linux/drivers/soc/qcom/rpmh-internal.h
Douglas Anderson e40b0c1628 soc: qcom: rpmh-rsc: A lot of comments
I've been pouring through the rpmh-rsc code and trying to understand
it.  Document everything to the best of my ability.  All documentation
here is strictly from code analysis--no actual knowledge of the
hardware was used.  If something is wrong in here I either
misunderstood the code, had a typo, or the code has a bug in it
leading to my incorrect understanding.

In a few places here I have documented things that don't make tons of
sense.  A future patch will try to address this.  While this means I'm
adding comments / todos and then later fixing them in the series, it
seemed more urgent to get things documented first so that people could
understand the later patches.

Any comments I adjusted I also tried to make match kernel-doc better.
Specifically:
- kernel-doc says do not leave a blank line between the function
  description and the arguments
- kernel-doc examples always have things starting w/ a capital and
  ending with a period.

This should be a no-op.  It's just comment changes.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20200413100321.v4.6.I52653eb85d7dc8981ee0dafcd0b6cc0f273e9425@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
2020-04-13 22:09:35 -07:00

141 lines
4.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (c) 2016-2018, The Linux Foundation. All rights reserved.
*/
#ifndef __RPM_INTERNAL_H__
#define __RPM_INTERNAL_H__
#include <linux/bitmap.h>
#include <soc/qcom/tcs.h>
#define TCS_TYPE_NR 4
#define MAX_CMDS_PER_TCS 16
#define MAX_TCS_PER_TYPE 3
#define MAX_TCS_NR (MAX_TCS_PER_TYPE * TCS_TYPE_NR)
#define MAX_TCS_SLOTS (MAX_CMDS_PER_TCS * MAX_TCS_PER_TYPE)
struct rsc_drv;
/**
* struct tcs_group: group of Trigger Command Sets (TCS) to send state requests
* to the controller
*
* @drv: The controller.
* @type: Type of the TCS in this group - active, sleep, wake.
* @mask: Mask of the TCSes relative to all the TCSes in the RSC.
* @offset: Start of the TCS group relative to the TCSes in the RSC.
* @num_tcs: Number of TCSes in this type.
* @ncpt: Number of commands in each TCS.
* @lock: Lock for synchronizing this TCS writes.
* @req: Requests that are sent from the TCS; only used for ACTIVE_ONLY
* transfers (could be on a wake/sleep TCS if we are borrowing for
* an ACTIVE_ONLY transfer).
* Start: grab drv->lock, set req, set tcs_in_use, drop drv->lock,
* trigger
* End: get irq, access req,
* grab drv->lock, clear tcs_in_use, drop drv->lock
* @slots: Indicates which of @cmd_addr are occupied; only used for
* SLEEP / WAKE TCSs. Things are tightly packed in the
* case that (ncpt < MAX_CMDS_PER_TCS). That is if ncpt = 2 and
* MAX_CMDS_PER_TCS = 16 then bit[2] = the first bit in 2nd TCS.
*/
struct tcs_group {
struct rsc_drv *drv;
int type;
u32 mask;
u32 offset;
int num_tcs;
int ncpt;
spinlock_t lock;
const struct tcs_request *req[MAX_TCS_PER_TYPE];
DECLARE_BITMAP(slots, MAX_TCS_SLOTS);
};
/**
* struct rpmh_request: the message to be sent to rpmh-rsc
*
* @msg: the request
* @cmd: the payload that will be part of the @msg
* @completion: triggered when request is done
* @dev: the device making the request
* @err: err return from the controller
* @needs_free: check to free dynamically allocated request object
*/
struct rpmh_request {
struct tcs_request msg;
struct tcs_cmd cmd[MAX_RPMH_PAYLOAD];
struct completion *completion;
const struct device *dev;
int err;
bool needs_free;
};
/**
* struct rpmh_ctrlr: our representation of the controller
*
* @cache: the list of cached requests
* @cache_lock: synchronize access to the cache data
* @dirty: was the cache updated since flush
* @batch_cache: Cache sleep and wake requests sent as batch
*/
struct rpmh_ctrlr {
struct list_head cache;
spinlock_t cache_lock;
bool dirty;
struct list_head batch_cache;
};
/**
* struct rsc_drv: the Direct Resource Voter (DRV) of the
* Resource State Coordinator controller (RSC)
*
* @name: Controller identifier.
* @tcs_base: Start address of the TCS registers in this controller.
* @id: Instance id in the controller (Direct Resource Voter).
* @num_tcs: Number of TCSes in this DRV.
* @rsc_pm: CPU PM notifier for controller.
* Used when solver mode is not present.
* @cpus_entered_pm: CPU mask for cpus in idle power collapse.
* Used when solver mode is not present.
* @tcs: TCS groups.
* @tcs_in_use: S/W state of the TCS; only set for ACTIVE_ONLY
* transfers, but might show a sleep/wake TCS in use if
* it was borrowed for an active_only transfer. You
* must hold both the lock in this struct and the
* tcs_lock for the TCS in order to mark a TCS as
* in-use, but you only need the lock in this structure
* (aka the drv->lock) to mark one freed.
* @lock: Synchronize state of the controller. If you will be
* grabbing this lock and a tcs_lock at the same time,
* grab the tcs_lock first so we always have a
* consistent lock ordering.
* @pm_lock: Synchronize during PM notifications.
* Used when solver mode is not present.
* @client: Handle to the DRV's client.
*/
struct rsc_drv {
const char *name;
void __iomem *tcs_base;
int id;
int num_tcs;
struct notifier_block rsc_pm;
struct cpumask cpus_entered_pm;
struct tcs_group tcs[TCS_TYPE_NR];
DECLARE_BITMAP(tcs_in_use, MAX_TCS_NR);
spinlock_t lock;
spinlock_t pm_lock;
struct rpmh_ctrlr client;
};
int rpmh_rsc_send_data(struct rsc_drv *drv, const struct tcs_request *msg);
int rpmh_rsc_write_ctrl_data(struct rsc_drv *drv,
const struct tcs_request *msg);
int rpmh_rsc_invalidate(struct rsc_drv *drv);
void rpmh_tx_done(const struct tcs_request *msg, int r);
int rpmh_flush(struct rpmh_ctrlr *ctrlr);
#endif /* __RPM_INTERNAL_H__ */