timer-nps.c
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/*
* Copyright (c) 2016, Mellanox Technologies. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include <linux/interrupt.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/clk.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/cpu.h>
#include <soc/nps/common.h>
#define NPS_MSU_TICK_LOW 0xC8
#define NPS_CLUSTER_OFFSET 8
#define NPS_CLUSTER_NUM 16
/* This array is per cluster of CPUs (Each NPS400 cluster got 256 CPUs) */
static void *nps_msu_reg_low_addr[NPS_CLUSTER_NUM] __read_mostly;
static unsigned long nps_timer_rate;
static cycle_t nps_clksrc_read(struct clocksource *clksrc)
{
int cluster = raw_smp_processor_id() >> NPS_CLUSTER_OFFSET;
return (cycle_t)ioread32be(nps_msu_reg_low_addr[cluster]);
}
static int __init nps_setup_clocksource(struct device_node *node,
struct clk *clk)
{
int ret, cluster;
for (cluster = 0; cluster < NPS_CLUSTER_NUM; cluster++)
nps_msu_reg_low_addr[cluster] =
nps_host_reg((cluster << NPS_CLUSTER_OFFSET),
NPS_MSU_BLKID, NPS_MSU_TICK_LOW);
ret = clk_prepare_enable(clk);
if (ret) {
pr_err("Couldn't enable parent clock\n");
return ret;
}
nps_timer_rate = clk_get_rate(clk);
ret = clocksource_mmio_init(nps_msu_reg_low_addr, "EZnps-tick",
nps_timer_rate, 301, 32, nps_clksrc_read);
if (ret) {
pr_err("Couldn't register clock source.\n");
clk_disable_unprepare(clk);
}
return ret;
}
static int __init nps_timer_init(struct device_node *node)
{
struct clk *clk;
clk = of_clk_get(node, 0);
if (IS_ERR(clk)) {
pr_err("Can't get timer clock.\n");
return PTR_ERR(clk);
}
return nps_setup_clocksource(node, clk);
}
CLOCKSOURCE_OF_DECLARE(ezchip_nps400_clksrc, "ezchip,nps400-timer",
nps_timer_init);