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, 223 insertions, 0 deletions

diff --git a/drivers/net/wwan/iosm/iosm_ipc_mmio.c b/drivers/net/wwan/iosm/iosm_ipc_mmio.c
new file mode 100644
index 000000000000..06c94b1720b6
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_mmio.c
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020-21 Intel Corporation.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/slab.h>
+
+#include "iosm_ipc_mmio.h"
+
+/* Definition of MMIO offsets
+ * note that MMIO_CI offsets are relative to end of chip info structure
+ */
+
+/* MMIO chip info size in bytes */
+#define MMIO_CHIP_INFO_SIZE 60
+
+/* CP execution stage */
+#define MMIO_OFFSET_EXECUTION_STAGE 0x00
+
+/* Boot ROM Chip Info struct */
+#define MMIO_OFFSET_CHIP_INFO 0x04
+
+#define MMIO_OFFSET_ROM_EXIT_CODE 0x40
+
+#define MMIO_OFFSET_PSI_ADDRESS 0x54
+
+#define MMIO_OFFSET_PSI_SIZE 0x5C
+
+#define MMIO_OFFSET_IPC_STATUS 0x60
+
+#define MMIO_OFFSET_CONTEXT_INFO 0x64
+
+#define MMIO_OFFSET_BASE_ADDR 0x6C
+
+#define MMIO_OFFSET_END_ADDR 0x74
+
+#define MMIO_OFFSET_CP_VERSION 0xF0
+
+#define MMIO_OFFSET_CP_CAPABILITIES 0xF4
+
+/* Timeout in 50 msec to wait for the modem boot code to write a valid
+ * execution stage into mmio area
+ */
+#define IPC_MMIO_EXEC_STAGE_TIMEOUT 50
+
+/* check if exec stage has one of the valid values */
+static bool ipc_mmio_is_valid_exec_stage(enum ipc_mem_exec_stage stage)
+{
+	switch (stage) {
+	case IPC_MEM_EXEC_STAGE_BOOT:
+	case IPC_MEM_EXEC_STAGE_PSI:
+	case IPC_MEM_EXEC_STAGE_EBL:
+	case IPC_MEM_EXEC_STAGE_RUN:
+	case IPC_MEM_EXEC_STAGE_CRASH:
+	case IPC_MEM_EXEC_STAGE_CD_READY:
+		return true;
+	default:
+		return false;
+	}
+}
+
+void ipc_mmio_update_cp_capability(struct iosm_mmio *ipc_mmio)
+{
+	u32 cp_cap;
+	unsigned int ver;
+
+	ver = ipc_mmio_get_cp_version(ipc_mmio);
+	cp_cap = readl(ipc_mmio->base + ipc_mmio->offset.cp_capability);
+
+	ipc_mmio->has_mux_lite = (ver >= IOSM_CP_VERSION) &&
+				 !(cp_cap & DL_AGGR) && !(cp_cap & UL_AGGR);
+
+	ipc_mmio->has_ul_flow_credit =
+		(ver >= IOSM_CP_VERSION) && (cp_cap & UL_FLOW_CREDIT);
+}
+
+struct iosm_mmio *ipc_mmio_init(void __iomem *mmio, struct device *dev)
+{
+	struct iosm_mmio *ipc_mmio = kzalloc(sizeof(*ipc_mmio), GFP_KERNEL);
+	int retries = IPC_MMIO_EXEC_STAGE_TIMEOUT;
+	enum ipc_mem_exec_stage stage;
+
+	if (!ipc_mmio)
+		return NULL;
+
+	ipc_mmio->dev = dev;
+
+	ipc_mmio->base = mmio;
+
+	ipc_mmio->offset.exec_stage = MMIO_OFFSET_EXECUTION_STAGE;
+
+	/* Check for a valid execution stage to make sure that the boot code
+	 * has correctly initialized the MMIO area.
+	 */
+	do {
+		stage = ipc_mmio_get_exec_stage(ipc_mmio);
+		if (ipc_mmio_is_valid_exec_stage(stage))
+			break;
+
+		msleep(20);
+	} while (retries-- > 0);
+
+	if (!retries) {
+		dev_err(ipc_mmio->dev, "invalid exec stage %X", stage);
+		goto init_fail;
+	}
+
+	ipc_mmio->offset.chip_info = MMIO_OFFSET_CHIP_INFO;
+
+	/* read chip info size and version from chip info structure */
+	ipc_mmio->chip_info_version =
+		ioread8(ipc_mmio->base + ipc_mmio->offset.chip_info);
+
+	/* Increment of 2 is needed as the size value in the chip info
+	 * excludes the version and size field, which are always present
+	 */
+	ipc_mmio->chip_info_size =
+		ioread8(ipc_mmio->base + ipc_mmio->offset.chip_info + 1) + 2;
+
+	if (ipc_mmio->chip_info_size != MMIO_CHIP_INFO_SIZE) {
+		dev_err(ipc_mmio->dev, "Unexpected Chip Info");
+		goto init_fail;
+	}
+
+	ipc_mmio->offset.rom_exit_code = MMIO_OFFSET_ROM_EXIT_CODE;
+
+	ipc_mmio->offset.psi_address = MMIO_OFFSET_PSI_ADDRESS;
+	ipc_mmio->offset.psi_size = MMIO_OFFSET_PSI_SIZE;
+	ipc_mmio->offset.ipc_status = MMIO_OFFSET_IPC_STATUS;
+	ipc_mmio->offset.context_info = MMIO_OFFSET_CONTEXT_INFO;
+	ipc_mmio->offset.ap_win_base = MMIO_OFFSET_BASE_ADDR;
+	ipc_mmio->offset.ap_win_end = MMIO_OFFSET_END_ADDR;
+
+	ipc_mmio->offset.cp_version = MMIO_OFFSET_CP_VERSION;
+	ipc_mmio->offset.cp_capability = MMIO_OFFSET_CP_CAPABILITIES;
+
+	return ipc_mmio;
+
+init_fail:
+	kfree(ipc_mmio);
+	return NULL;
+}
+
+enum ipc_mem_exec_stage ipc_mmio_get_exec_stage(struct iosm_mmio *ipc_mmio)
+{
+	if (!ipc_mmio)
+		return IPC_MEM_EXEC_STAGE_INVALID;
+
+	return (enum ipc_mem_exec_stage)readl(ipc_mmio->base +
+					      ipc_mmio->offset.exec_stage);
+}
+
+void ipc_mmio_copy_chip_info(struct iosm_mmio *ipc_mmio, void *dest,
+			     size_t size)
+{
+	if (ipc_mmio && dest)
+		memcpy_fromio(dest, ipc_mmio->base + ipc_mmio->offset.chip_info,
+			      size);
+}
+
+enum ipc_mem_device_ipc_state ipc_mmio_get_ipc_state(struct iosm_mmio *ipc_mmio)
+{
+	if (!ipc_mmio)
+		return IPC_MEM_DEVICE_IPC_INVALID;
+
+	return (enum ipc_mem_device_ipc_state)
+		readl(ipc_mmio->base + ipc_mmio->offset.ipc_status);
+}
+
+enum rom_exit_code ipc_mmio_get_rom_exit_code(struct iosm_mmio *ipc_mmio)
+{
+	if (!ipc_mmio)
+		return IMEM_ROM_EXIT_FAIL;
+
+	return (enum rom_exit_code)readl(ipc_mmio->base +
+					 ipc_mmio->offset.rom_exit_code);
+}
+
+void ipc_mmio_config(struct iosm_mmio *ipc_mmio)
+{
+	if (!ipc_mmio)
+		return;
+
+	/* AP memory window (full window is open and active so that modem checks
+	 * each AP address) 0 means don't check on modem side.
+	 */
+	iowrite64_lo_hi(0, ipc_mmio->base + ipc_mmio->offset.ap_win_base);
+	iowrite64_lo_hi(0, ipc_mmio->base + ipc_mmio->offset.ap_win_end);
+
+	iowrite64_lo_hi(ipc_mmio->context_info_addr,
+			ipc_mmio->base + ipc_mmio->offset.context_info);
+}
+
+void ipc_mmio_set_psi_addr_and_size(struct iosm_mmio *ipc_mmio, dma_addr_t addr,
+				    u32 size)
+{
+	if (!ipc_mmio)
+		return;
+
+	iowrite64_lo_hi(addr, ipc_mmio->base + ipc_mmio->offset.psi_address);
+	writel(size, ipc_mmio->base + ipc_mmio->offset.psi_size);
+}
+
+void ipc_mmio_set_contex_info_addr(struct iosm_mmio *ipc_mmio, phys_addr_t addr)
+{
+	if (!ipc_mmio)
+		return;
+
+	/* store context_info address. This will be stored in the mmio area
+	 * during IPC_MEM_DEVICE_IPC_INIT state via ipc_mmio_config()
+	 */
+	ipc_mmio->context_info_addr = addr;
+}
+
+int ipc_mmio_get_cp_version(struct iosm_mmio *ipc_mmio)
+{
+	return ipc_mmio ? readl(ipc_mmio->base + ipc_mmio->offset.cp_version) :
+			  -EFAULT;
+}