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, 207 insertions, 0 deletions

diff --git a/drivers/net/wwan/iosm/iosm_ipc_pm.h b/drivers/net/wwan/iosm/iosm_ipc_pm.h
new file mode 100644
index 000000000000..e7c00f388cb0
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_pm.h
@@ -0,0 +1,207 @@
+/* SPDX-License-Identifier: GPL-2.0-only
+ *
+ * Copyright (C) 2020-21 Intel Corporation.
+ */
+
+#ifndef IOSM_IPC_PM_H
+#define IOSM_IPC_PM_H
+
+/* Trigger the doorbell interrupt on cp to change the PM sleep/active status */
+#define ipc_cp_irq_sleep_control(ipc_pcie, data)                               \
+	ipc_doorbell_fire(ipc_pcie, IPC_DOORBELL_IRQ_SLEEP, data)
+
+/* Trigger the doorbell interrupt on CP to do hpda update */
+#define ipc_cp_irq_hpda_update(ipc_pcie, data)                                 \
+	ipc_doorbell_fire(ipc_pcie, IPC_DOORBELL_IRQ_HPDA, 0xFF & (data))
+
+/**
+ * union ipc_pm_cond - Conditions for D3 and the sleep message to CP.
+ * @raw:	raw/combined value for faster check
+ * @irq:	IRQ towards CP
+ * @hs:		Host Sleep
+ * @link:	Device link state.
+ */
+union ipc_pm_cond {
+	unsigned int raw;
+
+	struct {
+		unsigned int irq:1,
+			     hs:1,
+			     link:1;
+	};
+};
+
+/**
+ * enum ipc_mem_host_pm_state - Possible states of the HOST SLEEP finite state
+ *				machine.
+ * @IPC_MEM_HOST_PM_ACTIVE:		   Host is active
+ * @IPC_MEM_HOST_PM_ACTIVE_WAIT:	   Intermediate state before going to
+ *					   active
+ * @IPC_MEM_HOST_PM_SLEEP_WAIT_IDLE:	   Intermediate state to wait for idle
+ *					   before going into sleep
+ * @IPC_MEM_HOST_PM_SLEEP_WAIT_D3:	   Intermediate state to wait for D3
+ *					   before going to sleep
+ * @IPC_MEM_HOST_PM_SLEEP:		   after this state the interface is not
+ *					   accessible host is in suspend to RAM
+ * @IPC_MEM_HOST_PM_SLEEP_WAIT_EXIT_SLEEP: Intermediate state before exiting
+ *					   sleep
+ */
+enum ipc_mem_host_pm_state {
+	IPC_MEM_HOST_PM_ACTIVE,
+	IPC_MEM_HOST_PM_ACTIVE_WAIT,
+	IPC_MEM_HOST_PM_SLEEP_WAIT_IDLE,
+	IPC_MEM_HOST_PM_SLEEP_WAIT_D3,
+	IPC_MEM_HOST_PM_SLEEP,
+	IPC_MEM_HOST_PM_SLEEP_WAIT_EXIT_SLEEP,
+};
+
+/**
+ * enum ipc_mem_dev_pm_state - Possible states of the DEVICE SLEEP finite state
+ *			       machine.
+ * @IPC_MEM_DEV_PM_ACTIVE:		IPC_MEM_DEV_PM_ACTIVE is the initial
+ *					power management state.
+ *					IRQ(struct ipc_mem_device_info:
+ *					device_sleep_notification)
+ *					and DOORBELL-IRQ-HPDA(data) values.
+ * @IPC_MEM_DEV_PM_SLEEP:		IPC_MEM_DEV_PM_SLEEP is PM state for
+ *					sleep.
+ * @IPC_MEM_DEV_PM_WAKEUP:		DOORBELL-IRQ-DEVICE_WAKE(data).
+ * @IPC_MEM_DEV_PM_HOST_SLEEP:		DOORBELL-IRQ-HOST_SLEEP(data).
+ * @IPC_MEM_DEV_PM_ACTIVE_WAIT:		Local intermediate states.
+ * @IPC_MEM_DEV_PM_FORCE_SLEEP:		DOORBELL-IRQ-FORCE_SLEEP.
+ * @IPC_MEM_DEV_PM_FORCE_ACTIVE:	DOORBELL-IRQ-FORCE_ACTIVE.
+ */
+enum ipc_mem_dev_pm_state {
+	IPC_MEM_DEV_PM_ACTIVE,
+	IPC_MEM_DEV_PM_SLEEP,
+	IPC_MEM_DEV_PM_WAKEUP,
+	IPC_MEM_DEV_PM_HOST_SLEEP,
+	IPC_MEM_DEV_PM_ACTIVE_WAIT,
+	IPC_MEM_DEV_PM_FORCE_SLEEP = 7,
+	IPC_MEM_DEV_PM_FORCE_ACTIVE,
+};
+
+/**
+ * struct iosm_pm - Power management instance
+ * @pcie:			Pointer to iosm_pcie structure
+ * @dev:			Pointer to device structure
+ * @host_pm_state:		PM states for host
+ * @host_sleep_pend:		Variable to indicate Host Sleep Pending
+ * @host_sleep_complete:	Generic wait-for-completion used in
+ *				case of Host Sleep
+ * @pm_cond:			Conditions for power management
+ * @ap_state:			Current power management state, the
+ *				initial state is IPC_MEM_DEV_PM_ACTIVE eq. 0.
+ * @cp_state:			PM State of CP
+ * @device_sleep_notification:	last handled device_sleep_notfication
+ * @pending_hpda_update:	is a HPDA update pending?
+ */
+struct iosm_pm {
+	struct iosm_pcie *pcie;
+	struct device *dev;
+	enum ipc_mem_host_pm_state host_pm_state;
+	unsigned long host_sleep_pend;
+	struct completion host_sleep_complete;
+	union ipc_pm_cond pm_cond;
+	enum ipc_mem_dev_pm_state ap_state;
+	enum ipc_mem_dev_pm_state cp_state;
+	u32 device_sleep_notification;
+	u8 pending_hpda_update:1;
+};
+
+/**
+ * enum ipc_pm_unit - Power management units.
+ * @IPC_PM_UNIT_IRQ:	IRQ towards CP
+ * @IPC_PM_UNIT_HS:	Host Sleep for converged protocol
+ * @IPC_PM_UNIT_LINK:	Link state controlled by CP.
+ */
+enum ipc_pm_unit {
+	IPC_PM_UNIT_IRQ,
+	IPC_PM_UNIT_HS,
+	IPC_PM_UNIT_LINK,
+};
+
+/**
+ * ipc_pm_init - Allocate power management component
+ * @ipc_protocol:	Pointer to iosm_protocol structure
+ */
+void ipc_pm_init(struct iosm_protocol *ipc_protocol);
+
+/**
+ * ipc_pm_deinit - Free power management component, invalidating its pointer.
+ * @ipc_protocol:	Pointer to iosm_protocol structure
+ */
+void ipc_pm_deinit(struct iosm_protocol *ipc_protocol);
+
+/**
+ * ipc_pm_dev_slp_notification - Handle a sleep notification message from the
+ *				 device. This can be called from interrupt state
+ *				 This function handles Host Sleep requests too
+ *				 if the Host Sleep protocol is register based.
+ * @ipc_pm:			Pointer to power management component
+ * @sleep_notification:		Actual notification from device
+ *
+ * Returns: true if dev sleep state has to be checked, false otherwise.
+ */
+bool ipc_pm_dev_slp_notification(struct iosm_pm *ipc_pm,
+				 u32 sleep_notification);
+
+/**
+ * ipc_pm_set_s2idle_sleep - Set PM variables to sleep/active
+ * @ipc_pm:	Pointer to power management component
+ * @sleep:	true to enter sleep/false to exit sleep
+ */
+void ipc_pm_set_s2idle_sleep(struct iosm_pm *ipc_pm, bool sleep);
+
+/**
+ * ipc_pm_prepare_host_sleep - Prepare the PM for sleep by entering
+ *			       IPC_MEM_HOST_PM_SLEEP_WAIT_D3 state.
+ * @ipc_pm:	Pointer to power management component
+ *
+ * Returns: true on success, false if the host was not active.
+ */
+bool ipc_pm_prepare_host_sleep(struct iosm_pm *ipc_pm);
+
+/**
+ * ipc_pm_prepare_host_active - Prepare the PM for wakeup by entering
+ *				IPC_MEM_HOST_PM_ACTIVE_WAIT state.
+ * @ipc_pm:	Pointer to power management component
+ *
+ * Returns: true on success, false if the host was not sleeping.
+ */
+bool ipc_pm_prepare_host_active(struct iosm_pm *ipc_pm);
+
+/**
+ * ipc_pm_wait_for_device_active - Wait upto IPC_PM_ACTIVE_TIMEOUT_MS ms
+ *				   for the device to reach active state
+ * @ipc_pm:	Pointer to power management component
+ *
+ * Returns: true if device is active, false on timeout
+ */
+bool ipc_pm_wait_for_device_active(struct iosm_pm *ipc_pm);
+
+/**
+ * ipc_pm_signal_hpda_doorbell - Wake up the device if it is in low power mode
+ *				 and trigger a head pointer update interrupt.
+ * @ipc_pm:		Pointer to power management component
+ * @identifier:		specifies what component triggered hpda update irq
+ * @host_slp_check:	if set to true then Host Sleep state machine check will
+ *			be performed. If Host Sleep state machine allows HP
+ *			update then only doorbell is triggered otherwise pending
+ *			flag will be set. If set to false then Host Sleep check
+ *			will not be performed. This is helpful for Host Sleep
+ *			negotiation through message ring.
+ */
+void ipc_pm_signal_hpda_doorbell(struct iosm_pm *ipc_pm, u32 identifier,
+				 bool host_slp_check);
+/**
+ * ipc_pm_trigger - Update power manager and wake up the link if needed
+ * @ipc_pm:	Pointer to power management component
+ * @unit:	Power management units
+ * @active:	Device link state
+ *
+ * Returns: true if link is unchanged or active, false otherwise
+ */
+bool ipc_pm_trigger(struct iosm_pm *ipc_pm, enum ipc_pm_unit unit, bool active);
+
+#endif