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, 88 insertions, 0 deletions

diff --git a/drivers/net/wwan/iosm/iosm_ipc_chnl_cfg.c b/drivers/net/wwan/iosm/iosm_ipc_chnl_cfg.c
new file mode 100644
index 000000000000..804e6c4f2c78
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_chnl_cfg.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020-21 Intel Corporation.
+ */
+
+#include <linux/wwan.h>
+
+#include "iosm_ipc_chnl_cfg.h"
+
+/* Max. sizes of a downlink buffers */
+#define IPC_MEM_MAX_DL_FLASH_BUF_SIZE (16 * 1024)
+#define IPC_MEM_MAX_DL_LOOPBACK_SIZE (1 * 1024 * 1024)
+#define IPC_MEM_MAX_DL_AT_BUF_SIZE 2048
+#define IPC_MEM_MAX_DL_RPC_BUF_SIZE (32 * 1024)
+#define IPC_MEM_MAX_DL_MBIM_BUF_SIZE IPC_MEM_MAX_DL_RPC_BUF_SIZE
+
+/* Max. transfer descriptors for a pipe. */
+#define IPC_MEM_MAX_TDS_FLASH_DL 3
+#define IPC_MEM_MAX_TDS_FLASH_UL 6
+#define IPC_MEM_MAX_TDS_AT 4
+#define IPC_MEM_MAX_TDS_RPC 4
+#define IPC_MEM_MAX_TDS_MBIM IPC_MEM_MAX_TDS_RPC
+#define IPC_MEM_MAX_TDS_LOOPBACK 11
+
+/* Accumulation backoff usec */
+#define IRQ_ACC_BACKOFF_OFF 0
+
+/* MUX acc backoff 1ms */
+#define IRQ_ACC_BACKOFF_MUX 1000
+
+/* Modem channel configuration table
+ * Always reserve element zero for flash channel.
+ */
+static struct ipc_chnl_cfg modem_cfg[] = {
+	/* IP Mux */
+	{ IPC_MEM_IP_CHL_ID_0, IPC_MEM_PIPE_0, IPC_MEM_PIPE_1,
+	  IPC_MEM_MAX_TDS_MUX_LITE_UL, IPC_MEM_MAX_TDS_MUX_LITE_DL,
+	  IPC_MEM_MAX_DL_MUX_LITE_BUF_SIZE, WWAN_PORT_UNKNOWN },
+	/* RPC - 0 */
+	{ IPC_MEM_CTRL_CHL_ID_1, IPC_MEM_PIPE_2, IPC_MEM_PIPE_3,
+	  IPC_MEM_MAX_TDS_RPC, IPC_MEM_MAX_TDS_RPC,
+	  IPC_MEM_MAX_DL_RPC_BUF_SIZE, WWAN_PORT_UNKNOWN },
+	/* IAT0 */
+	{ IPC_MEM_CTRL_CHL_ID_2, IPC_MEM_PIPE_4, IPC_MEM_PIPE_5,
+	  IPC_MEM_MAX_TDS_AT, IPC_MEM_MAX_TDS_AT, IPC_MEM_MAX_DL_AT_BUF_SIZE,
+	  WWAN_PORT_AT },
+	/* Trace */
+	{ IPC_MEM_CTRL_CHL_ID_3, IPC_MEM_PIPE_6, IPC_MEM_PIPE_7,
+	  IPC_MEM_TDS_TRC, IPC_MEM_TDS_TRC, IPC_MEM_MAX_DL_TRC_BUF_SIZE,
+	  WWAN_PORT_UNKNOWN },
+	/* IAT1 */
+	{ IPC_MEM_CTRL_CHL_ID_4, IPC_MEM_PIPE_8, IPC_MEM_PIPE_9,
+	  IPC_MEM_MAX_TDS_AT, IPC_MEM_MAX_TDS_AT, IPC_MEM_MAX_DL_AT_BUF_SIZE,
+	  WWAN_PORT_AT },
+	/* Loopback */
+	{ IPC_MEM_CTRL_CHL_ID_5, IPC_MEM_PIPE_10, IPC_MEM_PIPE_11,
+	  IPC_MEM_MAX_TDS_LOOPBACK, IPC_MEM_MAX_TDS_LOOPBACK,
+	  IPC_MEM_MAX_DL_LOOPBACK_SIZE, WWAN_PORT_UNKNOWN },
+	/* MBIM Channel */
+	{ IPC_MEM_CTRL_CHL_ID_6, IPC_MEM_PIPE_12, IPC_MEM_PIPE_13,
+	  IPC_MEM_MAX_TDS_MBIM, IPC_MEM_MAX_TDS_MBIM,
+	  IPC_MEM_MAX_DL_MBIM_BUF_SIZE, WWAN_PORT_MBIM },
+};
+
+int ipc_chnl_cfg_get(struct ipc_chnl_cfg *chnl_cfg, int index)
+{
+	int array_size = ARRAY_SIZE(modem_cfg);
+
+	if (index >= array_size) {
+		pr_err("index: %d and array_size %d", index, array_size);
+		return -ECHRNG;
+	}
+
+	if (index == IPC_MEM_MUX_IP_CH_IF_ID)
+		chnl_cfg->accumulation_backoff = IRQ_ACC_BACKOFF_MUX;
+	else
+		chnl_cfg->accumulation_backoff = IRQ_ACC_BACKOFF_OFF;
+
+	chnl_cfg->ul_nr_of_entries = modem_cfg[index].ul_nr_of_entries;
+	chnl_cfg->dl_nr_of_entries = modem_cfg[index].dl_nr_of_entries;
+	chnl_cfg->dl_buf_size = modem_cfg[index].dl_buf_size;
+	chnl_cfg->id = modem_cfg[index].id;
+	chnl_cfg->ul_pipe = modem_cfg[index].ul_pipe;
+	chnl_cfg->dl_pipe = modem_cfg[index].dl_pipe;
+	chnl_cfg->wwan_port_type = modem_cfg[index].wwan_port_type;
+
+	return 0;
+}