Merge branch 'iosm-driver'

M Chetan Kumar says:

====================
net: iosm: PCIe Driver for Intel M.2 Modem

The IOSM (IPC over Shared Memory) driver is a PCIe host driver implemented
for linux or chrome platform for data exchange over PCIe interface between
Host platform & Intel M.2 Modem. The driver exposes interface conforming to
the MBIM protocol. Any front end application ( eg: Modem Manager) could
easily manage the MBIM interface to enable data communication towards WWAN.

Intel M.2 modem uses 2 BAR regions. The first region is dedicated to Doorbell
register for IRQs and the second region is used as scratchpad area for book
keeping modem execution stage details along with host system shared memory
region context details. The upper edge of the driver exposes the control and
data channels for user space application interaction. At lower edge these data
and control channels are associated to pipes. The pipes are lowest level
interfaces used over PCIe as a logical channel for message exchange. A single
channel maps to UL and DL pipe and are initialized on device open.

On UL path, driver copies application sent data to SKBs associate it with
transfer descriptor and puts it on to ring buffer for DMA transfer. Once
information has been updated in shared memory region, host gives a Doorbell
to modem to perform DMA and modem uses MSI to communicate back to host.
For receiving data in DL path, SKBs are pre-allocated during pipe open and
transfer descriptors are given to modem for DMA transfer.

The driver exposes two types of ports, namely "wwan0mbim0", a char device node
which is used for MBIM control operation and "wwan0-x",(x = 0,1,2..7) network
interfaces for IP data communication.
1) MBIM Control Interface:
This node exposes an interface between modem and application using char device
exposed by "IOSM" driver to establish and manage the MBIM data communication
with PCIe based Intel M.2 Modems.

2) MBIM Data Interface:
The IOSM driver exposes IP link interface "wwan0-x" of type "wwan" for IP traffic.
Iproute network utility is used for creating "wwan0-x" network interface and for
associating it with MBIM IP session. The Driver supports upto 8 IP sessions for
simultaneous IP communication.

This applies on top of WWAN core rtnetlink series posted here:
https://lore.kernel.org/netdev/1623486057-13075-1-git-send-email-loic.poulain@linaro.org/

Also driver has been compiled and tested on top of netdev net-next tree.
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 343 insertions, 0 deletions

diff --git a/drivers/net/wwan/iosm/iosm_ipc_mux.h b/drivers/net/wwan/iosm/iosm_ipc_mux.h
new file mode 100644
index 000000000000..ddd2cd0bd911
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_mux.h
@@ -0,0 +1,343 @@
+/* SPDX-License-Identifier: GPL-2.0-only
+ *
+ * Copyright (C) 2020-21 Intel Corporation.
+ */
+
+#ifndef IOSM_IPC_MUX_H
+#define IOSM_IPC_MUX_H
+
+#include "iosm_ipc_protocol.h"
+
+/* Size of the buffer for the IP MUX data buffer. */
+#define IPC_MEM_MAX_DL_MUX_BUF_SIZE (16 * 1024)
+#define IPC_MEM_MAX_UL_ADB_BUF_SIZE IPC_MEM_MAX_DL_MUX_BUF_SIZE
+
+/* Size of the buffer for the IP MUX Lite data buffer. */
+#define IPC_MEM_MAX_DL_MUX_LITE_BUF_SIZE (2 * 1024)
+
+/* TD counts for IP MUX Lite */
+#define IPC_MEM_MAX_TDS_MUX_LITE_UL 800
+#define IPC_MEM_MAX_TDS_MUX_LITE_DL 1200
+
+/* open session request (AP->CP) */
+#define MUX_CMD_OPEN_SESSION 1
+
+/* response to open session request (CP->AP) */
+#define MUX_CMD_OPEN_SESSION_RESP 2
+
+/* close session request (AP->CP) */
+#define MUX_CMD_CLOSE_SESSION 3
+
+/* response to close session request (CP->AP) */
+#define MUX_CMD_CLOSE_SESSION_RESP 4
+
+/* Flow control command with mask of the flow per queue/flow. */
+#define MUX_LITE_CMD_FLOW_CTL 5
+
+/* ACK the flow control command. Shall have the same Transaction ID as the
+ * matching FLOW_CTL command.
+ */
+#define MUX_LITE_CMD_FLOW_CTL_ACK 6
+
+/* Command for report packet indicating link quality metrics. */
+#define MUX_LITE_CMD_LINK_STATUS_REPORT 7
+
+/* Response to a report packet */
+#define MUX_LITE_CMD_LINK_STATUS_REPORT_RESP 8
+
+/* Used to reset a command/response state. */
+#define MUX_CMD_INVALID 255
+
+/* command response : command processed successfully */
+#define MUX_CMD_RESP_SUCCESS 0
+
+/* MUX for route link devices */
+#define IPC_MEM_WWAN_MUX BIT(0)
+
+/* Initiated actions to change the state of the MUX object. */
+enum mux_event {
+	MUX_E_INACTIVE, /* No initiated actions. */
+	MUX_E_MUX_SESSION_OPEN, /* Create the MUX channel and a session. */
+	MUX_E_MUX_SESSION_CLOSE, /* Release a session. */
+	MUX_E_MUX_CHANNEL_CLOSE, /* Release the MUX channel. */
+	MUX_E_NO_ORDERS, /* No MUX order. */
+	MUX_E_NOT_APPLICABLE, /* Defect IP MUX. */
+};
+
+/* MUX session open command. */
+struct mux_session_open {
+	enum mux_event event;
+	__le32 if_id;
+};
+
+/* MUX session close command. */
+struct mux_session_close {
+	enum mux_event event;
+	__le32 if_id;
+};
+
+/* MUX channel close command. */
+struct mux_channel_close {
+	enum mux_event event;
+};
+
+/* Default message type to find out the right message type. */
+struct mux_common {
+	enum mux_event event;
+};
+
+/* List of ops in MUX mode. */
+union mux_msg {
+	struct mux_session_open session_open;
+	struct mux_session_close session_close;
+	struct mux_channel_close channel_close;
+	struct mux_common common;
+};
+
+/* Parameter definition of the open session command. */
+struct mux_cmd_open_session {
+	u8 flow_ctrl; /* 0: Flow control disabled (flow allowed). */
+	/* 1: Flow control enabled (flow not allowed)*/
+	u8 ipv4v6_hints; /* 0: IPv4/IPv6 hints not supported.*/
+	/* 1: IPv4/IPv6 hints supported*/
+	__le16 reserved2; /* Reserved. Set to zero. */
+	__le32 dl_head_pad_len; /* Maximum length supported */
+	/* for DL head padding on a datagram. */
+};
+
+/* Parameter definition of the open session response. */
+struct mux_cmd_open_session_resp {
+	__le32 response; /* Response code */
+	u8 flow_ctrl; /* 0: Flow control disabled (flow allowed). */
+	/* 1: Flow control enabled (flow not allowed) */
+	u8 ipv4v6_hints; /* 0: IPv4/IPv6 hints not supported */
+	/* 1: IPv4/IPv6 hints supported */
+	__le16 reserved2; /* Reserved. Set to zero. */
+	__le32 ul_head_pad_len; /* Actual length supported for */
+	/* UL head padding on adatagram.*/
+};
+
+/* Parameter definition of the close session response code */
+struct mux_cmd_close_session_resp {
+	__le32 response;
+};
+
+/* Parameter definition of the flow control command. */
+struct mux_cmd_flow_ctl {
+	__le32 mask; /* indicating the desired flow control */
+	/* state for various flows/queues */
+};
+
+/* Parameter definition of the link status report code*/
+struct mux_cmd_link_status_report {
+	u8 payload;
+};
+
+/* Parameter definition of the link status report response code. */
+struct mux_cmd_link_status_report_resp {
+	__le32 response;
+};
+
+/**
+ * union mux_cmd_param - Union-definition of the command parameters.
+ * @open_session:	Inband command for open session
+ * @open_session_resp:	Inband command for open session response
+ * @close_session_resp:	Inband command for close session response
+ * @flow_ctl:		In-band flow control on the opened interfaces
+ * @link_status:	In-band Link Status Report
+ * @link_status_resp:	In-band command for link status report response
+ */
+union mux_cmd_param {
+	struct mux_cmd_open_session open_session;
+	struct mux_cmd_open_session_resp open_session_resp;
+	struct mux_cmd_close_session_resp close_session_resp;
+	struct mux_cmd_flow_ctl flow_ctl;
+	struct mux_cmd_link_status_report link_status;
+	struct mux_cmd_link_status_report_resp link_status_resp;
+};
+
+/* States of the MUX object.. */
+enum mux_state {
+	MUX_S_INACTIVE, /* IP MUX is unused. */
+	MUX_S_ACTIVE, /* IP MUX channel is available. */
+	MUX_S_ERROR, /* Defect IP MUX. */
+};
+
+/* Supported MUX protocols. */
+enum ipc_mux_protocol {
+	MUX_UNKNOWN,
+	MUX_LITE,
+};
+
+/* Supported UL data transfer methods. */
+enum ipc_mux_ul_flow {
+	MUX_UL_UNKNOWN,
+	MUX_UL, /* Normal UL data transfer */
+	MUX_UL_ON_CREDITS, /* UL data transfer will be based on credits */
+};
+
+/* List of the MUX session. */
+struct mux_session {
+	struct iosm_wwan *wwan; /*Network i/f used for communication*/
+	int if_id; /* i/f id for session open message.*/
+	u32 flags;
+	u32 ul_head_pad_len; /* Nr of bytes for UL head padding. */
+	u32 dl_head_pad_len; /* Nr of bytes for DL head padding. */
+	struct sk_buff_head ul_list; /* skb entries for an ADT. */
+	u32 flow_ctl_mask; /* UL flow control */
+	u32 flow_ctl_en_cnt; /* Flow control Enable cmd count */
+	u32 flow_ctl_dis_cnt; /* Flow Control Disable cmd count */
+	int ul_flow_credits; /* UL flow credits */
+	u8 net_tx_stop:1,
+	   flush:1; /* flush net interface ? */
+};
+
+/* State of a single UL data block. */
+struct mux_adb {
+	struct sk_buff *dest_skb; /* Current UL skb for the data block. */
+	u8 *buf; /* ADB memory. */
+	struct mux_adgh *adgh; /* ADGH pointer */
+	struct sk_buff *qlth_skb; /* QLTH pointer */
+	u32 *next_table_index; /* Pointer to next table index. */
+	struct sk_buff_head free_list; /* List of alloc. ADB for the UL sess.*/
+	int size; /* Size of the ADB memory. */
+	u32 if_cnt; /* Statistic counter */
+	u32 dg_cnt_total;
+	u32 payload_size;
+};
+
+/* Temporary ACB state. */
+struct mux_acb {
+	struct sk_buff *skb; /* Used UL skb. */
+	int if_id; /* Session id. */
+	u32 wanted_response;
+	u32 got_response;
+	u32 cmd;
+	union mux_cmd_param got_param; /* Received command/response parameter */
+};
+
+/**
+ * struct iosm_mux - Structure of the data multiplexing over an IP channel.
+ * @dev:		Pointer to device structure
+ * @session:		Array of the MUX sessions.
+ * @channel:		Reference to the IP MUX channel
+ * @pcie:		Pointer to iosm_pcie struct
+ * @imem:		Pointer to iosm_imem
+ * @wwan:		Poinetr to iosm_wwan
+ * @ipc_protocol:	Pointer to iosm_protocol
+ * @channel_id:		Channel ID for MUX
+ * @protocol:		Type of the MUX protocol
+ * @ul_flow:		UL Flow type
+ * @nr_sessions:	Number of sessions
+ * @instance_id:	Instance ID
+ * @state:		States of the MUX object
+ * @event:		Initiated actions to change the state of the MUX object
+ * @tx_transaction_id:	Transaction id for the ACB command.
+ * @rr_next_session:	Next session number for round robin.
+ * @ul_adb:		State of the UL ADB/ADGH.
+ * @size_needed:	Variable to store the size needed during ADB preparation
+ * @ul_data_pend_bytes:	Pending UL data to be processed in bytes
+ * @acb:		Temporary ACB state
+ * @wwan_q_offset:	This will hold the offset of the given instance
+ *			Useful while passing or receiving packets from
+ *			wwan/imem layer.
+ * @initialized:	MUX object is initialized
+ * @ev_mux_net_transmit_pending:
+ *			0 means inform the IPC tasklet to pass the
+ *			accumulated uplink ADB to CP.
+ * @adb_prep_ongoing:	Flag for ADB preparation status
+ */
+struct iosm_mux {
+	struct device *dev;
+	struct mux_session session[IPC_MEM_MUX_IP_SESSION_ENTRIES];
+	struct ipc_mem_channel *channel;
+	struct iosm_pcie *pcie;
+	struct iosm_imem *imem;
+	struct iosm_wwan *wwan;
+	struct iosm_protocol *ipc_protocol;
+	int channel_id;
+	enum ipc_mux_protocol protocol;
+	enum ipc_mux_ul_flow ul_flow;
+	int nr_sessions;
+	int instance_id;
+	enum mux_state state;
+	enum mux_event event;
+	u32 tx_transaction_id;
+	int rr_next_session;
+	struct mux_adb ul_adb;
+	int size_needed;
+	long long ul_data_pend_bytes;
+	struct mux_acb acb;
+	int wwan_q_offset;
+	u8 initialized:1,
+	   ev_mux_net_transmit_pending:1,
+	   adb_prep_ongoing:1;
+};
+
+/* MUX configuration structure */
+struct ipc_mux_config {
+	enum ipc_mux_protocol protocol;
+	enum ipc_mux_ul_flow ul_flow;
+	int nr_sessions;
+	int instance_id;
+};
+
+/**
+ * ipc_mux_init - Allocates and Init MUX instance
+ * @mux_cfg:	Pointer to MUX configuration structure
+ * @ipc_imem:	Pointer to imem data-struct
+ *
+ * Returns: Initialized mux pointer on success else NULL
+ */
+struct iosm_mux *ipc_mux_init(struct ipc_mux_config *mux_cfg,
+			      struct iosm_imem *ipc_imem);
+
+/**
+ * ipc_mux_deinit - Deallocates MUX instance
+ * @ipc_mux:	Pointer to the MUX instance.
+ */
+void ipc_mux_deinit(struct iosm_mux *ipc_mux);
+
+/**
+ * ipc_mux_check_n_restart_tx - Checks for pending UL date bytes and then
+ *				it restarts the net interface tx queue if
+ *				device has set flow control as off.
+ * @ipc_mux:	Pointer to MUX data-struct
+ */
+void ipc_mux_check_n_restart_tx(struct iosm_mux *ipc_mux);
+
+/**
+ * ipc_mux_get_active_protocol - Returns the active MUX protocol type.
+ * @ipc_mux:	Pointer to MUX data-struct
+ *
+ * Returns: enum of type ipc_mux_protocol
+ */
+enum ipc_mux_protocol ipc_mux_get_active_protocol(struct iosm_mux *ipc_mux);
+
+/**
+ * ipc_mux_open_session - Opens a MUX session for IP traffic.
+ * @ipc_mux:	Pointer to MUX data-struct
+ * @session_nr:	Interface ID or session number
+ *
+ * Returns: channel id on success, failure value on error
+ */
+int ipc_mux_open_session(struct iosm_mux *ipc_mux, int session_nr);
+
+/**
+ * ipc_mux_close_session - Closes a MUX session.
+ * @ipc_mux:	Pointer to MUX data-struct
+ * @session_nr:	Interface ID or session number
+ *
+ * Returns: channel id on success, failure value on error
+ */
+int ipc_mux_close_session(struct iosm_mux *ipc_mux, int session_nr);
+
+/**
+ * ipc_mux_get_max_sessions - Retuns the maximum sessions supported on the
+ *			      provided MUX instance..
+ * @ipc_mux:	Pointer to MUX data-struct
+ *
+ * Returns: Number of sessions supported on Success and failure value on error
+ */
+int ipc_mux_get_max_sessions(struct iosm_mux *ipc_mux);
+#endif