summaryrefslogtreecommitdiff
path: root/drivers/platform/surface/aggregator/ssh_packet_layer.h
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/platform/surface/aggregator/ssh_packet_layer.h')
-rw-r--r--drivers/platform/surface/aggregator/ssh_packet_layer.h190
1 files changed, 190 insertions, 0 deletions
diff --git a/drivers/platform/surface/aggregator/ssh_packet_layer.h b/drivers/platform/surface/aggregator/ssh_packet_layer.h
new file mode 100644
index 000000000000..e8757d03f279
--- /dev/null
+++ b/drivers/platform/surface/aggregator/ssh_packet_layer.h
@@ -0,0 +1,190 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * SSH packet transport layer.
+ *
+ * Copyright (C) 2019-2020 Maximilian Luz <luzmaximilian@gmail.com>
+ */
+
+#ifndef _SURFACE_AGGREGATOR_SSH_PACKET_LAYER_H
+#define _SURFACE_AGGREGATOR_SSH_PACKET_LAYER_H
+
+#include <linux/atomic.h>
+#include <linux/kfifo.h>
+#include <linux/ktime.h>
+#include <linux/list.h>
+#include <linux/serdev.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+
+#include <linux/surface_aggregator/serial_hub.h>
+#include "ssh_parser.h"
+
+/**
+ * enum ssh_ptl_state_flags - State-flags for &struct ssh_ptl.
+ *
+ * @SSH_PTL_SF_SHUTDOWN_BIT:
+ * Indicates that the packet transport layer has been shut down or is
+ * being shut down and should not accept any new packets/data.
+ */
+enum ssh_ptl_state_flags {
+ SSH_PTL_SF_SHUTDOWN_BIT,
+};
+
+/**
+ * struct ssh_ptl_ops - Callback operations for packet transport layer.
+ * @data_received: Function called when a data-packet has been received. Both,
+ * the packet layer on which the packet has been received and
+ * the packet's payload data are provided to this function.
+ */
+struct ssh_ptl_ops {
+ void (*data_received)(struct ssh_ptl *p, const struct ssam_span *data);
+};
+
+/**
+ * struct ssh_ptl - SSH packet transport layer.
+ * @serdev: Serial device providing the underlying data transport.
+ * @state: State(-flags) of the transport layer.
+ * @queue: Packet submission queue.
+ * @queue.lock: Lock for modifying the packet submission queue.
+ * @queue.head: List-head of the packet submission queue.
+ * @pending: Set/list of pending packets.
+ * @pending.lock: Lock for modifying the pending set.
+ * @pending.head: List-head of the pending set/list.
+ * @pending.count: Number of currently pending packets.
+ * @tx: Transmitter subsystem.
+ * @tx.running: Flag indicating (desired) transmitter thread state.
+ * @tx.thread: Transmitter thread.
+ * @tx.thread_cplt_tx: Completion for transmitter thread waiting on transfer.
+ * @tx.thread_cplt_pkt: Completion for transmitter thread waiting on packets.
+ * @tx.packet_wq: Waitqueue-head for packet transmit completion.
+ * @rx: Receiver subsystem.
+ * @rx.thread: Receiver thread.
+ * @rx.wq: Waitqueue-head for receiver thread.
+ * @rx.fifo: Buffer for receiving data/pushing data to receiver thread.
+ * @rx.buf: Buffer for evaluating data on receiver thread.
+ * @rx.blocked: List of recent/blocked sequence IDs to detect retransmission.
+ * @rx.blocked.seqs: Array of blocked sequence IDs.
+ * @rx.blocked.offset: Offset indicating where a new ID should be inserted.
+ * @rtx_timeout: Retransmission timeout subsystem.
+ * @rtx_timeout.lock: Lock for modifying the retransmission timeout reaper.
+ * @rtx_timeout.timeout: Timeout interval for retransmission.
+ * @rtx_timeout.expires: Time specifying when the reaper work is next scheduled.
+ * @rtx_timeout.reaper: Work performing timeout checks and subsequent actions.
+ * @ops: Packet layer operations.
+ */
+struct ssh_ptl {
+ struct serdev_device *serdev;
+ unsigned long state;
+
+ struct {
+ spinlock_t lock;
+ struct list_head head;
+ } queue;
+
+ struct {
+ spinlock_t lock;
+ struct list_head head;
+ atomic_t count;
+ } pending;
+
+ struct {
+ atomic_t running;
+ struct task_struct *thread;
+ struct completion thread_cplt_tx;
+ struct completion thread_cplt_pkt;
+ struct wait_queue_head packet_wq;
+ } tx;
+
+ struct {
+ struct task_struct *thread;
+ struct wait_queue_head wq;
+ struct kfifo fifo;
+ struct sshp_buf buf;
+
+ struct {
+ u16 seqs[8];
+ u16 offset;
+ } blocked;
+ } rx;
+
+ struct {
+ spinlock_t lock;
+ ktime_t timeout;
+ ktime_t expires;
+ struct delayed_work reaper;
+ } rtx_timeout;
+
+ struct ssh_ptl_ops ops;
+};
+
+#define __ssam_prcond(func, p, fmt, ...) \
+ do { \
+ typeof(p) __p = (p); \
+ \
+ if (__p) \
+ func(__p, fmt, ##__VA_ARGS__); \
+ } while (0)
+
+#define ptl_dbg(p, fmt, ...) dev_dbg(&(p)->serdev->dev, fmt, ##__VA_ARGS__)
+#define ptl_info(p, fmt, ...) dev_info(&(p)->serdev->dev, fmt, ##__VA_ARGS__)
+#define ptl_warn(p, fmt, ...) dev_warn(&(p)->serdev->dev, fmt, ##__VA_ARGS__)
+#define ptl_err(p, fmt, ...) dev_err(&(p)->serdev->dev, fmt, ##__VA_ARGS__)
+#define ptl_dbg_cond(p, fmt, ...) __ssam_prcond(ptl_dbg, p, fmt, ##__VA_ARGS__)
+
+#define to_ssh_ptl(ptr, member) \
+ container_of(ptr, struct ssh_ptl, member)
+
+int ssh_ptl_init(struct ssh_ptl *ptl, struct serdev_device *serdev,
+ struct ssh_ptl_ops *ops);
+
+void ssh_ptl_destroy(struct ssh_ptl *ptl);
+
+/**
+ * ssh_ptl_get_device() - Get device associated with packet transport layer.
+ * @ptl: The packet transport layer.
+ *
+ * Return: Returns the device on which the given packet transport layer builds
+ * upon.
+ */
+static inline struct device *ssh_ptl_get_device(struct ssh_ptl *ptl)
+{
+ return ptl->serdev ? &ptl->serdev->dev : NULL;
+}
+
+int ssh_ptl_tx_start(struct ssh_ptl *ptl);
+int ssh_ptl_tx_stop(struct ssh_ptl *ptl);
+int ssh_ptl_rx_start(struct ssh_ptl *ptl);
+int ssh_ptl_rx_stop(struct ssh_ptl *ptl);
+void ssh_ptl_shutdown(struct ssh_ptl *ptl);
+
+int ssh_ptl_submit(struct ssh_ptl *ptl, struct ssh_packet *p);
+void ssh_ptl_cancel(struct ssh_packet *p);
+
+int ssh_ptl_rx_rcvbuf(struct ssh_ptl *ptl, const u8 *buf, size_t n);
+
+/**
+ * ssh_ptl_tx_wakeup_transfer() - Wake up packet transmitter thread for
+ * transfer.
+ * @ptl: The packet transport layer.
+ *
+ * Wakes up the packet transmitter thread, notifying it that the underlying
+ * transport has more space for data to be transmitted. If the packet
+ * transport layer has been shut down, calls to this function will be ignored.
+ */
+static inline void ssh_ptl_tx_wakeup_transfer(struct ssh_ptl *ptl)
+{
+ if (test_bit(SSH_PTL_SF_SHUTDOWN_BIT, &ptl->state))
+ return;
+
+ complete(&ptl->tx.thread_cplt_tx);
+}
+
+void ssh_packet_init(struct ssh_packet *packet, unsigned long type,
+ u8 priority, const struct ssh_packet_ops *ops);
+
+int ssh_ctrl_packet_cache_init(void);
+void ssh_ctrl_packet_cache_destroy(void);
+
+#endif /* _SURFACE_AGGREGATOR_SSH_PACKET_LAYER_H */