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linux-next/arch/mips/kernel/vpe-mt.c
Ralf Baechle b633648c5a MIPS: MT: Remove SMTC support
Nobody is maintaining SMTC anymore and there also seems to be no userbase.
Which is a pity - the SMTC technology primarily developed by Kevin D.
Kissell <kevink@paralogos.com> is an ingenious demonstration for the MT
ASE's power and elegance.

Based on Markos Chandras <Markos.Chandras@imgtec.com> patch
https://patchwork.linux-mips.org/patch/6719/ which while very similar did
no longer apply cleanly when I tried to merge it plus some additional
post-SMTC cleanup - SMTC was a feature as tricky to remove as it was to
merge once upon a time.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-05-24 00:07:01 +02:00

522 lines
11 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2004, 2005 MIPS Technologies, Inc. All rights reserved.
* Copyright (C) 2013 Imagination Technologies Ltd.
*/
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <asm/mipsregs.h>
#include <asm/mipsmtregs.h>
#include <asm/mips_mt.h>
#include <asm/vpe.h>
static int major;
/* The number of TCs and VPEs physically available on the core */
static int hw_tcs, hw_vpes;
/* We are prepared so configure and start the VPE... */
int vpe_run(struct vpe *v)
{
unsigned long flags, val, dmt_flag;
struct vpe_notifications *notifier;
unsigned int vpeflags;
struct tc *t;
/* check we are the Master VPE */
local_irq_save(flags);
val = read_c0_vpeconf0();
if (!(val & VPECONF0_MVP)) {
pr_warn("VPE loader: only Master VPE's are able to config MT\n");
local_irq_restore(flags);
return -1;
}
dmt_flag = dmt();
vpeflags = dvpe();
if (list_empty(&v->tc)) {
evpe(vpeflags);
emt(dmt_flag);
local_irq_restore(flags);
pr_warn("VPE loader: No TC's associated with VPE %d\n",
v->minor);
return -ENOEXEC;
}
t = list_first_entry(&v->tc, struct tc, tc);
/* Put MVPE's into 'configuration state' */
set_c0_mvpcontrol(MVPCONTROL_VPC);
settc(t->index);
/* should check it is halted, and not activated */
if ((read_tc_c0_tcstatus() & TCSTATUS_A) ||
!(read_tc_c0_tchalt() & TCHALT_H)) {
evpe(vpeflags);
emt(dmt_flag);
local_irq_restore(flags);
pr_warn("VPE loader: TC %d is already active!\n",
t->index);
return -ENOEXEC;
}
/*
* Write the address we want it to start running from in the TCPC
* register.
*/
write_tc_c0_tcrestart((unsigned long)v->__start);
write_tc_c0_tccontext((unsigned long)0);
/*
* Mark the TC as activated, not interrupt exempt and not dynamically
* allocatable
*/
val = read_tc_c0_tcstatus();
val = (val & ~(TCSTATUS_DA | TCSTATUS_IXMT)) | TCSTATUS_A;
write_tc_c0_tcstatus(val);
write_tc_c0_tchalt(read_tc_c0_tchalt() & ~TCHALT_H);
/*
* The sde-kit passes 'memsize' to __start in $a3, so set something
* here... Or set $a3 to zero and define DFLT_STACK_SIZE and
* DFLT_HEAP_SIZE when you compile your program
*/
mttgpr(6, v->ntcs);
mttgpr(7, physical_memsize);
/* set up VPE1 */
/*
* bind the TC to VPE 1 as late as possible so we only have the final
* VPE registers to set up, and so an EJTAG probe can trigger on it
*/
write_tc_c0_tcbind((read_tc_c0_tcbind() & ~TCBIND_CURVPE) | 1);
write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~(VPECONF0_VPA));
back_to_back_c0_hazard();
/* Set up the XTC bit in vpeconf0 to point at our tc */
write_vpe_c0_vpeconf0((read_vpe_c0_vpeconf0() & ~(VPECONF0_XTC))
| (t->index << VPECONF0_XTC_SHIFT));
back_to_back_c0_hazard();
/* enable this VPE */
write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | VPECONF0_VPA);
/* clear out any left overs from a previous program */
write_vpe_c0_status(0);
write_vpe_c0_cause(0);
/* take system out of configuration state */
clear_c0_mvpcontrol(MVPCONTROL_VPC);
/*
* SMVP kernels manage VPE enable independently, but uniprocessor
* kernels need to turn it on, even if that wasn't the pre-dvpe() state.
*/
#ifdef CONFIG_SMP
evpe(vpeflags);
#else
evpe(EVPE_ENABLE);
#endif
emt(dmt_flag);
local_irq_restore(flags);
list_for_each_entry(notifier, &v->notify, list)
notifier->start(VPE_MODULE_MINOR);
return 0;
}
void cleanup_tc(struct tc *tc)
{
unsigned long flags;
unsigned int mtflags, vpflags;
int tmp;
local_irq_save(flags);
mtflags = dmt();
vpflags = dvpe();
/* Put MVPE's into 'configuration state' */
set_c0_mvpcontrol(MVPCONTROL_VPC);
settc(tc->index);
tmp = read_tc_c0_tcstatus();
/* mark not allocated and not dynamically allocatable */
tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
tmp |= TCSTATUS_IXMT; /* interrupt exempt */
write_tc_c0_tcstatus(tmp);
write_tc_c0_tchalt(TCHALT_H);
mips_ihb();
clear_c0_mvpcontrol(MVPCONTROL_VPC);
evpe(vpflags);
emt(mtflags);
local_irq_restore(flags);
}
/* module wrapper entry points */
/* give me a vpe */
void *vpe_alloc(void)
{
int i;
struct vpe *v;
/* find a vpe */
for (i = 1; i < MAX_VPES; i++) {
v = get_vpe(i);
if (v != NULL) {
v->state = VPE_STATE_INUSE;
return v;
}
}
return NULL;
}
EXPORT_SYMBOL(vpe_alloc);
/* start running from here */
int vpe_start(void *vpe, unsigned long start)
{
struct vpe *v = vpe;
v->__start = start;
return vpe_run(v);
}
EXPORT_SYMBOL(vpe_start);
/* halt it for now */
int vpe_stop(void *vpe)
{
struct vpe *v = vpe;
struct tc *t;
unsigned int evpe_flags;
evpe_flags = dvpe();
t = list_entry(v->tc.next, struct tc, tc);
if (t != NULL) {
settc(t->index);
write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~VPECONF0_VPA);
}
evpe(evpe_flags);
return 0;
}
EXPORT_SYMBOL(vpe_stop);
/* I've done with it thank you */
int vpe_free(void *vpe)
{
struct vpe *v = vpe;
struct tc *t;
unsigned int evpe_flags;
t = list_entry(v->tc.next, struct tc, tc);
if (t == NULL)
return -ENOEXEC;
evpe_flags = dvpe();
/* Put MVPE's into 'configuration state' */
set_c0_mvpcontrol(MVPCONTROL_VPC);
settc(t->index);
write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~VPECONF0_VPA);
/* halt the TC */
write_tc_c0_tchalt(TCHALT_H);
mips_ihb();
/* mark the TC unallocated */
write_tc_c0_tcstatus(read_tc_c0_tcstatus() & ~TCSTATUS_A);
v->state = VPE_STATE_UNUSED;
clear_c0_mvpcontrol(MVPCONTROL_VPC);
evpe(evpe_flags);
return 0;
}
EXPORT_SYMBOL(vpe_free);
static ssize_t store_kill(struct device *dev, struct device_attribute *attr,
const char *buf, size_t len)
{
struct vpe *vpe = get_vpe(aprp_cpu_index());
struct vpe_notifications *notifier;
list_for_each_entry(notifier, &vpe->notify, list)
notifier->stop(aprp_cpu_index());
release_progmem(vpe->load_addr);
cleanup_tc(get_tc(aprp_cpu_index()));
vpe_stop(vpe);
vpe_free(vpe);
return len;
}
static DEVICE_ATTR(kill, S_IWUSR, NULL, store_kill);
static ssize_t ntcs_show(struct device *cd, struct device_attribute *attr,
char *buf)
{
struct vpe *vpe = get_vpe(aprp_cpu_index());
return sprintf(buf, "%d\n", vpe->ntcs);
}
static ssize_t ntcs_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t len)
{
struct vpe *vpe = get_vpe(aprp_cpu_index());
unsigned long new;
int ret;
ret = kstrtoul(buf, 0, &new);
if (ret < 0)
return ret;
if (new == 0 || new > (hw_tcs - aprp_cpu_index()))
return -EINVAL;
vpe->ntcs = new;
return len;
}
static DEVICE_ATTR_RW(ntcs);
static struct attribute *vpe_attrs[] = {
&dev_attr_kill.attr,
&dev_attr_ntcs.attr,
NULL,
};
ATTRIBUTE_GROUPS(vpe);
static void vpe_device_release(struct device *cd)
{
kfree(cd);
}
static struct class vpe_class = {
.name = "vpe",
.owner = THIS_MODULE,
.dev_release = vpe_device_release,
.dev_groups = vpe_groups,
};
static struct device vpe_device;
int __init vpe_module_init(void)
{
unsigned int mtflags, vpflags;
unsigned long flags, val;
struct vpe *v = NULL;
struct tc *t;
int tc, err;
if (!cpu_has_mipsmt) {
pr_warn("VPE loader: not a MIPS MT capable processor\n");
return -ENODEV;
}
if (vpelimit == 0) {
pr_warn("No VPEs reserved for AP/SP, not initialize VPE loader\n"
"Pass maxvpes=<n> argument as kernel argument\n");
return -ENODEV;
}
if (aprp_cpu_index() == 0) {
pr_warn("No TCs reserved for AP/SP, not initialize VPE loader\n"
"Pass maxtcs=<n> argument as kernel argument\n");
return -ENODEV;
}
major = register_chrdev(0, VPE_MODULE_NAME, &vpe_fops);
if (major < 0) {
pr_warn("VPE loader: unable to register character device\n");
return major;
}
err = class_register(&vpe_class);
if (err) {
pr_err("vpe_class registration failed\n");
goto out_chrdev;
}
device_initialize(&vpe_device);
vpe_device.class = &vpe_class,
vpe_device.parent = NULL,
dev_set_name(&vpe_device, "vpe1");
vpe_device.devt = MKDEV(major, VPE_MODULE_MINOR);
err = device_add(&vpe_device);
if (err) {
pr_err("Adding vpe_device failed\n");
goto out_class;
}
local_irq_save(flags);
mtflags = dmt();
vpflags = dvpe();
/* Put MVPE's into 'configuration state' */
set_c0_mvpcontrol(MVPCONTROL_VPC);
val = read_c0_mvpconf0();
hw_tcs = (val & MVPCONF0_PTC) + 1;
hw_vpes = ((val & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
for (tc = aprp_cpu_index(); tc < hw_tcs; tc++) {
/*
* Must re-enable multithreading temporarily or in case we
* reschedule send IPIs or similar we might hang.
*/
clear_c0_mvpcontrol(MVPCONTROL_VPC);
evpe(vpflags);
emt(mtflags);
local_irq_restore(flags);
t = alloc_tc(tc);
if (!t) {
err = -ENOMEM;
goto out_dev;
}
local_irq_save(flags);
mtflags = dmt();
vpflags = dvpe();
set_c0_mvpcontrol(MVPCONTROL_VPC);
/* VPE's */
if (tc < hw_tcs) {
settc(tc);
v = alloc_vpe(tc);
if (v == NULL) {
pr_warn("VPE: unable to allocate VPE\n");
goto out_reenable;
}
v->ntcs = hw_tcs - aprp_cpu_index();
/* add the tc to the list of this vpe's tc's. */
list_add(&t->tc, &v->tc);
/* deactivate all but vpe0 */
if (tc >= aprp_cpu_index()) {
unsigned long tmp = read_vpe_c0_vpeconf0();
tmp &= ~VPECONF0_VPA;
/* master VPE */
tmp |= VPECONF0_MVP;
write_vpe_c0_vpeconf0(tmp);
}
/* disable multi-threading with TC's */
write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() &
~VPECONTROL_TE);
if (tc >= vpelimit) {
/*
* Set config to be the same as vpe0,
* particularly kseg0 coherency alg
*/
write_vpe_c0_config(read_c0_config());
}
}
/* TC's */
t->pvpe = v; /* set the parent vpe */
if (tc >= aprp_cpu_index()) {
unsigned long tmp;
settc(tc);
/*
* A TC that is bound to any other VPE gets bound to
* VPE0, ideally I'd like to make it homeless but it
* doesn't appear to let me bind a TC to a non-existent
* VPE. Which is perfectly reasonable.
*
* The (un)bound state is visible to an EJTAG probe so
* may notify GDB...
*/
tmp = read_tc_c0_tcbind();
if (tmp & TCBIND_CURVPE) {
/* tc is bound >vpe0 */
write_tc_c0_tcbind(tmp & ~TCBIND_CURVPE);
t->pvpe = get_vpe(0); /* set the parent vpe */
}
/* halt the TC */
write_tc_c0_tchalt(TCHALT_H);
mips_ihb();
tmp = read_tc_c0_tcstatus();
/* mark not activated and not dynamically allocatable */
tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
tmp |= TCSTATUS_IXMT; /* interrupt exempt */
write_tc_c0_tcstatus(tmp);
}
}
out_reenable:
/* release config state */
clear_c0_mvpcontrol(MVPCONTROL_VPC);
evpe(vpflags);
emt(mtflags);
local_irq_restore(flags);
return 0;
out_dev:
device_del(&vpe_device);
out_class:
class_unregister(&vpe_class);
out_chrdev:
unregister_chrdev(major, VPE_MODULE_NAME);
return err;
}
void __exit vpe_module_exit(void)
{
struct vpe *v, *n;
device_del(&vpe_device);
class_unregister(&vpe_class);
unregister_chrdev(major, VPE_MODULE_NAME);
/* No locking needed here */
list_for_each_entry_safe(v, n, &vpecontrol.vpe_list, list) {
if (v->state != VPE_STATE_UNUSED)
release_vpe(v);
}
}