tty: Add Haven RM Console driver

Haven Resource Manager API defines a simple console for VM log sharing.
This patch adds support for this console with the HVC console framework.
It is possible to use this driver as the "primary VM" to listen to other
VM console logs or as the "secondary VM" to send logs to the "primary
VM". For the latter, CONFIG_HVC_HAVEN_CONSOLE must be set to y.

Change-Id: I3606b2d373535d0f347f66e5b729a303a9513fa8
Signed-off-by: Elliot Berman <[email protected]>

drivers/tty/hvc/Kconfig

@@ -87,6 +87,25 @@ config HVC_DCC
 	 driver. This console is used through a JTAG only on ARM. If you don't have
 	 a JTAG then you probably don't want this option.
 
+config HVC_HAVEN
+	tristate "Haven tty support"
+	depends on HH_RM_DRV
+	select HVC_DRIVER
+	help
+	  This console exposes communication with other
+	  virtual machines in the Haven hypervisor. This
+	  option may also be used as an early console
+	  to another VM.
+
+config HVC_HAVEN_CONSOLE
+	bool "Haven console support"
+	depends on HVC_HAVEN
+	help
+	  Select this option to allow Haven tty
+	  as an boot console communicating with
+	  the primary VM. Still need to specify
+	  earlycon and console parameters.
+
 config HVC_RISCV_SBI
 	bool "RISC-V SBI console support"
 	depends on RISCV

drivers/tty/hvc/Makefile

@@ -4,6 +4,7 @@ obj-$(CONFIG_HVC_OPAL)		+= hvc_opal.o hvsi_lib.o
 obj-$(CONFIG_HVC_OLD_HVSI)	+= hvsi.o
 obj-$(CONFIG_HVC_RTAS)		+= hvc_rtas.o
 obj-$(CONFIG_HVC_DCC)		+= hvc_dcc.o
+obj-$(CONFIG_HVC_HAVEN)	+= hvc_haven.o
 obj-$(CONFIG_HVC_DRIVER)	+= hvc_console.o
 obj-$(CONFIG_HVC_IRQ)		+= hvc_irq.o
 obj-$(CONFIG_HVC_XEN)		+= hvc_xen.o

drivers/tty/hvc/hvc_haven.c

@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2020, The Linux Foundation. All rights reserved.
+ */
+
+#define pr_fmt(fmt) "hvc_haven: " fmt
+
+#include <linux/console.h>
+#include <linux/init.h>
+#include <linux/kfifo.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/spinlock.h>
+#include <linux/printk.h>
+
+#include <linux/haven/hh_common.h>
+#include <linux/haven/hh_rm_drv.h>
+
+#include "hvc_console.h"
+
+#define HVC_HH_VTERM_COOKIE	0x474E5948
+
+struct hh_hvc_prv {
+	struct hvc_struct *hvc;
+	DECLARE_KFIFO(fifo, char, 1024);
+};
+
+static DEFINE_SPINLOCK(fifo_lock);
+static struct hh_hvc_prv hh_hvc_data[2];
+
+static inline int hh_vm_name_to_vtermno(enum hh_vm_names vmname)
+{
+	return vmname + HVC_HH_VTERM_COOKIE;
+}
+
+static inline int vtermno_to_hh_vm_name(int vtermno)
+{
+	return vtermno - HVC_HH_VTERM_COOKIE;
+}
+
+static int hh_hvc_notify_console_chars(struct notifier_block *this,
+				       unsigned long cmd, void *data)
+{
+	struct hh_rm_notif_vm_console_chars *msg = data;
+	enum hh_vm_names vm_name;
+	int ret;
+
+	if (cmd != HH_RM_NOTIF_VM_CONSOLE_CHARS)
+		return NOTIFY_DONE;
+
+	ret = hh_rm_get_vm_name(msg->vmid, &vm_name);
+	if (ret) {
+		pr_warn_ratelimited("don't know VMID %d\n", vm_name);
+		return NOTIFY_OK;
+	}
+
+	ret = kfifo_in_spinlocked(&hh_hvc_data[vm_name].fifo,
+				  msg->bytes, msg->num_bytes,
+				  &fifo_lock);
+
+	if (ret < 0)
+		pr_warn_ratelimited("dropped %d bytes from VM%d - error %d\n",
+				    msg->num_bytes, vm_name, ret);
+	else if (ret < msg->num_bytes)
+		pr_warn_ratelimited("dropped %d bytes from VM%d - full fifo\n",
+				    msg->num_bytes - ret, vm_name);
+
+	hvc_kick();
+	return NOTIFY_OK;
+}
+
+static int hh_hvc_get_chars(uint32_t vtermno, char *buf, int count)
+{
+	int vm_name = vtermno_to_hh_vm_name(vtermno);
+
+	if (vm_name < 0 || vm_name >= HH_VM_MAX)
+		return -EINVAL;
+
+	return kfifo_out_spinlocked(&hh_hvc_data[vm_name].fifo,
+				    buf, count, &fifo_lock);
+}
+
+static int hh_hvc_put_chars(uint32_t vtermno, const char *buf, int count)
+{
+	int ret, vm_name = vtermno_to_hh_vm_name(vtermno);
+	hh_vmid_t vmid;
+
+	if (vm_name < 0 || vm_name >= HH_VM_MAX)
+		return -EINVAL;
+
+	ret = hh_rm_get_vmid(vm_name, &vmid);
+	if (ret)
+		return ret;
+
+
+	return hh_rm_console_write(vmid, buf, count);
+}
+
+static int hh_hvc_flush(uint32_t vtermno, bool wait)
+{
+	int ret, vm_name = vtermno_to_hh_vm_name(vtermno);
+	hh_vmid_t vmid;
+
+	if (vm_name < 0 || vm_name >= HH_VM_MAX)
+		return -EINVAL;
+
+	ret = hh_rm_get_vmid(vm_name, &vmid);
+	if (ret)
+		return ret;
+
+	return hh_rm_console_flush(vmid);
+}
+
+static int hh_hvc_notify_add(struct hvc_struct *hp, int vm_name)
+{
+	int ret;
+	hh_vmid_t vmid;
+
+	ret = hh_rm_get_vmid(vm_name, &vmid);
+	if (ret)
+		return ret;
+
+	return hh_rm_console_open(vmid);
+}
+
+static void hh_hvc_notify_del(struct hvc_struct *hp, int vm_name)
+{
+	int ret;
+	hh_vmid_t vmid;
+
+	if (vm_name < 0 || vm_name >= HH_VM_MAX)
+		return;
+
+	ret = hh_rm_get_vmid(vm_name, &vmid);
+	if (ret)
+		return;
+
+	ret = hh_rm_console_close(vmid);
+
+	if (ret)
+		pr_err("Failed close VM%d console - %d\n", vm_name, ret);
+
+	kfifo_reset(&hh_hvc_data[vm_name].fifo);
+}
+
+static struct notifier_block hh_hvc_nb = {
+	.notifier_call = hh_hvc_notify_console_chars,
+};
+
+static const struct hv_ops hh_hv_ops = {
+	.get_chars = hh_hvc_get_chars,
+	.put_chars = hh_hvc_put_chars,
+	.flush = hh_hvc_flush,
+	.notifier_add = hh_hvc_notify_add,
+	.notifier_del = hh_hvc_notify_del,
+};
+
+#ifdef CONFIG_HVC_HAVEN_CONSOLE
+static int __init hvc_hh_console_init(void)
+{
+	int ret;
+
+	ret = hvc_instantiate(hh_vm_name_to_vtermno(HH_PRIMARY_VM), 0,
+			      &hh_hv_ops);
+
+	return ret < 0 ? -ENODEV : 0;
+}
+console_initcall(hvc_hh_console_init);
+#endif /* CONFIG_HVC_HAVEN_CONSOLE */
+
+static int __init hvc_hh_init(void)
+{
+	int i, ret = 0;
+	struct hh_hvc_prv *prv;
+
+	for (i = 0; i < HH_VM_MAX; i++) {
+		prv = &hh_hvc_data[i];
+		INIT_KFIFO(prv->fifo);
+		prv->hvc = hvc_alloc(hh_vm_name_to_vtermno(i), i, &hh_hv_ops,
+				     256);
+		ret = PTR_ERR_OR_ZERO(prv->hvc);
+		if (ret)
+			goto bail;
+	}
+
+	ret = hh_rm_register_notifier(&hh_hvc_nb);
+	if (ret)
+		goto bail;
+
+	return 0;
+bail:
+	for (; i >= 0; i--) {
+		hvc_remove(hh_hvc_data[i].hvc);
+		hh_hvc_data[i].hvc = NULL;
+	}
+	return ret;
+}
+device_initcall(hvc_hh_init);
+
+static __exit void hvc_hh_exit(void)
+{
+	int i;
+
+	for (i = 0; i < HH_VM_MAX; i++)
+		if (hh_hvc_data[i].hvc) {
+			hvc_remove(hh_hvc_data[i].hvc);
+			hh_hvc_data[i].hvc = NULL;
+		}
+
+	hh_rm_unregister_notifier(&hh_hvc_nb);
+}
+module_exit(hvc_hh_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Qualcomm Technologies, Inc. Haven Hypervisor Console Driver");