d48866fefd
There is a defect in imx6 LPM design. When SW tries to enter low power mode with following sequence, the chip will enter low power mode before A9 CPU execute WFI instruction: 1. Set CCM_CLPCR[1:0] to 2'b00; 2. ARM CPU enters WFI; 3. ARM CPU wakeup from an interrupt event, which is masked by GPC or not visible to GPC, such as interrupt from local timer; 4. Set CCM_CLPCR[1:0] to 2'b01 or 2'b10; 5. ARM CPU execute WFI. Before the last step, the chip will enter WAIT mode if CCM_CLPCR[1:0] is set to 2'b01, or enter STOP mode if CCM_CLPCR[1:0] is set to 2'b10. The patch implements a recommended workaround for this issue. 1. SW triggers irq #32(IOMUX) to be always pending manually by setting IOMUX_GPR1_GINT bit; 2. SW should then unmask it in GPC before setting CCM LPM; 3. SW should mask it right after CCM LPM is set (bit0-1 of CCM_CLPCR). Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
140 lines
3.1 KiB
C
140 lines
3.1 KiB
C
/*
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* Copyright 2011-2013 Freescale Semiconductor, Inc.
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* Copyright 2011 Linaro Ltd.
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*
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* The code contained herein is licensed under the GNU General Public
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* License. You may obtain a copy of the GNU General Public License
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* Version 2 or later at the following locations:
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*
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* http://www.opensource.org/licenses/gpl-license.html
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* http://www.gnu.org/copyleft/gpl.html
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*/
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#include <linux/io.h>
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#include <linux/irq.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <linux/irqchip/arm-gic.h>
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#include "common.h"
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#define GPC_IMR1 0x008
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#define GPC_PGC_CPU_PDN 0x2a0
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#define IMR_NUM 4
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static void __iomem *gpc_base;
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static u32 gpc_wake_irqs[IMR_NUM];
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static u32 gpc_saved_imrs[IMR_NUM];
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void imx_gpc_pre_suspend(void)
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{
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void __iomem *reg_imr1 = gpc_base + GPC_IMR1;
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int i;
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/* Tell GPC to power off ARM core when suspend */
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writel_relaxed(0x1, gpc_base + GPC_PGC_CPU_PDN);
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for (i = 0; i < IMR_NUM; i++) {
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gpc_saved_imrs[i] = readl_relaxed(reg_imr1 + i * 4);
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writel_relaxed(~gpc_wake_irqs[i], reg_imr1 + i * 4);
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}
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}
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void imx_gpc_post_resume(void)
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{
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void __iomem *reg_imr1 = gpc_base + GPC_IMR1;
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int i;
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/* Keep ARM core powered on for other low-power modes */
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writel_relaxed(0x0, gpc_base + GPC_PGC_CPU_PDN);
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for (i = 0; i < IMR_NUM; i++)
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writel_relaxed(gpc_saved_imrs[i], reg_imr1 + i * 4);
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}
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static int imx_gpc_irq_set_wake(struct irq_data *d, unsigned int on)
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{
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unsigned int idx = d->irq / 32 - 1;
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u32 mask;
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/* Sanity check for SPI irq */
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if (d->irq < 32)
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return -EINVAL;
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mask = 1 << d->irq % 32;
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gpc_wake_irqs[idx] = on ? gpc_wake_irqs[idx] | mask :
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gpc_wake_irqs[idx] & ~mask;
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return 0;
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}
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void imx_gpc_mask_all(void)
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{
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void __iomem *reg_imr1 = gpc_base + GPC_IMR1;
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int i;
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for (i = 0; i < IMR_NUM; i++) {
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gpc_saved_imrs[i] = readl_relaxed(reg_imr1 + i * 4);
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writel_relaxed(~0, reg_imr1 + i * 4);
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}
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}
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void imx_gpc_restore_all(void)
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{
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void __iomem *reg_imr1 = gpc_base + GPC_IMR1;
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int i;
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for (i = 0; i < IMR_NUM; i++)
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writel_relaxed(gpc_saved_imrs[i], reg_imr1 + i * 4);
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}
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void imx_gpc_irq_unmask(struct irq_data *d)
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{
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void __iomem *reg;
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u32 val;
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/* Sanity check for SPI irq */
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if (d->irq < 32)
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return;
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reg = gpc_base + GPC_IMR1 + (d->irq / 32 - 1) * 4;
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val = readl_relaxed(reg);
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val &= ~(1 << d->irq % 32);
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writel_relaxed(val, reg);
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}
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void imx_gpc_irq_mask(struct irq_data *d)
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{
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void __iomem *reg;
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u32 val;
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/* Sanity check for SPI irq */
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if (d->irq < 32)
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return;
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reg = gpc_base + GPC_IMR1 + (d->irq / 32 - 1) * 4;
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val = readl_relaxed(reg);
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val |= 1 << (d->irq % 32);
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writel_relaxed(val, reg);
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}
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void __init imx_gpc_init(void)
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{
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struct device_node *np;
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int i;
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np = of_find_compatible_node(NULL, NULL, "fsl,imx6q-gpc");
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gpc_base = of_iomap(np, 0);
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WARN_ON(!gpc_base);
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/* Initially mask all interrupts */
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for (i = 0; i < IMR_NUM; i++)
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writel_relaxed(~0, gpc_base + GPC_IMR1 + i * 4);
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/* Register GPC as the secondary interrupt controller behind GIC */
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gic_arch_extn.irq_mask = imx_gpc_irq_mask;
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gic_arch_extn.irq_unmask = imx_gpc_irq_unmask;
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gic_arch_extn.irq_set_wake = imx_gpc_irq_set_wake;
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}
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