[ARM] pxa: Add PXA3 standby code hooked into the IRQ wake scheme

Wakeup sources on PXA3 are enabled at two levels.  First, the MFP
configuration has to be set to enable which edges a specific pin
will trigger a wakeup.  The pin also has to be routed to a functional
unit.  Lastly, the functional unit must be enabled as a wakeup source
in the appropriate AD*ER registers (AD2D0ER for standby resume.)

This doesn't fit well with the IRQ wake scheme - we currently do a
best effort conversion from IRQ numbers to functional unit wake enable
bits.  For instance, there's several USB client related enable bits but
there's no corresponding IRQs to determine which you'd want.  Conversely,
there's a single enable bit covering several functional units.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-pxa/pxa3xx.c

@@ -19,6 +19,7 @@
 #include <linux/pm.h>
 #include <linux/platform_device.h>
 #include <linux/irq.h>
+#include <linux/io.h>
 
 #include <asm/hardware.h>
 #include <asm/arch/pxa3xx-regs.h>
@@ -201,6 +202,225 @@ static struct clk pxa3xx_clks[] = {
 	PXA3xx_CKEN("MMCCLK", MMC3, 19500000, 0, &pxa3xx_device_mci3.dev),
 };
 
+#ifdef CONFIG_PM
+#define SLEEP_SAVE_SIZE	4
+
+#define ISRAM_START	0x5c000000
+#define ISRAM_SIZE	SZ_256K
+
+static void __iomem *sram;
+static unsigned long wakeup_src;
+
+static void pxa3xx_cpu_pm_save(unsigned long *sleep_save)
+{
+	pr_debug("PM: CKENA=%08x CKENB=%08x\n", CKENA, CKENB);
+
+	if (CKENA & (1 << CKEN_USBH)) {
+		printk(KERN_ERR "PM: USB host clock not stopped?\n");
+		CKENA &= ~(1 << CKEN_USBH);
+	}
+//	CKENA |= 1 << (CKEN_ISC & 31);
+
+	/*
+	 * Low power modes require the HSIO2 clock to be enabled.
+	 */
+	CKENB |= 1 << (CKEN_HSIO2 & 31);
+}
+
+static void pxa3xx_cpu_pm_restore(unsigned long *sleep_save)
+{
+	CKENB &= ~(1 << (CKEN_HSIO2 & 31));
+}
+
+/*
+ * Enter a standby mode (S0D1C2 or S0D2C2).  Upon wakeup, the dynamic
+ * memory controller has to be reinitialised, so we place some code
+ * in the SRAM to perform this function.
+ *
+ * We disable FIQs across the standby - otherwise, we might receive a
+ * FIQ while the SDRAM is unavailable.
+ */
+static void pxa3xx_cpu_standby(unsigned int pwrmode)
+{
+	extern const char pm_enter_standby_start[], pm_enter_standby_end[];
+	void (*fn)(unsigned int) = (void __force *)(sram + 0x8000);
+
+	memcpy_toio(sram + 0x8000, pm_enter_standby_start,
+		    pm_enter_standby_end - pm_enter_standby_start);
+
+	AD2D0SR = ~0;
+	AD2D1SR = ~0;
+	AD2D0ER = wakeup_src;
+	AD2D1ER = 0;
+	ASCR = ASCR;
+	ARSR = ARSR;
+
+	local_fiq_disable();
+	fn(pwrmode);
+	local_fiq_enable();
+
+	AD2D0ER = 0;
+	AD2D1ER = 0;
+
+	printk("PM: AD2D0SR=%08x ASCR=%08x\n", AD2D0SR, ASCR);
+}
+
+static void pxa3xx_cpu_pm_enter(suspend_state_t state)
+{
+	/*
+	 * Don't sleep if no wakeup sources are defined
+	 */
+	if (wakeup_src == 0)
+		return;
+
+	switch (state) {
+	case PM_SUSPEND_STANDBY:
+		pxa3xx_cpu_standby(PXA3xx_PM_S0D2C2);
+		break;
+
+	case PM_SUSPEND_MEM:
+		break;
+	}
+}
+
+static int pxa3xx_cpu_pm_valid(suspend_state_t state)
+{
+	return state == PM_SUSPEND_MEM || state == PM_SUSPEND_STANDBY;
+}
+
+static struct pxa_cpu_pm_fns pxa3xx_cpu_pm_fns = {
+	.save_size	= SLEEP_SAVE_SIZE,
+	.save		= pxa3xx_cpu_pm_save,
+	.restore	= pxa3xx_cpu_pm_restore,
+	.valid		= pxa3xx_cpu_pm_valid,
+	.enter		= pxa3xx_cpu_pm_enter,
+};
+
+static void __init pxa3xx_init_pm(void)
+{
+	sram = ioremap(ISRAM_START, ISRAM_SIZE);
+	if (!sram) {
+		printk(KERN_ERR "Unable to map ISRAM: disabling standby/suspend\n");
+		return;
+	}
+
+	/*
+	 * Since we copy wakeup code into the SRAM, we need to ensure
+	 * that it is preserved over the low power modes.  Note: bit 8
+	 * is undocumented in the developer manual, but must be set.
+	 */
+	AD1R |= ADXR_L2 | ADXR_R0;
+	AD2R |= ADXR_L2 | ADXR_R0;
+	AD3R |= ADXR_L2 | ADXR_R0;
+
+	/*
+	 * Clear the resume enable registers.
+	 */
+	AD1D0ER = 0;
+	AD2D0ER = 0;
+	AD2D1ER = 0;
+	AD3ER = 0;
+
+	pxa_cpu_pm_fns = &pxa3xx_cpu_pm_fns;
+}
+
+static int pxa3xx_set_wake(unsigned int irq, unsigned int on)
+{
+	unsigned long flags, mask = 0;
+
+	switch (irq) {
+	case IRQ_SSP3:
+		mask = ADXER_MFP_WSSP3;
+		break;
+	case IRQ_MSL:
+		mask = ADXER_WMSL0;
+		break;
+	case IRQ_USBH2:
+	case IRQ_USBH1:
+		mask = ADXER_WUSBH;
+		break;
+	case IRQ_KEYPAD:
+		mask = ADXER_WKP;
+		break;
+	case IRQ_AC97:
+		mask = ADXER_MFP_WAC97;
+		break;
+	case IRQ_USIM:
+		mask = ADXER_WUSIM0;
+		break;
+	case IRQ_SSP2:
+		mask = ADXER_MFP_WSSP2;
+		break;
+	case IRQ_I2C:
+		mask = ADXER_MFP_WI2C;
+		break;
+	case IRQ_STUART:
+		mask = ADXER_MFP_WUART3;
+		break;
+	case IRQ_BTUART:
+		mask = ADXER_MFP_WUART2;
+		break;
+	case IRQ_FFUART:
+		mask = ADXER_MFP_WUART1;
+		break;
+	case IRQ_MMC:
+		mask = ADXER_MFP_WMMC1;
+		break;
+	case IRQ_SSP:
+		mask = ADXER_MFP_WSSP1;
+		break;
+	case IRQ_RTCAlrm:
+		mask = ADXER_WRTC;
+		break;
+	case IRQ_SSP4:
+		mask = ADXER_MFP_WSSP4;
+		break;
+	case IRQ_TSI:
+		mask = ADXER_WTSI;
+		break;
+	case IRQ_USIM2:
+		mask = ADXER_WUSIM1;
+		break;
+	case IRQ_MMC2:
+		mask = ADXER_MFP_WMMC2;
+		break;
+	case IRQ_NAND:
+		mask = ADXER_MFP_WFLASH;
+		break;
+	case IRQ_USB2:
+		mask = ADXER_WUSB2;
+		break;
+	case IRQ_WAKEUP0:
+		mask = ADXER_WEXTWAKE0;
+		break;
+	case IRQ_WAKEUP1:
+		mask = ADXER_WEXTWAKE1;
+		break;
+	case IRQ_MMC3:
+		mask = ADXER_MFP_GEN12;
+		break;
+	}
+
+	local_irq_save(flags);
+	if (on)
+		wakeup_src |= mask;
+	else
+		wakeup_src &= ~mask;
+	local_irq_restore(flags);
+
+	return 0;
+}
+
+static void pxa3xx_init_irq_pm(void)
+{
+	pxa_init_irq_set_wake(pxa3xx_set_wake);
+}
+
+#else
+static inline void pxa3xx_init_pm(void) {}
+static inline void pxa3xx_init_irq_pm(void) {}
+#endif
+
 void __init pxa3xx_init_irq(void)
 {
 	/* enable CP6 access */
@@ -212,6 +432,7 @@ void __init pxa3xx_init_irq(void)
 	pxa_init_irq_low();
 	pxa_init_irq_high();
 	pxa_init_irq_gpio(128);
+	pxa3xx_init_irq_pm();
 }
 
 /*
@@ -241,6 +462,8 @@ static int __init pxa3xx_init(void)
 		if ((ret = pxa_init_dma(32)))
 			return ret;
 
+		pxa3xx_init_pm();
+
 		return platform_add_devices(devices, ARRAY_SIZE(devices));
 	}
 	return 0;

arch/arm/mach-pxa/standby.S

@@ -32,3 +32,83 @@ ENTRY(pxa_cpu_standby)
 	mov	pc, lr
 
 #endif
+
+#ifdef CONFIG_PXA3xx
+
+#define MDCNFG		0x0000
+#define MDCNFG_DMCEN	(1 << 30)
+#define DDR_HCAL	0x0060
+#define DDR_HCAL_HCRNG	0x1f
+#define DDR_HCAL_HCPROG	(1 << 28)
+#define DDR_HCAL_HCEN	(1 << 31)
+#define DMCIER		0x0070
+#define DMCIER_EDLP	(1 << 29)
+#define DMCISR		0x0078
+#define RCOMP		0x0100
+#define RCOMP_SWEVAL	(1 << 31)
+
+ENTRY(pm_enter_standby_start)
+	mov	r1, #0xf6000000		@ DMEMC_REG_BASE (MDCNFG)
+	add	r1, r1, #0x00100000
+
+	/*
+	 * Preload the TLB entry for accessing the dynamic memory
+	 * controller registers.  Note that page table lookups will
+	 * fail until the dynamic memory controller has been
+	 * reinitialised - and that includes MMU page table walks.
+	 * This also means that only the dynamic memory controller
+	 * can be reliably accessed in the code following standby.
+	 */
+	ldr	r2, [r1]		@ Dummy read MDCNFG
+
+	mcr	p14, 0, r0, c7, c0, 0
+	.rept	8
+	nop
+	.endr
+
+	ldr	r0, [r1, #DDR_HCAL]	@ Clear (and wait for) HCEN
+	bic	r0, r0, #DDR_HCAL_HCEN
+	str	r0, [r1, #DDR_HCAL]
+1:	ldr	r0, [r1, #DDR_HCAL]
+	tst	r0, #DDR_HCAL_HCEN
+	bne	1b
+
+	ldr	r0, [r1, #RCOMP]	@ Initiate RCOMP
+	orr	r0, r0, #RCOMP_SWEVAL
+	str	r0, [r1, #RCOMP]
+
+	mov	r0, #~0			@ Clear interrupts
+	str	r0, [r1, #DMCISR]
+
+	ldr	r0, [r1, #DMCIER]	@ set DMIER[EDLP]
+	orr	r0, r0, #DMCIER_EDLP
+	str	r0, [r1, #DMCIER]
+
+	ldr	r0, [r1, #DDR_HCAL]	@ clear HCRNG, set HCPROG, HCEN
+	bic	r0, r0, #DDR_HCAL_HCRNG
+	orr	r0, r0, #DDR_HCAL_HCEN | DDR_HCAL_HCPROG
+	str	r0, [r1, #DDR_HCAL]
+
+1:	ldr	r0, [r1, #DMCISR]
+	tst	r0, #DMCIER_EDLP
+	beq	1b
+
+	ldr	r0, [r1, #MDCNFG]	@ set MDCNFG[DMCEN]
+	orr	r0, r0, #MDCNFG_DMCEN
+	str	r0, [r1, #MDCNFG]
+1:	ldr	r0, [r1, #MDCNFG]
+	tst	r0, #MDCNFG_DMCEN
+	beq	1b
+
+	ldr	r0, [r1, #DDR_HCAL]	@ set DDR_HCAL[HCRNG]
+	orr	r0, r0, #2 @ HCRNG
+	str	r0, [r1, #DDR_HCAL]
+
+	ldr	r0, [r1, #DMCIER]	@ Clear the interrupt
+	bic	r0, r0, #0x20000000
+	str	r0, [r1, #DMCIER]
+
+	mov	pc, lr
+ENTRY(pm_enter_standby_end)
+
+#endif