Merge branch 'master' of git://git.denx.de/u-boot-tegra

1 files changed, 179 insertions, 0 deletions

diff --git a/arch/arm/include/asm/arch-tegra/ivc.h b/arch/arm/include/asm/arch-tegra/ivc.h
new file mode 100644
index 0000000000..7f2287ae28
--- /dev/null
+++ b/arch/arm/include/asm/arch-tegra/ivc.h
@@ -0,0 +1,179 @@
+/*
+ * Copyright (c) 2016, NVIDIA CORPORATION.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#ifndef _ASM_ARCH_TEGRA_IVC_H
+#define _ASM_ARCH_TEGRA_IVC_H
+
+#include <common.h>
+
+/*
+ * Tegra IVC is a communication protocol that transfers fixed-size frames
+ * bi-directionally and in-order between the local CPU and some remote entity.
+ * Communication is via a statically sized and allocated buffer in shared
+ * memory and a notification mechanism.
+ *
+ * This API handles all aspects of the shared memory buffer's metadata, and
+ * leaves all aspects of the frame content to the calling code; frames
+ * typically contain some higher-level protocol. The notification mechanism is
+ * also handled externally to this API, since it can vary from instance to
+ * instance.
+ *
+ * The client model is to first find some free (for TX) or filled (for RX)
+ * frame, process that frame's memory buffer (fill or read it), and then
+ * inform the protocol that the frame has been filled/read, i.e. advance the
+ * write/read pointer. If the channel is full, there may be no available frames
+ * to fill/read. In this case, client code may either poll for an available
+ * frame, or wait for the remote entity to send a notification to the local
+ * CPU.
+ */
+
+/**
+ * struct tegra_ivc - In-memory shared memory layout.
+ *
+ * This is described in detail in ivc.c.
+ */
+struct tegra_ivc_channel_header;
+
+/**
+ * struct tegra_ivc - Software state of an IVC channel.
+ *
+ * This state is internal to the IVC code and should not be accessed directly
+ * by clients. It is public solely so clients can allocate storage for the
+ * structure.
+ */
+struct tegra_ivc {
+	/**
+	 * rx_channel - Pointer to the shared memory region used to receive
+	 * messages from the remote entity.
+	 */
+	struct tegra_ivc_channel_header *rx_channel;
+	/**
+	 * tx_channel - Pointer to the shared memory region used to send
+	 * messages to the remote entity.
+	 */
+	struct tegra_ivc_channel_header *tx_channel;
+	/**
+	 * r_pos - The position in list of frames in rx_channel that we are
+	 * reading from.
+	 */
+	uint32_t r_pos;
+	/**
+	 * w_pos - The position in list of frames in tx_channel that we are
+	 * writing to.
+	 */
+	uint32_t w_pos;
+	/**
+	 * nframes - The number of frames allocated (in each direction) in
+	 * shared memory.
+	 */
+	uint32_t nframes;
+	/**
+	 * frame_size - The size of each frame in shared memory.
+	 */
+	uint32_t frame_size;
+	/**
+	 * notify - Function to call to notify the remote processor of a
+	 * change in channel state.
+	 */
+	void (*notify)(struct tegra_ivc *);
+};
+
+/**
+ * tegra_ivc_read_get_next_frame - Locate the next frame to receive.
+ *
+ * Locate the next frame to be received/processed, return the address of the
+ * frame, and do not remove it from the queue. Repeated calls to this function
+ * will return the same address until tegra_ivc_read_advance() is called.
+ *
+ * @ivc		The IVC channel.
+ * @frame	Pointer to be filled with the address of the frame to receive.
+ *
+ * @return 0 if a frame is available, else a negative error code.
+ */
+int tegra_ivc_read_get_next_frame(struct tegra_ivc *ivc, void **frame);
+
+/**
+ * tegra_ivc_read_advance - Advance the read queue.
+ *
+ * Inform the protocol and remote entity that the frame returned by
+ * tegra_ivc_read_get_next_frame() has been processed. The remote end may then
+ * re-use it to transmit further data. Subsequent to this function returning,
+ * tegra_ivc_read_get_next_frame() will return a different frame.
+ *
+ * @ivc		The IVC channel.
+ *
+ * @return 0 if OK, else a negative error code.
+ */
+int tegra_ivc_read_advance(struct tegra_ivc *ivc);
+
+/**
+ * tegra_ivc_write_get_next_frame - Locate the next frame to fill for transmit.
+ *
+ * Locate the next frame to be filled for transmit, return the address of the
+ * frame, and do not add it to the queue. Repeated calls to this function
+ * will return the same address until tegra_ivc_read_advance() is called.
+ *
+ * @ivc		The IVC channel.
+ * @frame	Pointer to be filled with the address of the frame to fill.
+ *
+ * @return 0 if a frame is available, else a negative error code.
+ */
+int tegra_ivc_write_get_next_frame(struct tegra_ivc *ivc, void **frame);
+
+/**
+ * tegra_ivc_write_advance - Advance the write queue.
+ *
+ * Inform the protocol and remote entity that the frame returned by
+ * tegra_ivc_write_get_next_frame() has been filled and should be transmitted.
+ * The remote end may then read data from it. Subsequent to this function
+ * returning, tegra_ivc_write_get_next_frame() will return a different frame.
+ *
+ * @ivc		The IVC channel.
+ *
+ * @return 0 if OK, else a negative error code.
+ */
+int tegra_ivc_write_advance(struct tegra_ivc *ivc);
+
+/**
+ * tegra_ivc_channel_notified - handle internal messages
+ *
+ * This function must be called following every notification.
+ *
+ * @ivc		The IVC channel.
+ *
+ * @return 0 if the channel is ready for communication, or -EAGAIN if a
+ * channel reset is in progress.
+ */
+int tegra_ivc_channel_notified(struct tegra_ivc *ivc);
+
+/**
+ * tegra_ivc_channel_reset - initiates a reset of the shared memory state
+ *
+ * This function must be called after a channel is initialized but before it
+ * is used for communication. The channel will be ready for use when a
+ * subsequent call to notify the remote of the channel reset indicates the
+ * reset operation is complete.
+ *
+ * @ivc		The IVC channel.
+ */
+void tegra_ivc_channel_reset(struct tegra_ivc *ivc);
+
+/**
+ * tegra_ivc_init - Initialize a channel's software state.
+ *
+ * @ivc		The IVC channel.
+ * @rx_base	Address of the the RX shared memory buffer.
+ * @tx_base	Address of the the TX shared memory buffer.
+ * @nframes	Number of frames in each shared memory buffer.
+ * @frame_size	Size of each frame.
+ *
+ * @return 0 if OK, else a negative error code.
+ */
+int tegra_ivc_init(struct tegra_ivc *ivc, ulong rx_base, ulong tx_base,
+		   uint32_t nframes, uint32_t frame_size,
+		   void (*notify)(struct tegra_ivc *));
+
+#endif