2021-06-08 17:08:25

by M Chetan Kumar

[permalink] [raw]
Subject: [PATCH V4 11/16] net: iosm: power management

Implements state machine to handle host & device sleep.

Signed-off-by: M Chetan Kumar <[email protected]>
---
v4: no change.
v3: Aligned ipc_ prefix for function name to be consistent across file.
v2:
* Removed space around the : for the bitfields.
* Moved pm module under static allocation
* Added memory barriers around atomic operations.
---
drivers/net/wwan/iosm/iosm_ipc_pm.c | 333 ++++++++++++++++++++++++++++
drivers/net/wwan/iosm/iosm_ipc_pm.h | 207 +++++++++++++++++
2 files changed, 540 insertions(+)
create mode 100644 drivers/net/wwan/iosm/iosm_ipc_pm.c
create mode 100644 drivers/net/wwan/iosm/iosm_ipc_pm.h

diff --git a/drivers/net/wwan/iosm/iosm_ipc_pm.c b/drivers/net/wwan/iosm/iosm_ipc_pm.c
new file mode 100644
index 000000000000..413601c72dcd
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_pm.c
@@ -0,0 +1,333 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020-21 Intel Corporation.
+ */
+
+#include "iosm_ipc_protocol.h"
+
+/* Timeout value in MS for the PM to wait for device to reach active state */
+#define IPC_PM_ACTIVE_TIMEOUT_MS (500)
+
+/* Note that here "active" has the value 1, as compared to the enums
+ * ipc_mem_host_pm_state or ipc_mem_dev_pm_state, where "active" is 0
+ */
+#define IPC_PM_SLEEP (0)
+#define CONSUME_STATE (0)
+#define IPC_PM_ACTIVE (1)
+
+void ipc_pm_signal_hpda_doorbell(struct iosm_pm *ipc_pm, u32 identifier,
+ bool host_slp_check)
+{
+ if (host_slp_check && ipc_pm->host_pm_state != IPC_MEM_HOST_PM_ACTIVE &&
+ ipc_pm->host_pm_state != IPC_MEM_HOST_PM_ACTIVE_WAIT) {
+ ipc_pm->pending_hpda_update = true;
+ dev_dbg(ipc_pm->dev,
+ "Pend HPDA update set. Host PM_State: %d identifier:%d",
+ ipc_pm->host_pm_state, identifier);
+ return;
+ }
+
+ if (!ipc_pm_trigger(ipc_pm, IPC_PM_UNIT_IRQ, true)) {
+ ipc_pm->pending_hpda_update = true;
+ dev_dbg(ipc_pm->dev, "Pending HPDA update set. identifier:%d",
+ identifier);
+ return;
+ }
+ ipc_pm->pending_hpda_update = false;
+
+ /* Trigger the irq towards CP */
+ ipc_cp_irq_hpda_update(ipc_pm->pcie, identifier);
+
+ ipc_pm_trigger(ipc_pm, IPC_PM_UNIT_IRQ, false);
+}
+
+/* Wake up the device if it is in low power mode. */
+static bool ipc_pm_link_activate(struct iosm_pm *ipc_pm)
+{
+ if (ipc_pm->cp_state == IPC_MEM_DEV_PM_ACTIVE)
+ return true;
+
+ if (ipc_pm->cp_state == IPC_MEM_DEV_PM_SLEEP) {
+ if (ipc_pm->ap_state == IPC_MEM_DEV_PM_SLEEP) {
+ /* Wake up the device. */
+ ipc_cp_irq_sleep_control(ipc_pm->pcie,
+ IPC_MEM_DEV_PM_WAKEUP);
+ ipc_pm->ap_state = IPC_MEM_DEV_PM_ACTIVE_WAIT;
+
+ goto not_active;
+ }
+
+ if (ipc_pm->ap_state == IPC_MEM_DEV_PM_ACTIVE_WAIT)
+ goto not_active;
+
+ return true;
+ }
+
+not_active:
+ /* link is not ready */
+ return false;
+}
+
+bool ipc_pm_wait_for_device_active(struct iosm_pm *ipc_pm)
+{
+ bool ret_val = false;
+
+ if (ipc_pm->ap_state != IPC_MEM_DEV_PM_ACTIVE) {
+ /* Complete all memory stores before setting bit */
+ smp_mb__before_atomic();
+
+ /* Wait for IPC_PM_ACTIVE_TIMEOUT_MS for Device sleep state
+ * machine to enter ACTIVE state.
+ */
+ set_bit(0, &ipc_pm->host_sleep_pend);
+
+ /* Complete all memory stores after setting bit */
+ smp_mb__after_atomic();
+
+ if (!wait_for_completion_interruptible_timeout
+ (&ipc_pm->host_sleep_complete,
+ msecs_to_jiffies(IPC_PM_ACTIVE_TIMEOUT_MS))) {
+ dev_err(ipc_pm->dev,
+ "PM timeout. Expected State:%d. Actual: %d",
+ IPC_MEM_DEV_PM_ACTIVE, ipc_pm->ap_state);
+ goto active_timeout;
+ }
+ }
+
+ ret_val = true;
+active_timeout:
+ /* Complete all memory stores before clearing bit */
+ smp_mb__before_atomic();
+
+ /* Reset the atomic variable in any case as device sleep
+ * state machine change is no longer of interest.
+ */
+ clear_bit(0, &ipc_pm->host_sleep_pend);
+
+ /* Complete all memory stores after clearing bit */
+ smp_mb__after_atomic();
+
+ return ret_val;
+}
+
+static void ipc_pm_on_link_sleep(struct iosm_pm *ipc_pm)
+{
+ /* pending sleep ack and all conditions are cleared
+ * -> signal SLEEP__ACK to CP
+ */
+ ipc_pm->cp_state = IPC_MEM_DEV_PM_SLEEP;
+ ipc_pm->ap_state = IPC_MEM_DEV_PM_SLEEP;
+
+ ipc_cp_irq_sleep_control(ipc_pm->pcie, IPC_MEM_DEV_PM_SLEEP);
+}
+
+static void ipc_pm_on_link_wake(struct iosm_pm *ipc_pm, bool ack)
+{
+ ipc_pm->ap_state = IPC_MEM_DEV_PM_ACTIVE;
+
+ if (ack) {
+ ipc_pm->cp_state = IPC_MEM_DEV_PM_ACTIVE;
+
+ ipc_cp_irq_sleep_control(ipc_pm->pcie, IPC_MEM_DEV_PM_ACTIVE);
+
+ /* check the consume state !!! */
+ if (test_bit(CONSUME_STATE, &ipc_pm->host_sleep_pend))
+ complete(&ipc_pm->host_sleep_complete);
+ }
+
+ /* Check for pending HPDA update.
+ * Pending HP update could be because of sending message was
+ * put on hold due to Device sleep state or due to TD update
+ * which could be because of Device Sleep and Host Sleep
+ * states.
+ */
+ if (ipc_pm->pending_hpda_update &&
+ ipc_pm->host_pm_state == IPC_MEM_HOST_PM_ACTIVE)
+ ipc_pm_signal_hpda_doorbell(ipc_pm, IPC_HP_PM_TRIGGER, true);
+}
+
+bool ipc_pm_trigger(struct iosm_pm *ipc_pm, enum ipc_pm_unit unit, bool active)
+{
+ union ipc_pm_cond old_cond;
+ union ipc_pm_cond new_cond;
+ bool link_active;
+
+ /* Save the current D3 state. */
+ new_cond = ipc_pm->pm_cond;
+ old_cond = ipc_pm->pm_cond;
+
+ /* Calculate the power state only in the runtime phase. */
+ switch (unit) {
+ case IPC_PM_UNIT_IRQ: /* CP irq */
+ new_cond.irq = active;
+ break;
+
+ case IPC_PM_UNIT_LINK: /* Device link state. */
+ new_cond.link = active;
+ break;
+
+ case IPC_PM_UNIT_HS: /* Host sleep trigger requires Link. */
+ new_cond.hs = active;
+ break;
+
+ default:
+ break;
+ }
+
+ /* Something changed ? */
+ if (old_cond.raw == new_cond.raw) {
+ /* Stay in the current PM state. */
+ link_active = old_cond.link == IPC_PM_ACTIVE;
+ goto ret;
+ }
+
+ ipc_pm->pm_cond = new_cond;
+
+ if (new_cond.link)
+ ipc_pm_on_link_wake(ipc_pm, unit == IPC_PM_UNIT_LINK);
+ else if (unit == IPC_PM_UNIT_LINK)
+ ipc_pm_on_link_sleep(ipc_pm);
+
+ if (old_cond.link == IPC_PM_SLEEP && new_cond.raw) {
+ link_active = ipc_pm_link_activate(ipc_pm);
+ goto ret;
+ }
+
+ link_active = old_cond.link == IPC_PM_ACTIVE;
+
+ret:
+ return link_active;
+}
+
+bool ipc_pm_prepare_host_sleep(struct iosm_pm *ipc_pm)
+{
+ /* suspend not allowed if host_pm_state is not IPC_MEM_HOST_PM_ACTIVE */
+ if (ipc_pm->host_pm_state != IPC_MEM_HOST_PM_ACTIVE) {
+ dev_err(ipc_pm->dev, "host_pm_state=%d\tExpected to be: %d",
+ ipc_pm->host_pm_state, IPC_MEM_HOST_PM_ACTIVE);
+ return false;
+ }
+
+ ipc_pm->host_pm_state = IPC_MEM_HOST_PM_SLEEP_WAIT_D3;
+
+ return true;
+}
+
+bool ipc_pm_prepare_host_active(struct iosm_pm *ipc_pm)
+{
+ if (ipc_pm->host_pm_state != IPC_MEM_HOST_PM_SLEEP) {
+ dev_err(ipc_pm->dev, "host_pm_state=%d\tExpected to be: %d",
+ ipc_pm->host_pm_state, IPC_MEM_HOST_PM_SLEEP);
+ return false;
+ }
+
+ /* Sending Sleep Exit message to CP. Update the state */
+ ipc_pm->host_pm_state = IPC_MEM_HOST_PM_ACTIVE_WAIT;
+
+ return true;
+}
+
+void ipc_pm_set_s2idle_sleep(struct iosm_pm *ipc_pm, bool sleep)
+{
+ if (sleep) {
+ ipc_pm->ap_state = IPC_MEM_DEV_PM_SLEEP;
+ ipc_pm->cp_state = IPC_MEM_DEV_PM_SLEEP;
+ ipc_pm->device_sleep_notification = IPC_MEM_DEV_PM_SLEEP;
+ } else {
+ ipc_pm->ap_state = IPC_MEM_DEV_PM_ACTIVE;
+ ipc_pm->cp_state = IPC_MEM_DEV_PM_ACTIVE;
+ ipc_pm->device_sleep_notification = IPC_MEM_DEV_PM_ACTIVE;
+ ipc_pm->pm_cond.link = IPC_PM_ACTIVE;
+ }
+}
+
+bool ipc_pm_dev_slp_notification(struct iosm_pm *ipc_pm, u32 cp_pm_req)
+{
+ if (cp_pm_req == ipc_pm->device_sleep_notification)
+ return false;
+
+ ipc_pm->device_sleep_notification = cp_pm_req;
+
+ /* Evaluate the PM request. */
+ switch (ipc_pm->cp_state) {
+ case IPC_MEM_DEV_PM_ACTIVE:
+ switch (cp_pm_req) {
+ case IPC_MEM_DEV_PM_ACTIVE:
+ break;
+
+ case IPC_MEM_DEV_PM_SLEEP:
+ /* Inform the PM that the device link can go down. */
+ ipc_pm_trigger(ipc_pm, IPC_PM_UNIT_LINK, false);
+ return true;
+
+ default:
+ dev_err(ipc_pm->dev,
+ "loc-pm=%d active: confused req-pm=%d",
+ ipc_pm->cp_state, cp_pm_req);
+ break;
+ }
+ break;
+
+ case IPC_MEM_DEV_PM_SLEEP:
+ switch (cp_pm_req) {
+ case IPC_MEM_DEV_PM_ACTIVE:
+ /* Inform the PM that the device link is active. */
+ ipc_pm_trigger(ipc_pm, IPC_PM_UNIT_LINK, true);
+ break;
+
+ case IPC_MEM_DEV_PM_SLEEP:
+ break;
+
+ default:
+ dev_err(ipc_pm->dev,
+ "loc-pm=%d sleep: confused req-pm=%d",
+ ipc_pm->cp_state, cp_pm_req);
+ break;
+ }
+ break;
+
+ default:
+ dev_err(ipc_pm->dev, "confused loc-pm=%d, req-pm=%d",
+ ipc_pm->cp_state, cp_pm_req);
+ break;
+ }
+
+ return false;
+}
+
+void ipc_pm_init(struct iosm_protocol *ipc_protocol)
+{
+ struct iosm_imem *ipc_imem = ipc_protocol->imem;
+ struct iosm_pm *ipc_pm = &ipc_protocol->pm;
+
+ ipc_pm->pcie = ipc_imem->pcie;
+ ipc_pm->dev = ipc_imem->dev;
+
+ ipc_pm->pm_cond.irq = IPC_PM_SLEEP;
+ ipc_pm->pm_cond.hs = IPC_PM_SLEEP;
+ ipc_pm->pm_cond.link = IPC_PM_ACTIVE;
+
+ ipc_pm->cp_state = IPC_MEM_DEV_PM_ACTIVE;
+ ipc_pm->ap_state = IPC_MEM_DEV_PM_ACTIVE;
+ ipc_pm->host_pm_state = IPC_MEM_HOST_PM_ACTIVE;
+
+ /* Create generic wait-for-completion handler for Host Sleep
+ * and device sleep coordination.
+ */
+ init_completion(&ipc_pm->host_sleep_complete);
+
+ /* Complete all memory stores before clearing bit */
+ smp_mb__before_atomic();
+
+ clear_bit(0, &ipc_pm->host_sleep_pend);
+
+ /* Complete all memory stores after clearing bit */
+ smp_mb__after_atomic();
+}
+
+void ipc_pm_deinit(struct iosm_protocol *proto)
+{
+ struct iosm_pm *ipc_pm = &proto->pm;
+
+ complete(&ipc_pm->host_sleep_complete);
+}
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
--
2.25.1