xtensa: add xtensa arch oneshot ops

As xtensa timer is common in all xtensa chips,
Use oneshot ops, implement a common xtensa oneshot timer.

Signed-off-by: zhuyanlin <zhuyanlin1@xiaomi.com>

arch/xtensa/Kconfig

@@ -159,6 +159,13 @@ config XTENSA_DCACHE_LOCK
 	---help---
 		Enable Xtensa D-Cache lock & unlock feature
 
+config XTENSA_ONESHOT
+	bool "Xtensa oneshot lower half driver"
+	default n
+	depends on ONESHOT
+	---help---
+		Enable Xtensa oneshot driver.
+
 config ARCH_FAMILY_LX6
 	bool
 	default n

arch/xtensa/src/common/xtensa.h

@@ -318,6 +318,11 @@ void xtensa_add_region(void);
 # define xtensa_add_region()
 #endif
 
+/* Watchdog timer ***********************************************************/
+
+struct oneshot_lowerhalf_s *
+xtensa_oneshot_initialize(uint32_t irq, uint32_t freq);
+
 /* Serial output */
 
 void up_lowputc(char ch);

arch/xtensa/src/common/xtensa_oneshot.c

@@ -0,0 +1,200 @@
+/****************************************************************************
+ * arch/xtensa/src/common/xtensa_oneshot.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <assert.h>
+#include <nuttx/irq.h>
+#include <nuttx/kmalloc.h>
+#include <nuttx/timers/oneshot.h>
+
+#include "xtensa_counter.h"
+#include "xtensa.h"
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/* This structure provides the private representation of the "lower-half"
+ * driver state structure.  This structure must be cast-compatible with the
+ * oneshot_lowerhalf_s structure.
+ */
+
+struct xoneshot_lowerhalf_s
+{
+  struct oneshot_lowerhalf_s lh;       /* Lower half operations */
+  uint32_t                   freq;     /* Timer working clock frequency(Hz) */
+  oneshot_callback_t         callback; /* Current user interrupt callback */
+  void                      *arg;      /* Argument passed to upper half callback */
+  uint32_t                   irq;
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static int xtensa_oneshot_maxdelay(struct oneshot_lowerhalf_s *lower,
+                                   struct timespec *ts);
+static int xtensa_oneshot_start(struct oneshot_lowerhalf_s *lower,
+                                oneshot_callback_t callback, void *arg,
+                                const struct timespec *ts);
+static int xtensa_oneshot_cancel(struct oneshot_lowerhalf_s *lower,
+                                 struct timespec *ts);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct oneshot_operations_s g_xtensa_oneshot_ops =
+{
+  .max_delay = xtensa_oneshot_maxdelay,
+  .start     = xtensa_oneshot_start,
+  .cancel    = xtensa_oneshot_cancel,
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static inline uint64_t nsec_from_count(uint32_t count, uint32_t freq)
+{
+  return (uint64_t)count * NSEC_PER_SEC / freq;
+}
+
+static inline uint64_t nsec_to_count(uint32_t nsec, uint32_t freq)
+{
+  return (uint64_t)nsec * freq / NSEC_PER_SEC;
+}
+
+static inline uint64_t sec_to_count(uint32_t sec, uint32_t freq)
+{
+  return (uint64_t)sec * freq;
+}
+
+static int xtensa_oneshot_start(struct oneshot_lowerhalf_s *lower_,
+                                oneshot_callback_t callback, void *arg,
+                                const struct timespec *ts)
+{
+  struct xoneshot_lowerhalf_s *lower =
+    (struct xoneshot_lowerhalf_s *)lower_;
+  uint32_t count;
+  irqstate_t flags;
+
+  flags = enter_critical_section();
+
+  lower->callback = callback;
+  lower->arg      = arg;
+
+  count = sec_to_count((uint64_t)ts->tv_sec, lower->freq) +
+          nsec_to_count((uint64_t)ts->tv_nsec, lower->freq);
+
+  count = xtensa_getcount() + count;
+  xtensa_setcompare(count);
+
+  up_enable_irq(lower->irq);
+
+  leave_critical_section(flags);
+
+  return 0;
+}
+
+static int xtensa_oneshot_cancel(struct oneshot_lowerhalf_s *lower_,
+                                 struct timespec *ts)
+{
+  struct xoneshot_lowerhalf_s *lower =
+    (struct xoneshot_lowerhalf_s *)lower_;
+  irqstate_t flags;
+
+  flags = enter_critical_section();
+
+  lower->callback  = NULL;
+  lower->arg       = NULL;
+
+  up_disable_irq(lower->irq);
+
+  leave_critical_section(flags);
+
+  return 0;
+}
+
+static int xtensa_oneshot_maxdelay(struct oneshot_lowerhalf_s *lower_,
+                                   struct timespec *ts)
+{
+  struct xoneshot_lowerhalf_s *lower =
+    (struct xoneshot_lowerhalf_s *)lower_;
+
+  uint64_t maxnsec = nsec_from_count(UINT32_MAX, lower->freq);
+
+  ts->tv_sec  = maxnsec / NSEC_PER_SEC;
+  ts->tv_nsec = maxnsec % NSEC_PER_SEC;
+
+  return 0;
+}
+
+static int xtensa_oneshot_interrupt(int irq, void *context, void *arg)
+{
+  struct xoneshot_lowerhalf_s *lower = arg;
+  oneshot_callback_t callback;
+  void *cbarg;
+
+  DEBUGASSERT(lower != NULL);
+
+  if (lower->callback != NULL)
+    {
+      callback        = lower->callback;
+      cbarg           = lower->arg;
+      lower->callback = NULL;
+      lower->arg      = NULL;
+
+      /* Then perform the callback */
+
+      callback(&lower->lh, cbarg);
+    }
+
+  return 0;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+struct oneshot_lowerhalf_s *
+xtensa_oneshot_initialize(uint32_t irq, uint32_t freq)
+{
+  struct xoneshot_lowerhalf_s *lower =
+      (struct xoneshot_lowerhalf_s *)kmm_zalloc(sizeof(*lower));
+
+  if (lower == NULL)
+    {
+      return NULL;
+    }
+
+  lower->lh.ops = &g_xtensa_oneshot_ops;
+  lower->freq   = freq;
+  lower->irq    = irq;
+
+  irq_attach(irq, xtensa_oneshot_interrupt, lower);
+
+  return (struct oneshot_lowerhalf_s *)lower;
+}