Merge branch 'for-next/serdev'

3 files changed, 230 insertions, 3 deletions

diff --git a/common/Makefile b/common/Makefile
index 4e9681f203..1ff7d2370b 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -61,6 +61,7 @@ obj-$(CONFIG_FIRMWARE)		+= firmware.o
 obj-$(CONFIG_UBIFORMAT)		+= ubiformat.o
 obj-$(CONFIG_BAREBOX_UPDATE_IMX_NAND_FCB) += imx-bbu-nand-fcb.o
 obj-$(CONFIG_BOOT)		+= boot.o
+obj-$(CONFIG_SERIAL_DEV_BUS)	+= serdev.o
 
 ifdef CONFIG_PASSWORD
 
diff --git a/common/console.c b/common/console.c
index f4c799fa54..ab3d4d397c 100644
--- a/common/console.c
+++ b/common/console.c
@@ -305,10 +305,11 @@ static ssize_t fops_write(struct cdev* dev, const void* buf, size_t count,
 
 int console_register(struct console_device *newcdev)
 {
+	struct device_node *serdev_node = console_is_serdev_node(newcdev);
 	struct device_d *dev = &newcdev->class_dev;
 	int activate = 0, ret;
 
-	if (initialized == CONSOLE_UNINITIALIZED)
+	if (!serdev_node && initialized == CONSOLE_UNINITIALIZED)
 		console_init_early();
 
 	if (newcdev->devname) {
@@ -323,6 +324,17 @@ int console_register(struct console_device *newcdev)
 		dev->parent = newcdev->dev;
 	platform_device_register(dev);
 
+	newcdev->open_count = 0;
+
+	/*
+	 * If our console device is a serdev, we skip the creation of
+	 * corresponding entry in /dev as well as registration in
+	 * console_list and just go straight to populating child
+	 * devices.
+	 */
+	if (serdev_node)
+		return of_platform_populate(serdev_node, NULL, dev);
+
 	if (newcdev->setbrg) {
 		ret = newcdev->setbrg(newcdev, CONFIG_BAUDRATE);
 		if (ret)
@@ -335,8 +347,6 @@ int console_register(struct console_device *newcdev)
 	if (newcdev->putc && !newcdev->puts)
 		newcdev->puts = __console_puts;
 
-	newcdev->open_count = 0;
-
 	dev_add_param_string(dev, "active", console_active_set, console_active_get,
 			     &newcdev->active_string, newcdev);
 
@@ -386,6 +396,14 @@ int console_unregister(struct console_device *cdev)
 	struct device_d *dev = &cdev->class_dev;
 	int status;
 
+	/*
+	 * We don't do any sophisticated serdev device de-population
+	 * and instead claim this console busy, preventing its
+	 * de-initialization, 'till the very end of our execution.
+	 */
+	if (console_is_serdev_node(cdev))
+		return -EBUSY;
+
 	devfs_remove(&cdev->devfs);
 
 	list_del(&cdev->list);
diff --git a/common/serdev.c b/common/serdev.c
new file mode 100644
index 0000000000..4a6dbefe61
--- /dev/null
+++ b/common/serdev.c
@@ -0,0 +1,208 @@
+
+#include <common.h>
+#include <serdev.h>
+
+static void serdev_device_poller(void *context)
+{
+	struct serdev_device *serdev = context;
+	struct console_device *cdev = to_console_device(serdev);
+	unsigned char *buf = serdev->buf;
+	int ret, len;
+
+	/*
+	 * Since this callback is a part of poller infrastructure we
+	 * want to use _non_interruptible version of the function
+	 * below to prevent recursion from happening (regular
+	 * console_drain will call is_timeout, which might end up
+	 * calling this function again).
+	 */
+	len = console_drain_non_interruptible(cdev, serdev->fifo, buf,
+					      PAGE_SIZE,
+					      serdev->polling_window);
+	while (len > 0) {
+		ret = serdev->receive_buf(serdev, buf, len);
+		len -= ret;
+		buf += ret;
+	}
+
+	if (serdev->polling_interval) {
+		/*
+		 * Re-schedule ourselves in 'serdev->polling_interval'
+		 * nanoseconds
+		 */
+		poller_call_async(&serdev->poller,
+				  serdev->polling_interval,
+				  serdev_device_poller,
+				  serdev);
+	} else {
+		poller_async_cancel(&serdev->poller);
+	}
+}
+
+static int serdev_device_set_polling_interval(struct param_d *param, void *serdev)
+{
+	/*
+	 * We execute poller ever time polling_interval changes to get
+	 * any unprocessed immediate Rx data as well as to propagate
+	 * polling_interval chagnes to outstanging async pollers.
+	 */
+	serdev_device_poller(serdev);
+	return 0;
+}
+
+int serdev_device_open(struct serdev_device *serdev)
+{
+	struct console_device *cdev = to_console_device(serdev);
+	struct param_d *p;
+	int ret;
+
+	if (!cdev->putc || !cdev->getc)
+		return -EINVAL;
+
+	if (!serdev->polling_window)
+		return -EINVAL;
+
+	serdev->buf = xzalloc(PAGE_SIZE);
+	serdev->fifo = kfifo_alloc(PAGE_SIZE);
+	if (!serdev->fifo)
+		return -ENOMEM;
+
+	ret = poller_async_register(&serdev->poller);
+	if (ret)
+		return ret;
+
+	ret = console_open(cdev);
+	if (ret)
+		return ret;
+
+	p = dev_add_param_uint64(serdev->dev, "polling_interval",
+				 serdev_device_set_polling_interval, NULL,
+				 &serdev->polling_interval, "%llu", serdev);
+	if (IS_ERR(p))
+		return PTR_ERR(p);
+
+	return 0;
+}
+
+unsigned int serdev_device_set_baudrate(struct serdev_device *serdev,
+					unsigned int speed)
+{
+	struct console_device *cdev = to_console_device(serdev);
+
+	if (console_set_baudrate(cdev, speed) < 0)
+		return 0;
+
+	return console_get_baudrate(cdev);
+}
+
+int serdev_device_write(struct serdev_device *serdev, const unsigned char *buf,
+			size_t count, unsigned long timeout)
+{
+	struct console_device *cdev = to_console_device(serdev);
+
+	while (count--)
+		cdev->putc(cdev, *buf++);
+	/*
+	 * Poll Rx once right after we just send some data in case our
+	 * serdev device implements command/response type of a
+	 * protocol and we need to start draining input as soon as
+	 * possible.
+	 */
+	serdev_device_poller(serdev);
+	return 0;
+}
+
+/*
+ * NOTE: Code below is given primarily as an example of serdev API
+ * usage. It may or may not be as useful or work as well as the
+ * functions above.
+ */
+
+struct serdev_device_reader {
+	unsigned char *buf;
+	size_t len;
+	size_t capacity;
+};
+
+static int serdev_device_reader_receive_buf(struct serdev_device *serdev,
+					    const unsigned char *buf,
+					    size_t size)
+{
+	struct device_d *dev = serdev->dev;
+	struct serdev_device_reader *r = dev->priv;
+	const size_t room = min(r->capacity - r->len, size);
+
+	memcpy(r->buf + r->len, buf, room);
+	r->len += room;
+	/*
+	 * It's important we return 'size' even if we didn't trully
+	 * consume all of the data, since otherwise serdev will keep
+	 * re-executing us until we do. Given the logic above that
+	 * would mean infinite loop.
+	 */
+	return size;
+}
+
+/**
+ * serdev_device_reader_open - Open a reader serdev device
+ *
+ * @serdev:	Underlying serdev device
+ * @capacity:	Storage capacity of the reader
+ *
+ * This function is inteded for creating of reader serdev devices that
+ * can be used in conjunction with serdev_device_read() to perform
+ * trivial fixed length reads from a serdev device.
+ */
+int serdev_device_reader_open(struct serdev_device *serdev, size_t capacity)
+{
+	struct serdev_device_reader *r;
+
+	if (serdev->receive_buf)
+		return -EINVAL;
+
+	r = xzalloc(sizeof(*r));
+	r->capacity = capacity;
+	r->buf = xzalloc(capacity);
+
+	serdev->receive_buf = serdev_device_reader_receive_buf;
+	serdev->dev->priv   = r;
+
+	return 0;
+}
+
+/**
+ * serdev_device_read - Read data from serdev device
+ *
+ * @serdev:	Serdev device to read from (must be a serdev reader)
+ * @buf:	Buffer to read data into
+ * @count:	Number of bytes to read
+ * @timeout:	Read operation timeout
+ *
+ */
+int serdev_device_read(struct serdev_device *serdev, unsigned char *buf,
+		       size_t count, unsigned long timeout)
+{
+	struct device_d *dev = serdev->dev;
+	struct serdev_device_reader *r = dev->priv;
+	int ret;
+
+	uint64_t start = get_time_ns();
+
+	if (serdev->receive_buf != serdev_device_reader_receive_buf)
+		return -EINVAL;
+
+	/*
+	 * is_timeout will implicitly poll serdev via poller
+	 * infrastructure
+	 */
+	while (r->len < count) {
+		if (is_timeout(start, timeout))
+			return -ETIMEDOUT;
+	}
+
+	memcpy(buf, r->buf, count);
+	ret = (r->len == count) ? 0 : -EMSGSIZE;
+	r->len = 0;
+
+	return ret;
+}