[SPARC64]: Add hypervisor API negotiation and fix console bugs.
Hypervisor interfaces need to be negotiated in order to use
some API calls reliably. So add a small set of interfaces
to request API versions and query current settings.
This allows us to fix some bugs in the hypervisor console:
1) If we can negotiate API group CORE of at least major 1
minor 1 we can use con_read and con_write which can improve
console performance quite a bit.
2) When we do a console write request, we should hold the
spinlock around the whole request, not a byte at a time.
What would happen is that it's easy for output from
different cpus to get mixed with each other.
3) Use consistent udelay() based polling, udelay(1) each
loop with a limit of 1000 polls to handle stuck hypervisor
console.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc64/kernel/hvapi.c b/arch/sparc64/kernel/hvapi.c
new file mode 100644
index 0000000..f03ffc8
--- /dev/null
+++ b/arch/sparc64/kernel/hvapi.c
@@ -0,0 +1,189 @@
+/* hvapi.c: Hypervisor API management.
+ *
+ * Copyright (C) 2007 David S. Miller <davem@davemloft.net>
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+
+#include <asm/hypervisor.h>
+#include <asm/oplib.h>
+
+/* If the hypervisor indicates that the API setting
+ * calls are unsupported, by returning HV_EBADTRAP or
+ * HV_ENOTSUPPORTED, we assume that API groups with the
+ * PRE_API flag set are major 1 minor 0.
+ */
+struct api_info {
+ unsigned long group;
+ unsigned long major;
+ unsigned long minor;
+ unsigned int refcnt;
+ unsigned int flags;
+#define FLAG_PRE_API 0x00000001
+};
+
+static struct api_info api_table[] = {
+ { .group = HV_GRP_SUN4V, .flags = FLAG_PRE_API },
+ { .group = HV_GRP_CORE, .flags = FLAG_PRE_API },
+ { .group = HV_GRP_INTR, },
+ { .group = HV_GRP_SOFT_STATE, },
+ { .group = HV_GRP_PCI, .flags = FLAG_PRE_API },
+ { .group = HV_GRP_LDOM, },
+ { .group = HV_GRP_SVC_CHAN, .flags = FLAG_PRE_API },
+ { .group = HV_GRP_NCS, .flags = FLAG_PRE_API },
+ { .group = HV_GRP_NIAG_PERF, .flags = FLAG_PRE_API },
+ { .group = HV_GRP_FIRE_PERF, },
+ { .group = HV_GRP_DIAG, .flags = FLAG_PRE_API },
+};
+
+static DEFINE_SPINLOCK(hvapi_lock);
+
+static struct api_info *__get_info(unsigned long group)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(api_table); i++) {
+ if (api_table[i].group == group)
+ return &api_table[i];
+ }
+ return NULL;
+}
+
+static void __get_ref(struct api_info *p)
+{
+ p->refcnt++;
+}
+
+static void __put_ref(struct api_info *p)
+{
+ if (--p->refcnt == 0) {
+ unsigned long ignore;
+
+ sun4v_set_version(p->group, 0, 0, &ignore);
+ p->major = p->minor = 0;
+ }
+}
+
+/* Register a hypervisor API specification. It indicates the
+ * API group and desired major+minor.
+ *
+ * If an existing API registration exists '0' (success) will
+ * be returned if it is compatible with the one being registered.
+ * Otherwise a negative error code will be returned.
+ *
+ * Otherwise an attempt will be made to negotiate the requested
+ * API group/major/minor with the hypervisor, and errors returned
+ * if that does not succeed.
+ */
+int sun4v_hvapi_register(unsigned long group, unsigned long major,
+ unsigned long *minor)
+{
+ struct api_info *p;
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(&hvapi_lock, flags);
+ p = __get_info(group);
+ ret = -EINVAL;
+ if (p) {
+ if (p->refcnt) {
+ ret = -EINVAL;
+ if (p->major == major) {
+ *minor = p->minor;
+ ret = 0;
+ }
+ } else {
+ unsigned long actual_minor;
+ unsigned long hv_ret;
+
+ hv_ret = sun4v_set_version(group, major, *minor,
+ &actual_minor);
+ ret = -EINVAL;
+ if (hv_ret == HV_EOK) {
+ *minor = actual_minor;
+ p->major = major;
+ p->minor = actual_minor;
+ ret = 0;
+ } else if (hv_ret == HV_EBADTRAP ||
+ HV_ENOTSUPPORTED) {
+ if (p->flags & FLAG_PRE_API) {
+ if (major == 1) {
+ p->major = 1;
+ p->minor = 0;
+ *minor = 0;
+ ret = 0;
+ }
+ }
+ }
+ }
+
+ if (ret == 0)
+ __get_ref(p);
+ }
+ spin_unlock_irqrestore(&hvapi_lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL(sun4v_hvapi_register);
+
+void sun4v_hvapi_unregister(unsigned long group)
+{
+ struct api_info *p;
+ unsigned long flags;
+
+ spin_lock_irqsave(&hvapi_lock, flags);
+ p = __get_info(group);
+ if (p)
+ __put_ref(p);
+ spin_unlock_irqrestore(&hvapi_lock, flags);
+}
+EXPORT_SYMBOL(sun4v_hvapi_unregister);
+
+int sun4v_hvapi_get(unsigned long group,
+ unsigned long *major,
+ unsigned long *minor)
+{
+ struct api_info *p;
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(&hvapi_lock, flags);
+ ret = -EINVAL;
+ p = __get_info(group);
+ if (p && p->refcnt) {
+ *major = p->major;
+ *minor = p->minor;
+ ret = 0;
+ }
+ spin_unlock_irqrestore(&hvapi_lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL(sun4v_hvapi_get);
+
+void __init sun4v_hvapi_init(void)
+{
+ unsigned long group, major, minor;
+
+ group = HV_GRP_SUN4V;
+ major = 1;
+ minor = 0;
+ if (sun4v_hvapi_register(group, major, &minor))
+ goto bad;
+
+ group = HV_GRP_CORE;
+ major = 1;
+ minor = 1;
+ if (sun4v_hvapi_register(group, major, &minor))
+ goto bad;
+
+ return;
+
+bad:
+ prom_printf("HVAPI: Cannot register API group "
+ "%lx with major(%u) minor(%u)\n",
+ group, major, minor);
+ prom_halt();
+}