1 files changed, 523 insertions, 0 deletions
diff --git a/arch/mips/kernel/vpe-mt.c b/arch/mips/kernel/vpe-mt.c
new file mode 100644
index 000000000000..949ae0e17018
--- /dev/null
+++ b/arch/mips/kernel/vpe-mt.c
@@ -0,0 +1,523 @@
+/*
+ * 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);
+
+	/*
+	 * SMTC/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);
+
+			/* Any TC that is bound to VPE0 gets left as is - in
+			 * case we are running SMTC on VPE0. 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);
+	}
+}