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, 193 insertions, 0 deletions

diff --git a/drivers/net/wwan/iosm/iosm_ipc_mux_codec.h b/drivers/net/wwan/iosm/iosm_ipc_mux_codec.h
new file mode 100644
index 000000000000..4a74e3c9457f
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_mux_codec.h
@@ -0,0 +1,193 @@
+/* SPDX-License-Identifier: GPL-2.0-only
+ *
+ * Copyright (C) 2020-21 Intel Corporation.
+ */
+
+#ifndef IOSM_IPC_MUX_CODEC_H
+#define IOSM_IPC_MUX_CODEC_H
+
+#include "iosm_ipc_mux.h"
+
+/* Queue level size and reporting
+ * >1 is enable, 0 is disable
+ */
+#define MUX_QUEUE_LEVEL 1
+
+/* Size of the buffer for the IP MUX commands. */
+#define MUX_MAX_UL_ACB_BUF_SIZE 256
+
+/* Maximum number of packets in a go per session */
+#define MUX_MAX_UL_DG_ENTRIES 100
+
+/* ADGH: Signature of the Datagram Header. */
+#define MUX_SIG_ADGH 0x48474441
+
+/* CMDH: Signature of the Command Header. */
+#define MUX_SIG_CMDH 0x48444D43
+
+/* QLTH: Signature of the Queue Level Table */
+#define MUX_SIG_QLTH 0x48544C51
+
+/* FCTH: Signature of the Flow Credit Table */
+#define MUX_SIG_FCTH 0x48544346
+
+/* MUX UL session threshold factor */
+#define IPC_MEM_MUX_UL_SESS_FCOFF_THRESHOLD_FACTOR (4)
+
+/* Size of the buffer for the IP MUX Lite data buffer. */
+#define IPC_MEM_MAX_DL_MUX_LITE_BUF_SIZE (2 * 1024)
+
+/* MUX UL session threshold in number of packets */
+#define IPC_MEM_MUX_UL_SESS_FCON_THRESHOLD (64)
+
+/* Default time out for sending IPC session commands like
+ * open session, close session etc
+ * unit : milliseconds
+ */
+#define IPC_MUX_CMD_RUN_DEFAULT_TIMEOUT 1000 /* 1 second */
+
+/* MUX UL flow control lower threshold in bytes */
+#define IPC_MEM_MUX_UL_FLOWCTRL_LOW_B 10240 /* 10KB */
+
+/* MUX UL flow control higher threshold in bytes (5ms worth of data)*/
+#define IPC_MEM_MUX_UL_FLOWCTRL_HIGH_B (110 * 1024)
+
+/**
+ * struct mux_adgh - Aggregated Datagram Header.
+ * @signature:		Signature of the Aggregated Datagram Header(0x48474441)
+ * @length:		Length (in bytes) of the datagram header. This length
+ *			shall include the header size. Min value: 0x10
+ * @if_id:		ID of the interface the datagrams belong to
+ * @opt_ipv4v6:		Indicates IPv4(=0)/IPv6(=1), It is optional if not
+ *			used set it to zero.
+ * @reserved:		Reserved bits. Set to zero.
+ * @service_class:	Service class identifier for the datagram.
+ * @next_count:		Count of the datagrams that shall be following this
+ *			datagrams for this interface. A count of zero means
+ *			the next datagram may not belong to this interface.
+ * @reserved1:		Reserved bytes, Set to zero
+ */
+struct mux_adgh {
+	__le32 signature;
+	__le16 length;
+	u8 if_id;
+	u8 opt_ipv4v6;
+	u8 service_class;
+	u8 next_count;
+	u8 reserved1[6];
+};
+
+/**
+ * struct mux_lite_cmdh - MUX Lite Command Header
+ * @signature:		Signature of the Command Header(0x48444D43)
+ * @cmd_len:		Length (in bytes) of the command. This length shall
+ *			include the header size. Minimum value: 0x10
+ * @if_id:		ID of the interface the commands in the table belong to.
+ * @reserved:		Reserved Set to zero.
+ * @command_type:	Command Enum.
+ * @transaction_id:	4 byte value shall be generated and sent along with a
+ *			command Responses and ACKs shall have the same
+ *			Transaction ID as their commands. It shall be unique to
+ *			the command transaction on the given interface.
+ * @param:		Optional parameters used with the command.
+ */
+struct mux_lite_cmdh {
+	__le32 signature;
+	__le16 cmd_len;
+	u8 if_id;
+	u8 reserved;
+	__le32 command_type;
+	__le32 transaction_id;
+	union mux_cmd_param param;
+};
+
+/**
+ * struct mux_lite_vfl - value field in generic table
+ * @nr_of_bytes:	Number of bytes available to transmit in the queue.
+ */
+struct mux_lite_vfl {
+	u32 nr_of_bytes;
+};
+
+/**
+ * struct ipc_mem_lite_gen_tbl - Generic table format for Queue Level
+ *				 and Flow Credit
+ * @signature:	Signature of the table
+ * @length:	Length of the table
+ * @if_id:	ID of the interface the table belongs to
+ * @vfl_length:	Value field length
+ * @reserved:	Reserved
+ * @vfl:	Value field of variable length
+ */
+struct ipc_mem_lite_gen_tbl {
+	__le32 signature;
+	__le16 length;
+	u8 if_id;
+	u8 vfl_length;
+	u32 reserved[2];
+	struct mux_lite_vfl vfl;
+};
+
+/**
+ * ipc_mux_dl_decode -Route the DL packet through the IP MUX layer
+ *		      depending on Header.
+ * @ipc_mux:	Pointer to MUX data-struct
+ * @skb:	Pointer to ipc_skb.
+ */
+void ipc_mux_dl_decode(struct iosm_mux *ipc_mux, struct sk_buff *skb);
+
+/**
+ * ipc_mux_dl_acb_send_cmds - Respond to the Command blocks.
+ * @ipc_mux:		Pointer to MUX data-struct
+ * @cmd_type:		Command
+ * @if_id:		Session interface id.
+ * @transaction_id:	Command transaction id.
+ * @param:		Pointer to command params.
+ * @res_size:		Response size
+ * @blocking:		True for blocking send
+ * @respond:		If true return transaction ID
+ *
+ * Returns: 0 in success and failure value on error
+ */
+int ipc_mux_dl_acb_send_cmds(struct iosm_mux *ipc_mux, u32 cmd_type, u8 if_id,
+			     u32 transaction_id, union mux_cmd_param *param,
+			     size_t res_size, bool blocking, bool respond);
+
+/**
+ * ipc_mux_netif_tx_flowctrl - Enable/Disable TX flow control on MUX sessions.
+ * @session:	Pointer to mux_session struct
+ * @idx:	Session ID
+ * @on:		true for Enable and false for disable flow control
+ */
+void ipc_mux_netif_tx_flowctrl(struct mux_session *session, int idx, bool on);
+
+/**
+ * ipc_mux_ul_trigger_encode - Route the UL packet through the IP MUX layer
+ *			       for encoding.
+ * @ipc_mux:	Pointer to MUX data-struct
+ * @if_id:	Session ID.
+ * @skb:	Pointer to ipc_skb.
+ *
+ * Returns: 0 if successfully encoded
+ *	    failure value on error
+ *	    -EBUSY if packet has to be retransmitted.
+ */
+int ipc_mux_ul_trigger_encode(struct iosm_mux *ipc_mux, int if_id,
+			      struct sk_buff *skb);
+/**
+ * ipc_mux_ul_data_encode - UL encode function for calling from Tasklet context.
+ * @ipc_mux:	Pointer to MUX data-struct
+ *
+ * Returns: TRUE if any packet of any session is encoded FALSE otherwise.
+ */
+bool ipc_mux_ul_data_encode(struct iosm_mux *ipc_mux);
+
+/**
+ * ipc_mux_ul_encoded_process - Handles the Modem processed UL data by adding
+ *				the SKB to the UL free list.
+ * @ipc_mux:	Pointer to MUX data-struct
+ * @skb:	Pointer to ipc_skb.
+ */
+void ipc_mux_ul_encoded_process(struct iosm_mux *ipc_mux, struct sk_buff *skb);
+
+#endif