linux_dsm_epyc7002/drivers/fsi/fsi-master.h
Benjamin Herrenschmidt a2e7da86cc fsi: Add mechanism to set the tSendDelay and tEchoDelay values
Those values control the amount of "dummy" clocks between commands and
between a command and its response.

This adds a way to configure them from sysfs (to be later extended to
defaults in the device-tree). The default remains 16 (the HW default).

This is only supported if the backend supports the new link_config()
callback to configure the generation of those delays.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
---
2018-07-12 11:59:13 +10:00

63 lines
2.3 KiB
C

/*
* FSI master definitions. These comprise the core <--> master interface,
* to allow the core to interact with the (hardware-specific) masters.
*
* Copyright (C) IBM Corporation 2016
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef DRIVERS_FSI_MASTER_H
#define DRIVERS_FSI_MASTER_H
#include <linux/device.h>
#define FSI_MASTER_FLAG_SWCLOCK 0x1
struct fsi_master {
struct device dev;
int idx;
int n_links;
int flags;
int (*read)(struct fsi_master *, int link, uint8_t id,
uint32_t addr, void *val, size_t size);
int (*write)(struct fsi_master *, int link, uint8_t id,
uint32_t addr, const void *val, size_t size);
int (*term)(struct fsi_master *, int link, uint8_t id);
int (*send_break)(struct fsi_master *, int link);
int (*link_enable)(struct fsi_master *, int link);
int (*link_config)(struct fsi_master *, int link,
u8 t_send_delay, u8 t_echo_delay);
};
#define dev_to_fsi_master(d) container_of(d, struct fsi_master, dev)
/**
* fsi_master registration & lifetime: the fsi_master_register() and
* fsi_master_unregister() functions will take ownership of the master, and
* ->dev in particular. The registration path performs a get_device(), which
* takes the first reference on the device. Similarly, the unregistration path
* performs a put_device(), which may well drop the last reference.
*
* This means that master implementations *may* need to hold their own
* reference (via get_device()) on master->dev. In particular, if the device's
* ->release callback frees the fsi_master, then fsi_master_unregister will
* invoke this free if no other reference is held.
*
* The same applies for the error path of fsi_master_register; if the call
* fails, dev->release will have been invoked.
*/
extern int fsi_master_register(struct fsi_master *master);
extern void fsi_master_unregister(struct fsi_master *master);
extern int fsi_master_rescan(struct fsi_master *master);
#endif /* DRIVERS_FSI_MASTER_H */