GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

source/bootloader/u-boot-2020.01/arch/arm/cpu/armv7/syslib.c

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2008
+ * Texas Instruments, <www.ti.com>
+ *
+ * Richard Woodruff <r-woodruff2@ti.com>
+ * Syed Mohammed Khasim <khasim@ti.com>
+ */
+
+#include <common.h>
+#include <asm/io.h>
+
+/************************************************************
+ * sdelay() - simple spin loop.  Will be constant time as
+ *  its generally used in bypass conditions only.  This
+ *  is necessary until timers are accessible.
+ *
+ *  not inline to increase chances its in cache when called
+ *************************************************************/
+void sdelay(unsigned long loops)
+{
+	__asm__ volatile ("1:\n" "subs %0, %1, #1\n"
+			  "bne 1b":"=r" (loops):"0"(loops));
+}
+
+/*********************************************************************
+ * wait_on_value() - common routine to allow waiting for changes in
+ *   volatile regs.
+ *********************************************************************/
+u32 wait_on_value(u32 read_bit_mask, u32 match_value, void *read_addr,
+		  u32 bound)
+{
+	u32 i = 0, val;
+	do {
+		++i;
+		val = readl((u32)read_addr) & read_bit_mask;
+		if (val == match_value)
+			return 1;
+		if (i == bound)
+			return 0;
+	} while (1);
+}