linux/arch/arc/plat-eznps/mtm.c

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/*
* Copyright(c) 2015 EZchip Technologies.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*
* The full GNU General Public License is included in this distribution in
* the file called "COPYING".
*/
#include <linux/smp.h>
#include <linux/io.h>
#include <linux/log2.h>
#include <asm/arcregs.h>
#include <plat/mtm.h>
#include <plat/smp.h>
#define MT_CTRL_HS_CNT 0xFF
#define MT_CTRL_ST_CNT 0xF
#define NPS_NUM_HW_THREADS 0x10
static void mtm_init_nat(int cpu)
{
struct nps_host_reg_mtm_cfg mtm_cfg;
struct nps_host_reg_aux_udmc udmc;
int log_nat, nat = 0, i, t;
/* Iterate core threads and update nat */
for (i = 0, t = cpu; i < NPS_NUM_HW_THREADS; i++, t++)
nat += test_bit(t, cpumask_bits(cpu_possible_mask));
log_nat = ilog2(nat);
udmc.value = read_aux_reg(CTOP_AUX_UDMC);
udmc.nat = log_nat;
write_aux_reg(CTOP_AUX_UDMC, udmc.value);
mtm_cfg.value = ioread32be(MTM_CFG(cpu));
mtm_cfg.nat = log_nat;
iowrite32be(mtm_cfg.value, MTM_CFG(cpu));
}
static void mtm_init_thread(int cpu)
{
int i, tries = 5;
struct nps_host_reg_thr_init thr_init;
struct nps_host_reg_thr_init_sts thr_init_sts;
/* Set thread init register */
thr_init.value = 0;
iowrite32be(thr_init.value, MTM_THR_INIT(cpu));
thr_init.thr_id = NPS_CPU_TO_THREAD_NUM(cpu);
thr_init.str = 1;
iowrite32be(thr_init.value, MTM_THR_INIT(cpu));
/* Poll till thread init is done */
for (i = 0; i < tries; i++) {
thr_init_sts.value = ioread32be(MTM_THR_INIT_STS(cpu));
if (thr_init_sts.thr_id == thr_init.thr_id) {
if (thr_init_sts.bsy)
continue;
else if (thr_init_sts.err)
pr_warn("Failed to thread init cpu %u\n", cpu);
break;
}
pr_warn("Wrong thread id in thread init for cpu %u\n", cpu);
break;
}
if (i == tries)
pr_warn("Got thread init timeout for cpu %u\n", cpu);
}
int mtm_enable_thread(int cpu)
{
struct nps_host_reg_mtm_cfg mtm_cfg;
if (NPS_CPU_TO_THREAD_NUM(cpu) == 0)
return 1;
/* Enable thread in mtm */
mtm_cfg.value = ioread32be(MTM_CFG(cpu));
mtm_cfg.ten |= (1 << (NPS_CPU_TO_THREAD_NUM(cpu)));
iowrite32be(mtm_cfg.value, MTM_CFG(cpu));
return 0;
}
void mtm_enable_core(unsigned int cpu)
{
int i;
struct nps_host_reg_aux_mt_ctrl mt_ctrl;
struct nps_host_reg_mtm_cfg mtm_cfg;
if (NPS_CPU_TO_THREAD_NUM(cpu) != 0)
return;
/* Initialize Number of Active Threads */
mtm_init_nat(cpu);
/* Initialize mtm_cfg */
mtm_cfg.value = ioread32be(MTM_CFG(cpu));
mtm_cfg.ten = 1;
iowrite32be(mtm_cfg.value, MTM_CFG(cpu));
/* Initialize all other threads in core */
for (i = 1; i < NPS_NUM_HW_THREADS; i++)
mtm_init_thread(cpu + i);
/* Enable HW schedule, stall counter, mtm */
mt_ctrl.value = 0;
mt_ctrl.hsen = 1;
mt_ctrl.hs_cnt = MT_CTRL_HS_CNT;
mt_ctrl.sten = 1;
mt_ctrl.st_cnt = MT_CTRL_ST_CNT;
mt_ctrl.mten = 1;
write_aux_reg(CTOP_AUX_MT_CTRL, mt_ctrl.value);
/*
* HW scheduling mechanism will start working
* Only after call to instruction "schd.rw".
* cpu_relax() calls "schd.rw" instruction.
*/
cpu_relax();
}