tty: n_smux: Add SMUX TTY Line Discipline Driver
Add new Serial Multiplexer (SMUX) driver.
This driver multiplexes multiple logical channels over a single
physical HSUART channel using the TTY Line Discipline framework.
This driver will be used in Fusion 4 for control plane, data plane
and DIAG traffic between Application processor and QSC modem.
Change-Id: Ibecf6cea872f5baf11fb93ded6124243a37a2085
Signed-off-by: Eric Holmberg <eholmber@codeaurora.org>
Signed-off-by: Angshuman Sarkar <angshuman@codeaurora.org>
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
diff --git a/include/linux/smux.h b/include/linux/smux.h
new file mode 100644
index 0000000..64d0ed6
--- /dev/null
+++ b/include/linux/smux.h
@@ -0,0 +1,295 @@
+/* include/linux/smux.h
+ *
+ * Copyright (c) 2012, Code Aurora Forum. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+#ifndef SMUX_H
+#define SMUX_H
+
+/**
+ * Logical Channel IDs
+ *
+ * This must be identical between local and remote clients.
+ */
+enum {
+ /* Data Ports */
+ SMUX_DATA_0,
+ SMUX_DATA_1,
+ SMUX_DATA_2,
+ SMUX_DATA_3,
+ SMUX_DATA_4,
+ SMUX_DATA_5,
+ SMUX_DATA_6,
+ SMUX_DATA_7,
+ SMUX_DATA_8,
+ SMUX_DATA_9,
+ SMUX_USB_RMNET_DATA_0,
+ SMUX_USB_DUN_0,
+ SMUX_USB_DIAG_0,
+ SMUX_SYS_MONITOR_0,
+ SMUX_CSVT_0,
+ /* add new data ports here */
+
+ /* Control Ports */
+ SMUX_DATA_CTL_0 = 32,
+ SMUX_DATA_CTL_1,
+ SMUX_DATA_CTL_2,
+ SMUX_DATA_CTL_3,
+ SMUX_DATA_CTL_4,
+ SMUX_DATA_CTL_5,
+ SMUX_DATA_CTL_6,
+ SMUX_DATA_CTL_7,
+ SMUX_DATA_CTL_8,
+ SMUX_DATA_CTL_9,
+ SMUX_USB_RMNET_CTL_0,
+ SMUX_USB_DUN_CTL_0_UNUSED,
+ SMUX_USB_DIAG_CTL_0,
+ SMUX_SYS_MONITOR_CTL_0,
+ SMUX_CSVT_CTL_0,
+ /* add new control ports here */
+
+ SMUX_TEST_LCID,
+ SMUX_NUM_LOGICAL_CHANNELS,
+};
+
+/**
+ * Notification events that are passed to the notify() function.
+ *
+ * If the @metadata argument in the notifier is non-null, then it will
+ * point to the associated struct smux_meta_* structure.
+ */
+enum {
+ SMUX_CONNECTED, /* @metadata is null */
+ SMUX_DISCONNECTED,
+ SMUX_READ_DONE,
+ SMUX_READ_FAIL,
+ SMUX_WRITE_DONE,
+ SMUX_WRITE_FAIL,
+ SMUX_TIOCM_UPDATE,
+ SMUX_LOW_WM_HIT, /* @metadata is NULL */
+ SMUX_HIGH_WM_HIT, /* @metadata is NULL */
+};
+
+/**
+ * Channel options used to modify channel behavior.
+ */
+enum {
+ SMUX_CH_OPTION_LOCAL_LOOPBACK = 1 << 0,
+ SMUX_CH_OPTION_REMOTE_LOOPBACK = 1 << 1,
+ SMUX_CH_OPTION_REMOTE_TX_STOP = 1 << 2,
+};
+
+/**
+ * Metadata for SMUX_DISCONNECTED notification
+ *
+ * @is_ssr: Disconnect caused by subsystem restart
+ */
+struct smux_meta_disconnected {
+ int is_ssr;
+};
+
+/**
+ * Metadata for SMUX_READ_DONE/SMUX_READ_FAIL notification
+ *
+ * @pkt_priv: Packet-specific private data
+ * @buffer: Buffer pointer passed into msm_smux_write
+ * @len: Buffer length passed into msm_smux_write
+ */
+struct smux_meta_read {
+ void *pkt_priv;
+ void *buffer;
+ int len;
+};
+
+/**
+ * Metadata for SMUX_WRITE_DONE/SMUX_WRITE_FAIL notification
+ *
+ * @pkt_priv: Packet-specific private data
+ * @buffer: Buffer pointer returned by get_rx_buffer()
+ * @len: Buffer length returned by get_rx_buffer()
+ */
+struct smux_meta_write {
+ void *pkt_priv;
+ void *buffer;
+ int len;
+};
+
+/**
+ * Metadata for SMUX_TIOCM_UPDATE notification
+ *
+ * @tiocm_old: Previous TIOCM state
+ * @tiocm_new: Current TIOCM state
+ */
+struct smux_meta_tiocm {
+ uint32_t tiocm_old;
+ uint32_t tiocm_new;
+};
+
+
+#ifdef CONFIG_N_SMUX
+/**
+ * Starts the opening sequence for a logical channel.
+ *
+ * @lcid Logical channel ID
+ * @priv Free for client usage
+ * @notify Event notification function
+ * @get_rx_buffer Function used to provide a receive buffer to SMUX
+ *
+ * @returns 0 for success, <0 otherwise
+ *
+ * A channel must be fully closed (either not previously opened or
+ * msm_smux_close() has been called and the SMUX_DISCONNECTED has been
+ * recevied.
+ *
+ * One the remote side is opened, the client will receive a SMUX_CONNECTED
+ * event.
+ */
+int msm_smux_open(uint8_t lcid, void *priv,
+ void (*notify)(void *priv, int event_type, const void *metadata),
+ int (*get_rx_buffer)(void *priv, void **pkt_priv,
+ void **buffer, int size));
+
+/**
+ * Starts the closing sequence for a logical channel.
+ *
+ * @lcid Logical channel ID
+ * @returns 0 for success, <0 otherwise
+ *
+ * Once the close event has been acknowledge by the remote side, the client
+ * will receive a SMUX_DISCONNECTED notification.
+ */
+int msm_smux_close(uint8_t lcid);
+
+/**
+ * Write data to a logical channel.
+ *
+ * @lcid Logical channel ID
+ * @pkt_priv Client data that will be returned with the SMUX_WRITE_DONE or
+ * SMUX_WRITE_FAIL notification.
+ * @data Data to write
+ * @len Length of @data
+ *
+ * @returns 0 for success, <0 otherwise
+ *
+ * Data may be written immediately after msm_smux_open() is called, but
+ * the data will wait in the transmit queue until the channel has been
+ * fully opened.
+ *
+ * Once the data has been written, the client will receive either a completion
+ * (SMUX_WRITE_DONE) or a failure notice (SMUX_WRITE_FAIL).
+ */
+int msm_smux_write(uint8_t lcid, void *pkt_priv, const void *data, int len);
+
+/**
+ * Returns true if the TX queue is currently full (high water mark).
+ *
+ * @lcid Logical channel ID
+ *
+ * @returns 0 if channel is not full; 1 if it is full; < 0 for error
+ */
+int msm_smux_is_ch_full(uint8_t lcid);
+
+/**
+ * Returns true if the TX queue has space for more packets it is at or
+ * below the low water mark).
+ *
+ * @lcid Logical channel ID
+ *
+ * @returns 0 if channel is above low watermark
+ * 1 if it's at or below the low watermark
+ * < 0 for error
+ */
+int msm_smux_is_ch_low(uint8_t lcid);
+
+/**
+ * Get the TIOCM status bits.
+ *
+ * @lcid Logical channel ID
+ *
+ * @returns >= 0 TIOCM status bits
+ * < 0 Error condition
+ */
+long msm_smux_tiocm_get(uint8_t lcid);
+
+/**
+ * Set/clear the TIOCM status bits.
+ *
+ * @lcid Logical channel ID
+ * @set Bits to set
+ * @clear Bits to clear
+ *
+ * @returns 0 for success; < 0 for failure
+ *
+ * If a bit is specified in both the @set and @clear masks, then the clear bit
+ * definition will dominate and the bit will be cleared.
+ */
+int msm_smux_tiocm_set(uint8_t lcid, uint32_t set, uint32_t clear);
+
+/**
+ * Set or clear channel option using the SMUX_CH_OPTION_* channel
+ * flags.
+ *
+ * @lcid Logical channel ID
+ * @set Options to set
+ * @clear Options to clear
+ *
+ * @returns 0 for success, < 0 for failure
+ */
+int msm_smux_set_ch_option(uint8_t lcid, uint32_t set, uint32_t clear);
+
+#else
+int msm_smux_open(uint8_t lcid, void *priv,
+ void (*notify)(void *priv, int event_type, const void *metadata),
+ int (*get_rx_buffer)(void *priv, void **pkt_priv,
+ void **buffer, int size))
+{
+ return -ENODEV;
+}
+
+int msm_smux_close(uint8_t lcid)
+{
+ return -ENODEV;
+}
+
+int msm_smux_write(uint8_t lcid, void *pkt_priv, const void *data, int len)
+{
+ return -ENODEV;
+}
+
+int msm_smux_is_ch_full(uint8_t lcid);
+{
+ return -ENODEV;
+}
+
+int msm_smux_is_ch_low(uint8_t lcid);
+{
+ return -ENODEV;
+}
+
+long msm_smux_tiocm_get(uint8_t lcid)
+{
+ return 0;
+}
+
+int msm_smux_tiocm_set(uint8_t lcid, uint32_t set, uint32_t clear)
+{
+ return -ENODEV;
+}
+
+int msm_smux_set_ch_option(uint8_t lcid, uint32_t set, uint32_t clear)
+{
+ return -ENODEV;
+}
+
+#endif /* CONFIG_N_SMUX */
+
+#endif /* SMUX_H */