initial import

tools/sdk/include/esp32/soc/cpu.h

@@ -0,0 +1,81 @@
+// Copyright 2010-2016 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed 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.
+
+#ifndef _SOC_CPU_H
+#define _SOC_CPU_H
+
+#include "xtensa/corebits.h"
+
+/* C macros for xtensa special register read/write/exchange */
+
+#define RSR(reg, curval)  asm volatile ("rsr %0, " #reg : "=r" (curval));
+#define WSR(reg, newval)  asm volatile ("wsr %0, " #reg : : "r" (newval));
+#define XSR(reg, swapval) asm volatile ("xsr %0, " #reg : "+r" (swapval));
+
+/* Return true if the CPU is in an interrupt context
+   (PS.UM == 0)
+*/
+static inline bool cpu_in_interrupt_context(void)
+{
+    uint32_t ps;
+    RSR(PS, ps);
+    return (ps & PS_UM) == 0;
+}
+
+/* Functions to set page attributes for Region Protection option in the CPU.
+ * See Xtensa ISA Reference manual for explanation of arguments (section 4.6.3.2).
+ */
+
+static inline void cpu_write_dtlb(uint32_t vpn, unsigned attr)
+{
+    asm volatile ("wdtlb  %1, %0; dsync\n" :: "r" (vpn), "r" (attr));
+}
+
+
+static inline void cpu_write_itlb(unsigned vpn, unsigned attr)
+{
+    asm volatile ("witlb  %1, %0; isync\n" :: "r" (vpn), "r" (attr));
+}
+
+/* Make page 0 access raise an exception.
+ * Also protect some other unused pages so we can catch weirdness.
+ * Useful attribute values:
+ * 0 — cached, RW
+ * 2 — bypass cache, RWX (default value after CPU reset)
+ * 15 — no access, raise exception
+ */
+
+static inline void cpu_configure_region_protection()
+{
+    const uint32_t pages_to_protect[] = {0x00000000, 0x80000000, 0xa0000000, 0xc0000000, 0xe0000000};
+    for (int i = 0; i < sizeof(pages_to_protect)/sizeof(pages_to_protect[0]); ++i) {
+        cpu_write_dtlb(pages_to_protect[i], 0xf);
+        cpu_write_itlb(pages_to_protect[i], 0xf);
+    }
+    cpu_write_dtlb(0x20000000, 0);
+    cpu_write_itlb(0x20000000, 0);
+}
+
+
+
+/*
+ * @brief Set CPU frequency to the value defined in menuconfig
+ *
+ * Called from cpu_start.c, not intended to be called from other places.
+ * This is a temporary function which will be replaced once dynamic
+ * CPU frequency changing is implemented.
+ */
+void esp_set_cpu_freq(void);
+
+#endif