[PATCH v2 1/2] ARM: IMX5: cpuidle driver
Sascha Hauer
s.hauer at pengutronix.de
Wed Feb 16 03:11:03 EST 2011
On Fri, Feb 11, 2011 at 10:36:12AM +0100, yong.shen at linaro.org wrote:
> From: Yong Shen <yong.shen at freescale.com>
>
> implement cpuidle driver for iMX5 SOCs, leave cpuidle params to board
> related code.
>
> Signed-off-by: Yong Shen <yong.shen at freescale.com>
> ---
> arch/arm/mach-mx5/Makefile | 1 +
> arch/arm/mach-mx5/cpuidle.c | 113 +++++++++++++++++++++++++++++++++++++++++++
> arch/arm/mach-mx5/cpuidle.h | 26 ++++++++++
> 3 files changed, 140 insertions(+), 0 deletions(-)
> create mode 100644 arch/arm/mach-mx5/cpuidle.c
> create mode 100644 arch/arm/mach-mx5/cpuidle.h
>
> diff --git a/arch/arm/mach-mx5/Makefile b/arch/arm/mach-mx5/Makefile
> index 0d43be9..12239e0 100644
> --- a/arch/arm/mach-mx5/Makefile
> +++ b/arch/arm/mach-mx5/Makefile
> @@ -7,6 +7,7 @@ obj-y := cpu.o mm.o clock-mx51-mx53.o devices.o
> obj-$(CONFIG_SOC_IMX50) += mm-mx50.o
>
> obj-$(CONFIG_CPU_FREQ_IMX) += cpu_op-mx51.o
> +obj-$(CONFIG_CPU_IDLE) += cpuidle.o
> obj-$(CONFIG_MACH_MX51_BABBAGE) += board-mx51_babbage.o
> obj-$(CONFIG_MACH_MX51_3DS) += board-mx51_3ds.o
> obj-$(CONFIG_MACH_MX53_EVK) += board-mx53_evk.o
> diff --git a/arch/arm/mach-mx5/cpuidle.c b/arch/arm/mach-mx5/cpuidle.c
> new file mode 100644
> index 0000000..9d77c47
> --- /dev/null
> +++ b/arch/arm/mach-mx5/cpuidle.c
> @@ -0,0 +1,113 @@
> +/*
> + * arch/arm/mach-mx5/cpuidle.c
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#include <linux/io.h>
> +#include <linux/cpuidle.h>
> +#include <asm/proc-fns.h>
> +#include <mach/hardware.h>
> +#include "cpuidle.h"
> +#include "crm_regs.h"
> +
> +static struct imx_cpuidle_params *imx_cpuidle_params;
> +void imx_cpuidle_board_params(struct imx_cpuidle_params *cpuidle_params)
> +{
> + imx_cpuidle_params = cpuidle_params;
> +}
> +
> +extern int tzic_enable_wake(int is_idle);
> +static int imx_enter_idle(struct cpuidle_device *dev,
> + struct cpuidle_state *state)
> +{
> + struct timeval before, after;
> + int idle_time;
> + u32 plat_lpc, arm_srpgcr, ccm_clpcr;
> + u32 empgc0, empgc1;
> +
> + local_irq_disable();
> + do_gettimeofday(&before);
> +
> + plat_lpc = __raw_readl(MXC_CORTEXA8_PLAT_LPC) &
> + ~(MXC_CORTEXA8_PLAT_LPC_DSM);
One thing that strikes me here is the fact that this code can probably
run on i.MX53 aswell, right? It's only that these registers have
different addresses on i.MX53. The MXC_ prefix is therefore not a good
idea. Switching this to MX51_ and having an additional MX53_ register
leads to code duplication. This shows that it's a bad idea to code
fixed addresses in the code. We should go for base + offset instead
so that this code will have a better start on i.MX53. This of course
needs changes in the current crm_regs.h and probably in the i.MX51/53
clock code.
> + ccm_clpcr = __raw_readl(MXC_CCM_CLPCR) & ~(MXC_CCM_CLPCR_LPM_MASK);
> + arm_srpgcr = __raw_readl(MXC_SRPG_ARM_SRPGCR) & ~(MXC_SRPGCR_PCR);
> + empgc0 = __raw_readl(MXC_SRPG_EMPGC0_SRPGCR) & ~(MXC_SRPGCR_PCR);
> + empgc1 = __raw_readl(MXC_SRPG_EMPGC1_SRPGCR) & ~(MXC_SRPGCR_PCR);
> +
> + if (state == &dev->states[WAIT_CLK_ON])
> + ;
> + else if (state == &dev->states[WAIT_CLK_OFF])
> + ccm_clpcr |= (0x1 << MXC_CCM_CLPCR_LPM_OFFSET);
> + else if (state == &dev->states[WAIT_CLK_OFF_POWER_OFF]) {
> + /* Wait unclocked, power off */
> + plat_lpc |= MXC_CORTEXA8_PLAT_LPC_DSM
> + | MXC_CORTEXA8_PLAT_LPC_DBG_DSM;
> + arm_srpgcr |= MXC_SRPGCR_PCR;
> + ccm_clpcr |= (0x1 << MXC_CCM_CLPCR_LPM_OFFSET);
> + ccm_clpcr &= ~MXC_CCM_CLPCR_VSTBY;
> + ccm_clpcr &= ~MXC_CCM_CLPCR_SBYOS;
> + if (tzic_enable_wake(1) != 0) {
> + local_irq_enable();
> + return 0;
> + }
> + }
> +
> + __raw_writel(plat_lpc, MXC_CORTEXA8_PLAT_LPC);
> + __raw_writel(ccm_clpcr, MXC_CCM_CLPCR);
> + __raw_writel(arm_srpgcr, MXC_SRPG_ARM_SRPGCR);
> +
> + cpu_do_idle();
> +
> + do_gettimeofday(&after);
> + local_irq_enable();
> + idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC +
> + (after.tv_usec - before.tv_usec);
> + return idle_time;
> +}
> +
> +static struct cpuidle_driver imx_cpuidle_driver = {
> + .name = "imx_idle",
> + .owner = THIS_MODULE,
> +};
> +
> +static DEFINE_PER_CPU(struct cpuidle_device, imx_cpuidle_device);
> +
> +static int __init imx_cpuidle_init(void)
> +{
> + struct cpuidle_device *device;
> + int i;
> +
> + if (imx_cpuidle_params == NULL)
> + return -ENODEV;
> +
> + cpuidle_register_driver(&imx_cpuidle_driver);
> +
> + device = &per_cpu(imx_cpuidle_device, smp_processor_id());
> + device->state_count = IMX_MAX_CPUIDLE_STATE;
> +
> + for (i = 0; i < IMX_MAX_CPUIDLE_STATE && i < CPUIDLE_STATE_MAX; i++) {
> + device->states[i].enter = imx_enter_idle;
> + device->states[i].exit_latency = imx_cpuidle_params[i].latency;
> + device->states[i].flags = CPUIDLE_FLAG_TIME_VALID;
> + }
> +
> + strcpy(device->states[WAIT_CLK_ON].name, "WFI 0");
> + strcpy(device->states[WAIT_CLK_ON].desc, "Wait with clock on");
> + strcpy(device->states[WAIT_CLK_OFF].name, "WFI 1");
> + strcpy(device->states[WAIT_CLK_OFF].desc, "Wait with clock off");
> + strcpy(device->states[WAIT_CLK_OFF_POWER_OFF].name, "WFI 2");
> + strcpy(device->states[WAIT_CLK_OFF_POWER_OFF].desc,
> + "Wait with clock off and power gating");
> +
> + if (cpuidle_register_device(device)) {
> + printk(KERN_ERR "imx_cpuidle_init: Failed registering\n");
> + return -ENODEV;
> + }
> + return 0;
> +}
> +
> +late_initcall(imx_cpuidle_init);
> diff --git a/arch/arm/mach-mx5/cpuidle.h b/arch/arm/mach-mx5/cpuidle.h
> new file mode 100644
> index 0000000..e5ba495
> --- /dev/null
> +++ b/arch/arm/mach-mx5/cpuidle.h
> @@ -0,0 +1,26 @@
> +/*
> + * arch/arm/mach-mx5/cpuidle.h
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +enum {
> + WAIT_CLK_ON, /* c1 */
> + WAIT_CLK_OFF, /* c2 */
> + WAIT_CLK_OFF_POWER_OFF, /* c3 */
> + IMX_MAX_CPUIDLE_STATE,
> +};
> +
> +struct imx_cpuidle_params {
> + unsigned int latency;
> +};
> +
> +#ifdef CONFIG_CPU_IDLE
> +extern void imx_cpuidle_board_params(struct imx_cpuidle_params *cpuidle_params);
> +#else
> +inline void imx_cpuidle_board_params(struct imx_cpuidle_params *cpuidle_params)
> +{}
> +#endif
> +
> --
> 1.7.1
>
>
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