Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 687 insertions, 0 deletions

diff --git a/drivers/firmware/tegra/ivc.c b/drivers/firmware/tegra/ivc.c
new file mode 100644
index 000000000..e2398cd7c
--- /dev/null
+++ b/drivers/firmware/tegra/ivc.c
@@ -0,0 +1,687 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2014-2016, NVIDIA CORPORATION.  All rights reserved.
+ */
+
+#include <soc/tegra/ivc.h>
+
+#define TEGRA_IVC_ALIGN 64
+
+/*
+ * IVC channel reset protocol.
+ *
+ * Each end uses its tx_channel.state to indicate its synchronization state.
+ */
+enum tegra_ivc_state {
+	/*
+	 * This value is zero for backwards compatibility with services that
+	 * assume channels to be initially zeroed. Such channels are in an
+	 * initially valid state, but cannot be asynchronously reset, and must
+	 * maintain a valid state at all times.
+	 *
+	 * The transmitting end can enter the established state from the sync or
+	 * ack state when it observes the receiving endpoint in the ack or
+	 * established state, indicating that has cleared the counters in our
+	 * rx_channel.
+	 */
+	TEGRA_IVC_STATE_ESTABLISHED = 0,
+
+	/*
+	 * If an endpoint is observed in the sync state, the remote endpoint is
+	 * allowed to clear the counters it owns asynchronously with respect to
+	 * the current endpoint. Therefore, the current endpoint is no longer
+	 * allowed to communicate.
+	 */
+	TEGRA_IVC_STATE_SYNC,
+
+	/*
+	 * When the transmitting end observes the receiving end in the sync
+	 * state, it can clear the w_count and r_count and transition to the ack
+	 * state. If the remote endpoint observes us in the ack state, it can
+	 * return to the established state once it has cleared its counters.
+	 */
+	TEGRA_IVC_STATE_ACK
+};
+
+/*
+ * This structure is divided into two-cache aligned parts, the first is only
+ * written through the tx.channel pointer, while the second is only written
+ * through the rx.channel pointer. This delineates ownership of the cache
+ * lines, which is critical to performance and necessary in non-cache coherent
+ * implementations.
+ */
+struct tegra_ivc_header {
+	union {
+		struct {
+			/* fields owned by the transmitting end */
+			u32 count;
+			u32 state;
+		};
+
+		u8 pad[TEGRA_IVC_ALIGN];
+	} tx;
+
+	union {
+		/* fields owned by the receiving end */
+		u32 count;
+		u8 pad[TEGRA_IVC_ALIGN];
+	} rx;
+};
+
+static inline void tegra_ivc_invalidate(struct tegra_ivc *ivc, dma_addr_t phys)
+{
+	if (!ivc->peer)
+		return;
+
+	dma_sync_single_for_cpu(ivc->peer, phys, TEGRA_IVC_ALIGN,
+				DMA_FROM_DEVICE);
+}
+
+static inline void tegra_ivc_flush(struct tegra_ivc *ivc, dma_addr_t phys)
+{
+	if (!ivc->peer)
+		return;
+
+	dma_sync_single_for_device(ivc->peer, phys, TEGRA_IVC_ALIGN,
+				   DMA_TO_DEVICE);
+}
+
+static inline bool tegra_ivc_empty(struct tegra_ivc *ivc,
+				   struct tegra_ivc_header *header)
+{
+	/*
+	 * This function performs multiple checks on the same values with
+	 * security implications, so create snapshots with READ_ONCE() to
+	 * ensure that these checks use the same values.
+	 */
+	u32 tx = READ_ONCE(header->tx.count);
+	u32 rx = READ_ONCE(header->rx.count);
+
+	/*
+	 * Perform an over-full check to prevent denial of service attacks
+	 * where a server could be easily fooled into believing that there's
+	 * an extremely large number of frames ready, since receivers are not
+	 * expected to check for full or over-full conditions.
+	 *
+	 * Although the channel isn't empty, this is an invalid case caused by
+	 * a potentially malicious peer, so returning empty is safer, because
+	 * it gives the impression that the channel has gone silent.
+	 */
+	if (tx - rx > ivc->num_frames)
+		return true;
+
+	return tx == rx;
+}
+
+static inline bool tegra_ivc_full(struct tegra_ivc *ivc,
+				  struct tegra_ivc_header *header)
+{
+	u32 tx = READ_ONCE(header->tx.count);
+	u32 rx = READ_ONCE(header->rx.count);
+
+	/*
+	 * Invalid cases where the counters indicate that the queue is over
+	 * capacity also appear full.
+	 */
+	return tx - rx >= ivc->num_frames;
+}
+
+static inline u32 tegra_ivc_available(struct tegra_ivc *ivc,
+				      struct tegra_ivc_header *header)
+{
+	u32 tx = READ_ONCE(header->tx.count);
+	u32 rx = READ_ONCE(header->rx.count);
+
+	/*
+	 * This function isn't expected to be used in scenarios where an
+	 * over-full situation can lead to denial of service attacks. See the
+	 * comment in tegra_ivc_empty() for an explanation about special
+	 * over-full considerations.
+	 */
+	return tx - rx;
+}
+
+static inline void tegra_ivc_advance_tx(struct tegra_ivc *ivc)
+{
+	WRITE_ONCE(ivc->tx.channel->tx.count,
+		   READ_ONCE(ivc->tx.channel->tx.count) + 1);
+
+	if (ivc->tx.position == ivc->num_frames - 1)
+		ivc->tx.position = 0;
+	else
+		ivc->tx.position++;
+}
+
+static inline void tegra_ivc_advance_rx(struct tegra_ivc *ivc)
+{
+	WRITE_ONCE(ivc->rx.channel->rx.count,
+		   READ_ONCE(ivc->rx.channel->rx.count) + 1);
+
+	if (ivc->rx.position == ivc->num_frames - 1)
+		ivc->rx.position = 0;
+	else
+		ivc->rx.position++;
+}
+
+static inline int tegra_ivc_check_read(struct tegra_ivc *ivc)
+{
+	unsigned int offset = offsetof(struct tegra_ivc_header, tx.count);
+
+	/*
+	 * tx.channel->state is set locally, so it is not synchronized with
+	 * state from the remote peer. The remote peer cannot reset its
+	 * transmit counters until we've acknowledged its synchronization
+	 * request, so no additional synchronization is required because an
+	 * asynchronous transition of rx.channel->state to
+	 * TEGRA_IVC_STATE_ACK is not allowed.
+	 */
+	if (ivc->tx.channel->tx.state != TEGRA_IVC_STATE_ESTABLISHED)
+		return -ECONNRESET;
+
+	/*
+	 * Avoid unnecessary invalidations when performing repeated accesses
+	 * to an IVC channel by checking the old queue pointers first.
+	 *
+	 * Synchronization is only necessary when these pointers indicate
+	 * empty or full.
+	 */
+	if (!tegra_ivc_empty(ivc, ivc->rx.channel))
+		return 0;
+
+	tegra_ivc_invalidate(ivc, ivc->rx.phys + offset);
+
+	if (tegra_ivc_empty(ivc, ivc->rx.channel))
+		return -ENOSPC;
+
+	return 0;
+}
+
+static inline int tegra_ivc_check_write(struct tegra_ivc *ivc)
+{
+	unsigned int offset = offsetof(struct tegra_ivc_header, rx.count);
+
+	if (ivc->tx.channel->tx.state != TEGRA_IVC_STATE_ESTABLISHED)
+		return -ECONNRESET;
+
+	if (!tegra_ivc_full(ivc, ivc->tx.channel))
+		return 0;
+
+	tegra_ivc_invalidate(ivc, ivc->tx.phys + offset);
+
+	if (tegra_ivc_full(ivc, ivc->tx.channel))
+		return -ENOSPC;
+
+	return 0;
+}
+
+static void *tegra_ivc_frame_virt(struct tegra_ivc *ivc,
+				  struct tegra_ivc_header *header,
+				  unsigned int frame)
+{
+	if (WARN_ON(frame >= ivc->num_frames))
+		return ERR_PTR(-EINVAL);
+
+	return (void *)(header + 1) + ivc->frame_size * frame;
+}
+
+static inline dma_addr_t tegra_ivc_frame_phys(struct tegra_ivc *ivc,
+					      dma_addr_t phys,
+					      unsigned int frame)
+{
+	unsigned long offset;
+
+	offset = sizeof(struct tegra_ivc_header) + ivc->frame_size * frame;
+
+	return phys + offset;
+}
+
+static inline void tegra_ivc_invalidate_frame(struct tegra_ivc *ivc,
+					      dma_addr_t phys,
+					      unsigned int frame,
+					      unsigned int offset,
+					      size_t size)
+{
+	if (!ivc->peer || WARN_ON(frame >= ivc->num_frames))
+		return;
+
+	phys = tegra_ivc_frame_phys(ivc, phys, frame) + offset;
+
+	dma_sync_single_for_cpu(ivc->peer, phys, size, DMA_FROM_DEVICE);
+}
+
+static inline void tegra_ivc_flush_frame(struct tegra_ivc *ivc,
+					 dma_addr_t phys,
+					 unsigned int frame,
+					 unsigned int offset,
+					 size_t size)
+{
+	if (!ivc->peer || WARN_ON(frame >= ivc->num_frames))
+		return;
+
+	phys = tegra_ivc_frame_phys(ivc, phys, frame) + offset;
+
+	dma_sync_single_for_device(ivc->peer, phys, size, DMA_TO_DEVICE);
+}
+
+/* directly peek at the next frame rx'ed */
+void *tegra_ivc_read_get_next_frame(struct tegra_ivc *ivc)
+{
+	int err;
+
+	if (WARN_ON(ivc == NULL))
+		return ERR_PTR(-EINVAL);
+
+	err = tegra_ivc_check_read(ivc);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	/*
+	 * Order observation of ivc->rx.position potentially indicating new
+	 * data before data read.
+	 */
+	smp_rmb();
+
+	tegra_ivc_invalidate_frame(ivc, ivc->rx.phys, ivc->rx.position, 0,
+				   ivc->frame_size);
+
+	return tegra_ivc_frame_virt(ivc, ivc->rx.channel, ivc->rx.position);
+}
+EXPORT_SYMBOL(tegra_ivc_read_get_next_frame);
+
+int tegra_ivc_read_advance(struct tegra_ivc *ivc)
+{
+	unsigned int rx = offsetof(struct tegra_ivc_header, rx.count);
+	unsigned int tx = offsetof(struct tegra_ivc_header, tx.count);
+	int err;
+
+	/*
+	 * No read barriers or synchronization here: the caller is expected to
+	 * have already observed the channel non-empty. This check is just to
+	 * catch programming errors.
+	 */
+	err = tegra_ivc_check_read(ivc);
+	if (err < 0)
+		return err;
+
+	tegra_ivc_advance_rx(ivc);
+
+	tegra_ivc_flush(ivc, ivc->rx.phys + rx);
+
+	/*
+	 * Ensure our write to ivc->rx.position occurs before our read from
+	 * ivc->tx.position.
+	 */
+	smp_mb();
+
+	/*
+	 * Notify only upon transition from full to non-full. The available
+	 * count can only asynchronously increase, so the worst possible
+	 * side-effect will be a spurious notification.
+	 */
+	tegra_ivc_invalidate(ivc, ivc->rx.phys + tx);
+
+	if (tegra_ivc_available(ivc, ivc->rx.channel) == ivc->num_frames - 1)
+		ivc->notify(ivc, ivc->notify_data);
+
+	return 0;
+}
+EXPORT_SYMBOL(tegra_ivc_read_advance);
+
+/* directly poke at the next frame to be tx'ed */
+void *tegra_ivc_write_get_next_frame(struct tegra_ivc *ivc)
+{
+	int err;
+
+	err = tegra_ivc_check_write(ivc);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	return tegra_ivc_frame_virt(ivc, ivc->tx.channel, ivc->tx.position);
+}
+EXPORT_SYMBOL(tegra_ivc_write_get_next_frame);
+
+/* advance the tx buffer */
+int tegra_ivc_write_advance(struct tegra_ivc *ivc)
+{
+	unsigned int tx = offsetof(struct tegra_ivc_header, tx.count);
+	unsigned int rx = offsetof(struct tegra_ivc_header, rx.count);
+	int err;
+
+	err = tegra_ivc_check_write(ivc);
+	if (err < 0)
+		return err;
+
+	tegra_ivc_flush_frame(ivc, ivc->tx.phys, ivc->tx.position, 0,
+			      ivc->frame_size);
+
+	/*
+	 * Order any possible stores to the frame before update of
+	 * ivc->tx.position.
+	 */
+	smp_wmb();
+
+	tegra_ivc_advance_tx(ivc);
+	tegra_ivc_flush(ivc, ivc->tx.phys + tx);
+
+	/*
+	 * Ensure our write to ivc->tx.position occurs before our read from
+	 * ivc->rx.position.
+	 */
+	smp_mb();
+
+	/*
+	 * Notify only upon transition from empty to non-empty. The available
+	 * count can only asynchronously decrease, so the worst possible
+	 * side-effect will be a spurious notification.
+	 */
+	tegra_ivc_invalidate(ivc, ivc->tx.phys + rx);
+
+	if (tegra_ivc_available(ivc, ivc->tx.channel) == 1)
+		ivc->notify(ivc, ivc->notify_data);
+
+	return 0;
+}
+EXPORT_SYMBOL(tegra_ivc_write_advance);
+
+void tegra_ivc_reset(struct tegra_ivc *ivc)
+{
+	unsigned int offset = offsetof(struct tegra_ivc_header, tx.count);
+
+	ivc->tx.channel->tx.state = TEGRA_IVC_STATE_SYNC;
+	tegra_ivc_flush(ivc, ivc->tx.phys + offset);
+	ivc->notify(ivc, ivc->notify_data);
+}
+EXPORT_SYMBOL(tegra_ivc_reset);
+
+/*
+ * =======================================================
+ *  IVC State Transition Table - see tegra_ivc_notified()
+ * =======================================================
+ *
+ *	local	remote	action
+ *	-----	------	-----------------------------------
+ *	SYNC	EST	<none>
+ *	SYNC	ACK	reset counters; move to EST; notify
+ *	SYNC	SYNC	reset counters; move to ACK; notify
+ *	ACK	EST	move to EST; notify
+ *	ACK	ACK	move to EST; notify
+ *	ACK	SYNC	reset counters; move to ACK; notify
+ *	EST	EST	<none>
+ *	EST	ACK	<none>
+ *	EST	SYNC	reset counters; move to ACK; notify
+ *
+ * ===============================================================
+ */
+
+int tegra_ivc_notified(struct tegra_ivc *ivc)
+{
+	unsigned int offset = offsetof(struct tegra_ivc_header, tx.count);
+	enum tegra_ivc_state state;
+
+	/* Copy the receiver's state out of shared memory. */
+	tegra_ivc_invalidate(ivc, ivc->rx.phys + offset);
+	state = READ_ONCE(ivc->rx.channel->tx.state);
+
+	if (state == TEGRA_IVC_STATE_SYNC) {
+		offset = offsetof(struct tegra_ivc_header, tx.count);
+
+		/*
+		 * Order observation of TEGRA_IVC_STATE_SYNC before stores
+		 * clearing tx.channel.
+		 */
+		smp_rmb();
+
+		/*
+		 * Reset tx.channel counters. The remote end is in the SYNC
+		 * state and won't make progress until we change our state,
+		 * so the counters are not in use at this time.
+		 */
+		ivc->tx.channel->tx.count = 0;
+		ivc->rx.channel->rx.count = 0;
+
+		ivc->tx.position = 0;
+		ivc->rx.position = 0;
+
+		/*
+		 * Ensure that counters appear cleared before new state can be
+		 * observed.
+		 */
+		smp_wmb();
+
+		/*
+		 * Move to ACK state. We have just cleared our counters, so it
+		 * is now safe for the remote end to start using these values.
+		 */
+		ivc->tx.channel->tx.state = TEGRA_IVC_STATE_ACK;
+		tegra_ivc_flush(ivc, ivc->tx.phys + offset);
+
+		/*
+		 * Notify remote end to observe state transition.
+		 */
+		ivc->notify(ivc, ivc->notify_data);
+
+	} else if (ivc->tx.channel->tx.state == TEGRA_IVC_STATE_SYNC &&
+		   state == TEGRA_IVC_STATE_ACK) {
+		offset = offsetof(struct tegra_ivc_header, tx.count);
+
+		/*
+		 * Order observation of ivc_state_sync before stores clearing
+		 * tx_channel.
+		 */
+		smp_rmb();
+
+		/*
+		 * Reset tx.channel counters. The remote end is in the ACK
+		 * state and won't make progress until we change our state,
+		 * so the counters are not in use at this time.
+		 */
+		ivc->tx.channel->tx.count = 0;
+		ivc->rx.channel->rx.count = 0;
+
+		ivc->tx.position = 0;
+		ivc->rx.position = 0;
+
+		/*
+		 * Ensure that counters appear cleared before new state can be
+		 * observed.
+		 */
+		smp_wmb();
+
+		/*
+		 * Move to ESTABLISHED state. We know that the remote end has
+		 * already cleared its counters, so it is safe to start
+		 * writing/reading on this channel.
+		 */
+		ivc->tx.channel->tx.state = TEGRA_IVC_STATE_ESTABLISHED;
+		tegra_ivc_flush(ivc, ivc->tx.phys + offset);
+
+		/*
+		 * Notify remote end to observe state transition.
+		 */
+		ivc->notify(ivc, ivc->notify_data);
+
+	} else if (ivc->tx.channel->tx.state == TEGRA_IVC_STATE_ACK) {
+		offset = offsetof(struct tegra_ivc_header, tx.count);
+
+		/*
+		 * At this point, we have observed the peer to be in either
+		 * the ACK or ESTABLISHED state. Next, order observation of
+		 * peer state before storing to tx.channel.
+		 */
+		smp_rmb();
+
+		/*
+		 * Move to ESTABLISHED state. We know that we have previously
+		 * cleared our counters, and we know that the remote end has
+		 * cleared its counters, so it is safe to start writing/reading
+		 * on this channel.
+		 */
+		ivc->tx.channel->tx.state = TEGRA_IVC_STATE_ESTABLISHED;
+		tegra_ivc_flush(ivc, ivc->tx.phys + offset);
+
+		/*
+		 * Notify remote end to observe state transition.
+		 */
+		ivc->notify(ivc, ivc->notify_data);
+
+	} else {
+		/*
+		 * There is no need to handle any further action. Either the
+		 * channel is already fully established, or we are waiting for
+		 * the remote end to catch up with our current state. Refer
+		 * to the diagram in "IVC State Transition Table" above.
+		 */
+	}
+
+	if (ivc->tx.channel->tx.state != TEGRA_IVC_STATE_ESTABLISHED)
+		return -EAGAIN;
+
+	return 0;
+}
+EXPORT_SYMBOL(tegra_ivc_notified);
+
+size_t tegra_ivc_align(size_t size)
+{
+	return ALIGN(size, TEGRA_IVC_ALIGN);
+}
+EXPORT_SYMBOL(tegra_ivc_align);
+
+unsigned tegra_ivc_total_queue_size(unsigned queue_size)
+{
+	if (!IS_ALIGNED(queue_size, TEGRA_IVC_ALIGN)) {
+		pr_err("%s: queue_size (%u) must be %u-byte aligned\n",
+		       __func__, queue_size, TEGRA_IVC_ALIGN);
+		return 0;
+	}
+
+	return queue_size + sizeof(struct tegra_ivc_header);
+}
+EXPORT_SYMBOL(tegra_ivc_total_queue_size);
+
+static int tegra_ivc_check_params(unsigned long rx, unsigned long tx,
+				  unsigned int num_frames, size_t frame_size)
+{
+	BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct tegra_ivc_header, tx.count),
+				 TEGRA_IVC_ALIGN));
+	BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct tegra_ivc_header, rx.count),
+				 TEGRA_IVC_ALIGN));
+	BUILD_BUG_ON(!IS_ALIGNED(sizeof(struct tegra_ivc_header),
+				 TEGRA_IVC_ALIGN));
+
+	if ((uint64_t)num_frames * (uint64_t)frame_size >= 0x100000000UL) {
+		pr_err("num_frames * frame_size overflows\n");
+		return -EINVAL;
+	}
+
+	if (!IS_ALIGNED(frame_size, TEGRA_IVC_ALIGN)) {
+		pr_err("frame size not adequately aligned: %zu\n", frame_size);
+		return -EINVAL;
+	}
+
+	/*
+	 * The headers must at least be aligned enough for counters
+	 * to be accessed atomically.
+	 */
+	if (!IS_ALIGNED(rx, TEGRA_IVC_ALIGN)) {
+		pr_err("IVC channel start not aligned: %#lx\n", rx);
+		return -EINVAL;
+	}
+
+	if (!IS_ALIGNED(tx, TEGRA_IVC_ALIGN)) {
+		pr_err("IVC channel start not aligned: %#lx\n", tx);
+		return -EINVAL;
+	}
+
+	if (rx < tx) {
+		if (rx + frame_size * num_frames > tx) {
+			pr_err("queue regions overlap: %#lx + %zx > %#lx\n",
+			       rx, frame_size * num_frames, tx);
+			return -EINVAL;
+		}
+	} else {
+		if (tx + frame_size * num_frames > rx) {
+			pr_err("queue regions overlap: %#lx + %zx > %#lx\n",
+			       tx, frame_size * num_frames, rx);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+int tegra_ivc_init(struct tegra_ivc *ivc, struct device *peer, void *rx,
+		   dma_addr_t rx_phys, void *tx, dma_addr_t tx_phys,
+		   unsigned int num_frames, size_t frame_size,
+		   void (*notify)(struct tegra_ivc *ivc, void *data),
+		   void *data)
+{
+	size_t queue_size;
+	int err;
+
+	if (WARN_ON(!ivc || !notify))
+		return -EINVAL;
+
+	/*
+	 * All sizes that can be returned by communication functions should
+	 * fit in an int.
+	 */
+	if (frame_size > INT_MAX)
+		return -E2BIG;
+
+	err = tegra_ivc_check_params((unsigned long)rx, (unsigned long)tx,
+				     num_frames, frame_size);
+	if (err < 0)
+		return err;
+
+	queue_size = tegra_ivc_total_queue_size(num_frames * frame_size);
+
+	if (peer) {
+		ivc->rx.phys = dma_map_single(peer, rx, queue_size,
+					      DMA_BIDIRECTIONAL);
+		if (dma_mapping_error(peer, ivc->rx.phys))
+			return -ENOMEM;
+
+		ivc->tx.phys = dma_map_single(peer, tx, queue_size,
+					      DMA_BIDIRECTIONAL);
+		if (dma_mapping_error(peer, ivc->tx.phys)) {
+			dma_unmap_single(peer, ivc->rx.phys, queue_size,
+					 DMA_BIDIRECTIONAL);
+			return -ENOMEM;
+		}
+	} else {
+		ivc->rx.phys = rx_phys;
+		ivc->tx.phys = tx_phys;
+	}
+
+	ivc->rx.channel = rx;
+	ivc->tx.channel = tx;
+	ivc->peer = peer;
+	ivc->notify = notify;
+	ivc->notify_data = data;
+	ivc->frame_size = frame_size;
+	ivc->num_frames = num_frames;
+
+	/*
+	 * These values aren't necessarily correct until the channel has been
+	 * reset.
+	 */
+	ivc->tx.position = 0;
+	ivc->rx.position = 0;
+
+	return 0;
+}
+EXPORT_SYMBOL(tegra_ivc_init);
+
+void tegra_ivc_cleanup(struct tegra_ivc *ivc)
+{
+	if (ivc->peer) {
+		size_t size = tegra_ivc_total_queue_size(ivc->num_frames *
+							 ivc->frame_size);
+
+		dma_unmap_single(ivc->peer, ivc->rx.phys, size,
+				 DMA_BIDIRECTIONAL);
+		dma_unmap_single(ivc->peer, ivc->tx.phys, size,
+				 DMA_BIDIRECTIONAL);
+	}
+}
+EXPORT_SYMBOL(tegra_ivc_cleanup);