ * @sdev: pointer to spi device structure.
+ * @mesg: pm operation
+ *
+ * This routine checks the current ongoing communication with modem
+ * and prevents suspend if modem communication is on-going.
+ */
+static int spi_suspend(struct spi_device *sdev, pm_message_t mesg)
+{
+	dev_dbg(&sdev->dev, "suspend called\n");
+	return 0;
+}
+
+/**
+ * spi_resume() - This routine resumes the IPC driver from suspend state.
+ * @sdev: pointer to spi device structure
+ */
+static int spi_resume(struct spi_device *sdev)
+{
+	dev_dbg(&sdev->dev, "resume called\n");
+	return 0;
+}
+#endif /* CONFIG_PM */
+
+static struct spi_driver spi_driver = {
+	.driver = {
+		.name = "spimodem",
+		.bus  = &spi_bus_type,
+		.owner = THIS_MODULE
+	},
+	.probe = spi_probe,
+	.remove = __exit_p(spi_remove),
+#ifdef CONFIG_PM
+	.suspend = spi_suspend,
+	.resume = spi_resume,
+#endif
+};
+
+static int __init m6718_spi_driver_init(void)
+{
+	pr_info("M6718 modem driver initialising\n");
+	return spi_register_driver(&spi_driver);
+}
+module_init(m6718_spi_driver_init);
+
+static void __exit m6718_spi_driver_exit(void)
+{
+	pr_debug("M6718 modem SPI IPC driver exit\n");
+	spi_unregister_driver(&spi_driver);
+}
+module_exit(m6718_spi_driver_exit);
+
+MODULE_AUTHOR("Chris Blair <chris.blair@stericsson.com>");
+MODULE_DESCRIPTION("M6718 modem IPC SPI driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/modem/m6718_spi/modem_driver.h b/include/linux/modem/m6718_spi/modem_driver.h
new file mode 100644
index 00000000000..8c5209c228c
--- /dev/null
+++ b/include/linux/modem/m6718_spi/modem_driver.h
@@ -0,0 +1,135 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2011
+ *
+ * Author: Chris Blair <chris.blair@stericsson.com> for ST-Ericsson
+ *   based on shrm_driver.h
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * Modem IPC driver interface header.
+ */
+#ifndef _MODEM_DRIVER_H_
+#define _MODEM_DRIVER_H_
+
+#include <linux/device.h>
+#include <linux/modem/modem.h>
+#include <linux/cdev.h>
+#include <linux/spi/spi.h>
+
+
+/* driver L2 mux channels */
+#ifdef CONFIG_MODEM_M6718_SPI_ENABLE_FEATURE_LOOPBACK
+#define MODEM_M6718_SPI_MAX_CHANNELS		(9)
+#else
+#define MODEM_M6718_SPI_MAX_CHANNELS		(3)
+#endif
+
+#define MODEM_M6718_SPI_CHN_ISI			(0)
+/*#define MODEM_M6718_SPI_CHN_RPC		(1) not supported */
+#define MODEM_M6718_SPI_CHN_AUDIO		(2)
+/*#define MODEM_M6718_SPI_CHN_SECURITY		(3) not supported */
+/*						(4) not supported */
+#ifdef CONFIG_MODEM_M6718_SPI_ENABLE_FEATURE_LOOPBACK
+#define MODEM_M6718_SPI_CHN_MASTER_LOOPBACK0	(5)
+#define MODEM_M6718_SPI_CHN_SLAVE_LOOPBACK0	(6)
+#define MODEM_M6718_SPI_CHN_MASTER_LOOPBACK1	(7)
+#define MODEM_M6718_SPI_CHN_SLAVE_LOOPBACK1	(8)
+#endif
+
+/**
+ * struct queue_element - information to add an element to queue
+ * @entry:	list entry
+ * @offset:	message offset
+ * @size:	message size
+ * @no:		total number of messages
+ */
+struct queue_element {
+	struct list_head entry;
+	u32 offset;
+	u32 size;
+	u32 no;
+};
+
+/**
+ * struct message_queue - ISI, RPC, AUDIO, SECURITY message queue information
+ * @channel:		L2 mux channel served by this queue
+ * @fifo_base:		pointer to the respective fifo base
+ * @size:		size of the data to be read
+ * @free:		free space in the queue
+ * @readptr:		fifo read pointer
+ * @writeptr:		fifo write pointer
+ * @no:			total number of messages
+ * @update_lock:	spinlock for protecting the queue read operation
+ * @q_rp:		queue read pointer is valid
+ * @wq_readable:	wait queue head
+ * @msg_list:		message list
+ * @modem_spi_dev:	pointer to modem device information structure
+ */
+struct message_queue {
+      u8 channel;
+      u8 *fifo_base;
+      u32 size;
+      u32 free;
+      u32 readptr;
+      u32 writeptr;
+      u32 no;
+      spinlock_t update_lock;
+      atomic_t q_rp;
+      wait_queue_head_t wq_readable;
+      struct list_head msg_list;
+      struct modem_spi_dev *modem_spi_dev;
+};
+
+/**
+ * struct isa_device_context - modem char interface device information
+ * @dl_queue:	structre to store the queue related info
+ * @device_id:	channel id (ISI, AUDIO, RPC, ...)
+ * @addr:	device address
+ */
+struct isa_device_context {
+	struct message_queue dl_queue;
+	u8 device_id;
+	void *addr;
+};
+
+/**
+ * struct isa_driver_context - modem char interface driver information
+ * @is_open:		flag to check the usage of queue
+ * @isadev:		pointer to struct t_isadev_context
+ * @common_tx_lock:	spinlock for protecting common channel
+ * @audio_tx_mutex:	mutex for protecting audio channel
+ * @cdev:		character device structre
+ * @modem_class:	pointer to the class structure
+ */
+struct isa_driver_context {
+	atomic_t is_open[MODEM_M6718_SPI_MAX_CHANNELS];
+	struct isa_device_context *isadev;
+	spinlock_t common_tx_lock;
+	struct mutex audio_tx_mutex;
+	struct cdev cdev;
+	struct class *modem_class;
+};
+
+/**
+ * struct modem_spi_dev - modem device information
+ * @dev			pointer to device
+ * @ndev		pointer to net_device interface
+ * @modem		pointer to registered modem structure
+ * @isa_context		pointer to char device interface
+ * @netdev_flag_up:	flag to indicate up/down of network device
+ * @msr_flag:		flag to indicate modem-silent-reset is in progress
+ */
+struct modem_spi_dev {
+	struct device *dev;
+	struct net_device *ndev;
+	struct modem *modem;
+	struct isa_driver_context *isa_context;
+	int netdev_flag_up;
+	bool msr_flag;
+};
+
+/* function exported for L1 to call with received frames */
+int modem_m6718_spi_receive(struct spi_device *sdev, u8 channel,
+	u32 len, void *data);
+
+#endif /* _MODEM_DRIVER_H_ */