modem: Add M6718 IPC SPI driver utilities

Adds utility functions to be used by the IPC protocol.

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

Change-Id: I27a1329b980f69671c7ae7f2c975ade80d6aa409
Signed-off-by: Chris Blair <chris.blair@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/36479
Reviewed-by: QATOOLS
Reviewed-by: QABUILD
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>

4 files changed, 372 insertions, 1 deletions

diff --git a/drivers/modem/m6718_spi/Makefile b/drivers/modem/m6718_spi/Makefile
index 66bad09c0dd..ea14319ad7d 100644
--- a/drivers/modem/m6718_spi/Makefile
+++ b/drivers/modem/m6718_spi/Makefile
@@ -5,7 +5,7 @@ ifeq ($(CONFIG_MODEM_M6718_SPI_DEBUG),y)
 EXTRA_CFLAGS += -DDEBUG
 endif
 
-m6718_modem_spi-objs := modem_driver.o protocol.o
+m6718_modem_spi-objs := modem_driver.o protocol.o util.o
 
 ifeq ($(CONFIG_MODEM_M6718_SPI_ENABLE_FEATURE_MODEM_STATE),y)
 m6718_modem_spi-objs += modem_state.o
diff --git a/drivers/modem/m6718_spi/modem_util.h b/drivers/modem/m6718_spi/modem_util.h
new file mode 100644
index 00000000000..3219900a3c8
--- /dev/null
+++ b/drivers/modem/m6718_spi/modem_util.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2011
+ *
+ * Author: Chris Blair <chris.blair@stericsson.com> for ST-Ericsson
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * Modem IPC driver protocol interface header:
+ *   utility functionality.
+ */
+#ifndef _MODEM_UTIL_H_
+#define _MODEM_UTIL_H_
+
+#include <linux/kernel.h>
+#include "modem_private.h"
+
+bool ipc_util_channel_is_loopback(u8 channel);
+
+u32 ipc_util_make_l2_header(u8 channel, u32 len);
+u8 ipc_util_get_l2_channel(u32 hdr);
+u32 ipc_util_get_l2_length(u32 hdr);
+u32 ipc_util_make_l1_header(u8 cmd, u8 counter, u32 len);
+u8 ipc_util_get_l1_cmd(u32 hdr);
+u8 ipc_util_get_l1_counter(u32 hdr);
+u32 ipc_util_get_l1_length(u32 hdr);
+u8 ipc_util_get_l1_bootresp_ver(u32 bootresp);
+
+int ipc_util_ss_level_active(struct ipc_link_context *context);
+int ipc_util_ss_level_inactive(struct ipc_link_context *context);
+int ipc_util_int_level_active(struct ipc_link_context *context);
+int ipc_util_int_level_inactive(struct ipc_link_context *context);
+
+void ipc_util_deactivate_ss(struct ipc_link_context *context);
+void ipc_util_activate_ss(struct ipc_link_context *context);
+void ipc_util_activate_ss_with_tmo(struct ipc_link_context *context);
+
+bool ipc_util_int_is_active(struct ipc_link_context *context);
+
+bool ipc_util_link_is_idle(struct ipc_link_context *context);
+
+void ipc_util_start_slave_stable_timer(struct ipc_link_context *context);
+
+void ipc_util_spi_message_prepare(struct ipc_link_context *link_context,
+	void *tx_buf, void *rx_buf, int len);
+void ipc_util_spi_message_init(struct ipc_link_context *link_context,
+	void (*complete)(void *));
+
+bool ipc_util_link_gpio_request(struct ipc_link_context *context,
+	irqreturn_t (*irqhnd)(int, void *));
+bool ipc_util_link_gpio_config(struct ipc_link_context *context);
+bool ipc_util_link_gpio_unconfig(struct ipc_link_context *context);
+
+#endif /* _MODEM_UTIL_H_ */
diff --git a/drivers/modem/m6718_spi/protocol.c b/drivers/modem/m6718_spi/protocol.c
index 5f03167d024..6879d58798b 100644
--- a/drivers/modem/m6718_spi/protocol.c
+++ b/drivers/modem/m6718_spi/protocol.c
@@ -10,6 +10,7 @@
 #include <linux/modem/m6718_spi/modem_driver.h>
 #include "modem_protocol.h"
 #include "modem_private.h"
+#include "modem_util.h"
 
 #ifdef CONFIG_MODEM_M6718_SPI_ENABLE_FEATURE_MODEM_STATE
 #include <linux/workqueue.h>
@@ -177,16 +178,53 @@ bool modem_protocol_is_busy(struct spi_device *sdev)
 	return false;
 }
 
+static void spi_tfr_complete(void *context)
+{
+	/* TODO: statemachine will be kicked here */
+}
+
+static irqreturn_t slave_ready_irq(int irq, void *dev)
+{
+	struct ipc_link_context *context = (struct ipc_link_context *)dev;
+	struct modem_m6718_spi_link_platform_data *link = context->link;
+	struct spi_device *sdev = context->sdev;
+
+	if (irq != GPIO_TO_IRQ(link->gpio.int_pin)) {
+		dev_err(&sdev->dev,
+			"link %d error: spurious slave irq!", link->id);
+		return IRQ_NONE;
+	}
+
+#ifdef WORKAROUND_DUPLICATED_IRQ
+	if (link->id != IPC_LINK_AUDIO && pl022_tfr_in_progress(sdev)) {
+		dev_warn(&sdev->dev,
+			"link %d warning: slave irq while transfer "
+			"is active! discarding event\n", link->id);
+		return IRQ_HANDLED;
+	}
+#endif
+	/* TODO: statemachine will be kicked here */
+	return IRQ_HANDLED;
+}
+
 #ifdef CONFIG_MODEM_M6718_SPI_ENABLE_FEATURE_MODEM_STATE
 static int modem_state_callback(unsigned long unused)
 {
 	int modem_state = modem_state_get_state();
+	struct ipc_link_context *contexts = l1_context.device_context;
+	u8 i;
 
 	pr_info("M6718 IPC protocol modemstate reports modem is %s\n",
 		modem_state_to_str(modem_state));
 
 	switch (modem_state) {
 	case MODEM_STATE_ON:
+		/*
+		 * Modem is on, ensure each link is configured and trigger
+		 * a state change on link0 to begin handshake.
+		 */
+		for (i = 0; i < IPC_NBR_SUPPORTED_SPI_LINKS; i++)
+			ipc_util_link_gpio_config(&contexts[i]);
 		/* TODO: statemachine will be kicked here */
 		break;
 	case MODEM_STATE_OFF:
@@ -248,7 +286,10 @@ int modem_protocol_probe(struct spi_device *sdev)
 	context->link = link;
 	context->sdev = sdev;
 	atomic_set(&context->gpio_configured, 0);
+	atomic_set(&context->state_int,
+		ipc_util_int_level_inactive(context));
 	spin_lock_init(&context->sm_lock);
+	ipc_util_spi_message_init(context, spi_tfr_complete);
 	init_timer(&context->comms_timer);
 	context->comms_timer.function = modem_comms_timeout;
 	context->comms_timer.data = (unsigned long)context;
@@ -256,6 +297,11 @@ int modem_protocol_probe(struct spi_device *sdev)
 	context->slave_stable_timer.function = slave_stable_timeout;
 	context->slave_stable_timer.data = (unsigned long)context;
 
+	if (!ipc_util_link_gpio_request(context, slave_ready_irq))
+		return -ENODEV;
+	if (!ipc_util_link_gpio_config(context))
+		return -ENODEV;
+
 #ifdef CONFIG_MODEM_M6718_SPI_ENABLE_FEATURE_VERIFY_FRAMES
 	context->last_frame = NULL;
 #endif
@@ -283,5 +329,9 @@ int modem_protocol_probe(struct spi_device *sdev)
 
 void modem_protocol_exit(void)
 {
+	int i;
+
 	pr_info("M6718 IPC protocol exit\n");
+	for (i = 0; i < IPC_NBR_SUPPORTED_SPI_LINKS; i++)
+		ipc_util_link_gpio_unconfig(&l1_context.device_context[i]);
 }
diff --git a/drivers/modem/m6718_spi/util.c b/drivers/modem/m6718_spi/util.c
new file mode 100644
index 00000000000..43862baff99
--- /dev/null
+++ b/drivers/modem/m6718_spi/util.c
@@ -0,0 +1,268 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2010,2011
+ *
+ * Author: Chris Blair <chris.blair@stericsson.com> for ST-Ericsson
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * U9500 <-> M6718 IPC protocol implementation using SPI:
+ *   utility functions.
+ */
+#include <linux/gpio.h>
+#include <linux/modem/m6718_spi/modem_driver.h>
+#include "modem_util.h"
+
+#define MODEM_COMMS_TMO_MS  (5000) /* 0 == no timeout */
+#define SLAVE_STABLE_TMO_MS (1000)
+
+#define DRIVER_NAME "ipcspi" /* name used when reserving gpio pins */
+
+
+bool ipc_util_channel_is_loopback(u8 channel)
+{
+	return channel == MODEM_M6718_SPI_CHN_MASTER_LOOPBACK0 ||
+		channel == MODEM_M6718_SPI_CHN_MASTER_LOOPBACK1;
+}
+
+u32 ipc_util_make_l2_header(u8 channel, u32 len)
+{
+	return ((channel & 0xf) << 28) | (len & 0x000fffff);
+}
+
+u8 ipc_util_get_l2_channel(u32 hdr)
+{
+	return hdr >> 28;
+}
+
+u32 ipc_util_get_l2_length(u32 hdr)
+{
+	return hdr & 0x000fffff;
+}
+
+u32 ipc_util_make_l1_header(u8 cmd, u8 counter, u32 len)
+{
+	return (cmd << 28) |
+		((counter & 0x000000ff) << 20) |
+		(len & 0x000fffff);
+}
+
+u8 ipc_util_get_l1_cmd(u32 hdr)
+{
+	return hdr >> 28;
+}
+
+u8 ipc_util_get_l1_counter(u32 hdr)
+{
+	return (hdr >> 20) & 0x000000ff;
+}
+
+u32 ipc_util_get_l1_length(u32 hdr)
+{
+	return hdr & 0x000fffff;
+}
+
+u8 ipc_util_get_l1_bootresp_ver(u32 bootresp)
+{
+	return bootresp & 0x000000ff;
+}
+
+int ipc_util_ss_level_active(struct ipc_link_context *context)
+{
+	return context->link->gpio.ss_active == 0 ? 0 : 1;
+}
+
+int ipc_util_ss_level_inactive(struct ipc_link_context *context)
+{
+	return !ipc_util_ss_level_active(context);
+}
+
+int ipc_util_int_level_active(struct ipc_link_context *context)
+{
+	return context->link->gpio.int_active == 0 ? 0 : 1;
+}
+
+int ipc_util_int_level_inactive(struct ipc_link_context *context)
+{
+	return !ipc_util_int_level_active(context);
+}
+
+void ipc_util_deactivate_ss(struct ipc_link_context *context)
+{
+	gpio_set_value(context->link->gpio.ss_pin,
+		ipc_util_ss_level_inactive(context));
+
+	dev_dbg(&context->sdev->dev,
+		"link %d: deactivated SS\n", context->link->id);
+}
+
+void ipc_util_activate_ss(struct ipc_link_context *context)
+{
+	gpio_set_value(context->link->gpio.ss_pin,
+		ipc_util_ss_level_active(context));
+
+	dev_dbg(&context->sdev->dev,
+		"link %d: activated SS\n", context->link->id);
+}
+
+void ipc_util_activate_ss_with_tmo(struct ipc_link_context *context)
+{
+	gpio_set_value(context->link->gpio.ss_pin,
+		ipc_util_ss_level_active(context));
+
+#if MODEM_COMMS_TMO_MS == 0
+	dev_dbg(&context->sdev->dev,
+		 "link %d: activated SS (timeout is disabled)\n",
+		 context->link->id);
+#else
+	context->comms_timer.expires = jiffies +
+		((MODEM_COMMS_TMO_MS * HZ) / 1000);
+	add_timer(&context->comms_timer);
+
+	dev_dbg(&context->sdev->dev,
+		"link %d: activated SS with timeout\n", context->link->id);
+#endif
+}
+
+bool ipc_util_int_is_active(struct ipc_link_context *context)
+{
+	return gpio_get_value(context->link->gpio.int_pin) ==
+		ipc_util_int_level_active(context);
+}
+
+bool ipc_util_link_is_idle(struct ipc_link_context *context)
+{
+	if (context->state == NULL)
+		return false;
+
+	switch (context->state->id) {
+	case IPC_SM_IDL:
+	case IPC_SM_IDL_AUD:
+		return true;
+	default:
+		return false;
+	}
+}
+
+void ipc_util_start_slave_stable_timer(struct ipc_link_context *context)
+{
+	context->slave_stable_timer.expires =
+		jiffies + ((SLAVE_STABLE_TMO_MS * HZ) / 1000);
+	add_timer(&context->slave_stable_timer);
+}
+
+void ipc_util_spi_message_prepare(struct ipc_link_context *link_context,
+	void *tx_buf, void *rx_buf, int len)
+{
+	struct spi_transfer *tfr = &link_context->spi_transfer;
+	struct spi_message *msg = &link_context->spi_message;
+
+	tfr->tx_buf = tx_buf;
+	tfr->rx_buf = rx_buf;
+	tfr->len    = len;
+	msg->context = link_context;
+}
+
+void ipc_util_spi_message_init(struct ipc_link_context *link_context,
+	void (*complete)(void *))
+{
+	struct spi_message *msg = &link_context->spi_message;
+	struct spi_transfer *tfr = &link_context->spi_transfer;
+
+	tfr->bits_per_word = 16;
+
+	/* common init of transfer - use default from board device */
+	tfr->cs_change = 0;
+	tfr->speed_hz = 0;
+	tfr->delay_usecs = 0;
+
+	/* common init of message */
+	spi_message_init(msg);
+	msg->spi = link_context->sdev;
+	msg->complete = complete;
+	spi_message_add_tail(tfr, msg);
+}
+
+bool ipc_util_link_gpio_request(struct ipc_link_context *context,
+	irqreturn_t (*irqhnd)(int, void*))
+{
+	struct spi_device *sdev = context->sdev;
+	struct modem_m6718_spi_link_platform_data *link = context->link;
+	unsigned long irqflags;
+
+	if (gpio_request(link->gpio.ss_pin, DRIVER_NAME) < 0) {
+		dev_err(&sdev->dev,
+			"link %d error: failed to get gpio %d for SS pin\n",
+			link->id,
+			link->gpio.ss_pin);
+		return false;
+	}
+	if (gpio_request(link->gpio.int_pin, DRIVER_NAME) < 0) {
+		dev_err(&sdev->dev,
+			"link %d error: failed to get gpio %d for INT pin\n",
+			link->id,
+			link->gpio.int_pin);
+		return false;
+	}
+
+	if (ipc_util_int_level_active(context) == 1)
+		irqflags = IRQF_TRIGGER_RISING;
+	else
+		irqflags = IRQF_TRIGGER_FALLING;
+
+	if (request_irq(GPIO_TO_IRQ(link->gpio.int_pin),
+			irqhnd,
+			irqflags,
+			DRIVER_NAME,
+			context) < 0) {
+		dev_err(&sdev->dev,
+			"link %d error: could not get irq %d\n",
+			link->id, GPIO_TO_IRQ(link->gpio.int_pin));
+		return false;
+	}
+	return true;
+}
+
+bool ipc_util_link_gpio_config(struct ipc_link_context *context)
+{
+	struct spi_device *sdev = context->sdev;
+	struct modem_m6718_spi_link_platform_data *link = context->link;
+
+	if (atomic_read(&context->gpio_configured) == 1)
+		return true;
+
+	dev_dbg(&sdev->dev, "link %d: configuring GPIO\n", link->id);
+
+	ipc_util_deactivate_ss(context);
+	gpio_direction_input(link->gpio.int_pin);
+	if (enable_irq_wake(GPIO_TO_IRQ(link->gpio.int_pin)) < 0) {
+		dev_err(&sdev->dev,
+			"link %d error: failed to enable wake on INT\n",
+			link->id);
+		return false;
+	}
+
+	atomic_set(&context->state_int, gpio_get_value(link->gpio.int_pin));
+	atomic_set(&context->gpio_configured, 1);
+	return true;
+}
+
+bool ipc_util_link_gpio_unconfig(struct ipc_link_context *context)
+{
+	struct spi_device *sdev = context->sdev;
+	struct modem_m6718_spi_link_platform_data *link = context->link;
+
+	if (atomic_read(&context->gpio_configured) == 0)
+		return true;
+
+	dev_dbg(&sdev->dev, "link %d: un-configuring GPIO\n", link->id);
+
+	/* SS: output anyway, just make sure it is low */
+	gpio_set_value(link->gpio.ss_pin, 0);
+
+	/* INT: disable system-wake, reconfigure as output-low */
+	disable_irq_wake(GPIO_TO_IRQ(link->gpio.int_pin));
+	gpio_direction_output(link->gpio.int_pin, 0);
+	atomic_set(&context->gpio_configured, 0);
+	return true;
+}
+