From e02cda008591317b1625707ff8e115a4841aa889 Mon Sep 17 00:00:00 2001
From: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Date: Tue, 10 Oct 2023 11:40:56 +0000
Subject: Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9
---
 hw/openrisc/cputimer.c | 145 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 145 insertions(+)
 create mode 100644 hw/openrisc/cputimer.c

(limited to 'hw/openrisc/cputimer.c')

diff --git a/hw/openrisc/cputimer.c b/hw/openrisc/cputimer.c
new file mode 100644
index 000000000..93268815d
--- /dev/null
+++ b/hw/openrisc/cputimer.c
@@ -0,0 +1,145 @@
+/*
+ * QEMU OpenRISC timer support
+ *
+ * Copyright (c) 2011-2012 Jia Liu <proljc@gmail.com>
+ *                         Zhizhou Zhang <etouzh@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "cpu.h"
+#include "migration/vmstate.h"
+#include "qemu/timer.h"
+
+#define TIMER_PERIOD 50 /* 50 ns period for 20 MHz timer */
+
+/* Tick Timer global state to allow all cores to be in sync */
+typedef struct OR1KTimerState {
+    uint32_t ttcr;
+    uint64_t last_clk;
+} OR1KTimerState;
+
+static OR1KTimerState *or1k_timer;
+
+void cpu_openrisc_count_set(OpenRISCCPU *cpu, uint32_t val)
+{
+    or1k_timer->ttcr = val;
+}
+
+uint32_t cpu_openrisc_count_get(OpenRISCCPU *cpu)
+{
+    return or1k_timer->ttcr;
+}
+
+/* Add elapsed ticks to ttcr */
+void cpu_openrisc_count_update(OpenRISCCPU *cpu)
+{
+    uint64_t now;
+
+    if (!cpu->env.is_counting) {
+        return;
+    }
+    now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+    or1k_timer->ttcr += (uint32_t)((now - or1k_timer->last_clk)
+                                    / TIMER_PERIOD);
+    or1k_timer->last_clk = now;
+}
+
+/* Update the next timeout time as difference between ttmr and ttcr */
+void cpu_openrisc_timer_update(OpenRISCCPU *cpu)
+{
+    uint32_t wait;
+    uint64_t now, next;
+
+    if (!cpu->env.is_counting) {
+        return;
+    }
+
+    cpu_openrisc_count_update(cpu);
+    now = or1k_timer->last_clk;
+
+    if ((cpu->env.ttmr & TTMR_TP) <= (or1k_timer->ttcr & TTMR_TP)) {
+        wait = TTMR_TP - (or1k_timer->ttcr & TTMR_TP) + 1;
+        wait += cpu->env.ttmr & TTMR_TP;
+    } else {
+        wait = (cpu->env.ttmr & TTMR_TP) - (or1k_timer->ttcr & TTMR_TP);
+    }
+    next = now + (uint64_t)wait * TIMER_PERIOD;
+    timer_mod(cpu->env.timer, next);
+}
+
+void cpu_openrisc_count_start(OpenRISCCPU *cpu)
+{
+    cpu->env.is_counting = 1;
+    cpu_openrisc_count_update(cpu);
+}
+
+void cpu_openrisc_count_stop(OpenRISCCPU *cpu)
+{
+    timer_del(cpu->env.timer);
+    cpu_openrisc_count_update(cpu);
+    cpu->env.is_counting = 0;
+}
+
+static void openrisc_timer_cb(void *opaque)
+{
+    OpenRISCCPU *cpu = opaque;
+
+    if ((cpu->env.ttmr & TTMR_IE) &&
+         timer_expired(cpu->env.timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL))) {
+        CPUState *cs = CPU(cpu);
+
+        cpu->env.ttmr |= TTMR_IP;
+        cs->interrupt_request |= CPU_INTERRUPT_TIMER;
+    }
+
+    switch (cpu->env.ttmr & TTMR_M) {
+    case TIMER_NONE:
+        break;
+    case TIMER_INTR:
+        or1k_timer->ttcr = 0;
+        break;
+    case TIMER_SHOT:
+        cpu_openrisc_count_stop(cpu);
+        break;
+    case TIMER_CONT:
+        break;
+    }
+
+    cpu_openrisc_timer_update(cpu);
+    qemu_cpu_kick(CPU(cpu));
+}
+
+static const VMStateDescription vmstate_or1k_timer = {
+    .name = "or1k_timer",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(ttcr, OR1KTimerState),
+        VMSTATE_UINT64(last_clk, OR1KTimerState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+void cpu_openrisc_clock_init(OpenRISCCPU *cpu)
+{
+    cpu->env.timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &openrisc_timer_cb, cpu);
+    cpu->env.ttmr = 0x00000000;
+
+    if (or1k_timer == NULL) {
+        or1k_timer = g_new0(OR1KTimerState, 1);
+        vmstate_register(NULL, 0, &vmstate_or1k_timer, or1k_timer);
+    }
+}
-- 
cgit