1 files changed, 135 insertions, 0 deletions
diff --git a/arch/arm/mach-lpc32xx/pm.c b/arch/arm/mach-lpc32xx/pm.c
new file mode 100644
index 000000000..2572bd89a
--- /dev/null
+++ b/arch/arm/mach-lpc32xx/pm.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * arch/arm/mach-lpc32xx/pm.c
+ *
+ * Original authors: Vitaly Wool, Dmitry Chigirev <source@mvista.com>
+ * Modified by Kevin Wells <kevin.wells@nxp.com>
+ *
+ * 2005 (c) MontaVista Software, Inc.
+ */
+
+/*
+ * LPC32XX CPU and system power management
+ *
+ * The LPC32XX has three CPU modes for controlling system power: run,
+ * direct-run, and halt modes. When switching between halt and run modes,
+ * the CPU transistions through direct-run mode. For Linux, direct-run
+ * mode is not used in normal operation. Halt mode is used when the
+ * system is fully suspended.
+ *
+ * Run mode:
+ * The ARM CPU clock (HCLK_PLL), HCLK bus clock, and PCLK bus clocks are
+ * derived from the HCLK PLL. The HCLK and PCLK bus rates are divided from
+ * the HCLK_PLL rate. Linux runs in this mode.
+ *
+ * Direct-run mode:
+ * The ARM CPU clock, HCLK bus clock, and PCLK bus clocks are driven from
+ * SYSCLK. SYSCLK is usually around 13MHz, but may vary based on SYSCLK
+ * source or the frequency of the main oscillator. In this mode, the
+ * HCLK_PLL can be safely enabled, changed, or disabled.
+ *
+ * Halt mode:
+ * SYSCLK is gated off and the CPU and system clocks are halted.
+ * Peripherals based on the 32KHz oscillator clock (ie, RTC, touch,
+ * key scanner, etc.) still operate if enabled. In this state, an enabled
+ * system event (ie, GPIO state change, RTC match, key press, etc.) will
+ * wake the system up back into direct-run mode.
+ *
+ * DRAM refresh
+ * DRAM clocking and refresh are slightly different for systems with DDR
+ * DRAM or regular SDRAM devices. If SDRAM is used in the system, the
+ * SDRAM will still be accessible in direct-run mode. In DDR based systems,
+ * a transition to direct-run mode will stop all DDR accesses (no clocks).
+ * Because of this, the code to switch power modes and the code to enter
+ * and exit DRAM self-refresh modes must not be executed in DRAM. A small
+ * section of IRAM is used instead for this.
+ *
+ * Suspend is handled with the following logic:
+ *  Backup a small area of IRAM used for the suspend code
+ *  Copy suspend code to IRAM
+ *  Transfer control to code in IRAM
+ *  Places DRAMs in self-refresh mode
+ *  Enter direct-run mode
+ *  Save state of HCLK_PLL PLL
+ *  Disable HCLK_PLL PLL
+ *  Enter halt mode - CPU and buses will stop
+ *  System enters direct-run mode when an enabled event occurs
+ *  HCLK PLL state is restored
+ *  Run mode is entered
+ *  DRAMS are placed back into normal mode
+ *  Code execution returns from IRAM
+ *  IRAM code are used for suspend is restored
+ *  Suspend mode is exited
+ */
+
+#include <linux/suspend.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+
+#include <asm/cacheflush.h>
+
+#include "lpc32xx.h"
+#include "common.h"
+
+#define TEMP_IRAM_AREA  IO_ADDRESS(LPC32XX_IRAM_BASE)
+
+/*
+ * Both STANDBY and MEM suspend states are handled the same with no
+ * loss of CPU or memory state
+ */
+static int lpc32xx_pm_enter(suspend_state_t state)
+{
+	int (*lpc32xx_suspend_ptr) (void);
+	void *iram_swap_area;
+
+	/* Allocate some space for temporary IRAM storage */
+	iram_swap_area = kmemdup((void *)TEMP_IRAM_AREA,
+				 lpc32xx_sys_suspend_sz, GFP_KERNEL);
+	if (!iram_swap_area)
+		return -ENOMEM;
+
+	/*
+	 * Copy code to suspend system into IRAM. The suspend code
+	 * needs to run from IRAM as DRAM may no longer be available
+	 * when the PLL is stopped.
+	 */
+	memcpy((void *) TEMP_IRAM_AREA, &lpc32xx_sys_suspend,
+		lpc32xx_sys_suspend_sz);
+	flush_icache_range((unsigned long)TEMP_IRAM_AREA,
+		(unsigned long)(TEMP_IRAM_AREA) + lpc32xx_sys_suspend_sz);
+
+	/* Transfer to suspend code in IRAM */
+	lpc32xx_suspend_ptr = (void *) TEMP_IRAM_AREA;
+	flush_cache_all();
+	(void) lpc32xx_suspend_ptr();
+
+	/* Restore original IRAM contents */
+	memcpy((void *) TEMP_IRAM_AREA, iram_swap_area,
+		lpc32xx_sys_suspend_sz);
+
+	kfree(iram_swap_area);
+
+	return 0;
+}
+
+static const struct platform_suspend_ops lpc32xx_pm_ops = {
+	.valid	= suspend_valid_only_mem,
+	.enter	= lpc32xx_pm_enter,
+};
+
+#define EMC_DYN_MEM_CTRL_OFS 0x20
+#define EMC_SRMMC           (1 << 3)
+#define EMC_CTRL_REG io_p2v(LPC32XX_EMC_BASE + EMC_DYN_MEM_CTRL_OFS)
+static int __init lpc32xx_pm_init(void)
+{
+	/*
+	 * Setup SDRAM self-refresh clock to automatically disable o
+	 * start of self-refresh. This only needs to be done once.
+	 */
+	__raw_writel(__raw_readl(EMC_CTRL_REG) | EMC_SRMMC, EMC_CTRL_REG);
+
+	suspend_set_ops(&lpc32xx_pm_ops);
+
+	return 0;
+}
+arch_initcall(lpc32xx_pm_init);