[PATCH v13 03/10] qcom: spm: Add Subsystem Power Manager driver
Lorenzo Pieralisi
lorenzo.pieralisi at arm.com
Thu Nov 27 07:01:37 PST 2014
On Thu, Nov 27, 2014 at 05:24:07AM +0000, Lina Iyer wrote:
[...]
> +static int spm_set_low_power_mode(enum pm_sleep_mode mode)
> +{
> + struct spm_driver_data *drv = per_cpu(cpu_spm_drv,
> + smp_processor_id());
> + u32 start_index;
> + u32 ctl_val;
> +
> + if (!drv)
> + return -ENXIO;
> +
> + start_index = drv->reg_data->start_index[mode];
> +
> + ctl_val = spm_register_read(drv, SPM_REG_SPM_CTL);
> + ctl_val &= ~(SPM_CTL_INDEX << SPM_CTL_INDEX_SHIFT);
> + ctl_val |= start_index << SPM_CTL_INDEX_SHIFT;
> + ctl_val |= SPM_CTL_EN;
> + spm_register_write(drv, SPM_REG_SPM_CTL, ctl_val);
> +
> + /* Ensure we have written the start address */
> + wmb();
Can you explain please what this wmb is meant to achieve ? If it is there
to make sure the write made it to the SPM that's not a proper way
to achieve it, the barrier ensures ordering, not write completion.
> +
> + return 0;
> +}
> +
> +static int qcom_pm_collapse(unsigned long int unused)
> +{
> + int ret;
> + u32 flag;
> + int cpu = smp_processor_id();
> +
> + ret = scm_set_warm_boot_addr(cpu_resume, cpu);
> + if (ret)
> + return ret;
> +
> + flag = SCM_L2_ON & SCM_FLUSH_FLAG_MASK;
> + scm_call_atomic1(SCM_SVC_BOOT, SCM_CMD_TERMINATE_PC, flag);
> +
> + /*
> + * Returns here only if there was a pending interrupt and we did not
> + * power down as a result.
> + */
> + return 0;
I know the return value is changed by the cpu_suspend implementation to
signal error when not returning from cpu_resume, but you should not
return 0 anyway.
> +}
> +
> +static int qcom_cpu_standby(void *unused)
> +{
> + int ret;
> +
> + ret = spm_set_low_power_mode(PM_SLEEP_MODE_STBY);
> + if (ret)
> + return ret;
> +
> + cpu_do_idle();
> +
> + return 0;
> +}
> +
> +static int qcom_cpu_spc(void *unused)
> +{ int ret;
> +
> + ret = spm_set_low_power_mode(PM_SLEEP_MODE_STBY);
> + if (ret)
> + return ret;
> +
> + cpu_pm_enter();
> + cpu_suspend(0, qcom_pm_collapse);
You must stash the return value and propagate it.
> + cpu_pm_exit();
> +
> + return 0;
> +}
> +
> +static struct spm_driver_data *spm_get_drv(struct platform_device *pdev,
> + int *spm_cpu)
> +{
> + struct spm_driver_data *drv = NULL;
> + struct device_node *cpu_node, *saw_node;
> + int cpu;
> + bool found = false;
> +
> + for_each_possible_cpu(cpu) {
> + cpu_node = of_cpu_device_node_get(cpu);
> + if (!cpu_node)
> + continue;
> + saw_node = of_parse_phandle(cpu_node, "qcom,saw", 0);
+ if (saw_node) {
+ if (saw_node == pdev->dev.of_node)
+ found = true;
+ of_node_put(saw_node);
+ }
can be:
found = (saw_node == pdev->dev.of_node);
of_node_put(saw_node);
Thanks,
Lorenzo
> + of_node_put(cpu_node);
> + if (found)
> + break;
> + }
> +
> + if (found) {
> + drv = devm_kzalloc(&pdev->dev, sizeof(*drv), GFP_KERNEL);
> + if (drv)
> + *spm_cpu = cpu;
> + }
> +
> + return drv;
> +}
> +
> +static const struct of_device_id spm_match_table[] = {
> + { .compatible = "qcom,msm8974-saw2-v2.1-cpu",
> + .data = &spm_reg_8974_8084_cpu },
> + { .compatible = "qcom,apq8084-saw2-v2.1-cpu",
> + .data = &spm_reg_8974_8084_cpu },
> + { .compatible = "qcom,apq8064-saw2-v1.1-cpu",
> + .data = &spm_reg_8064_cpu },
> + { },
> +};
> +
> +static const struct qcom_cpu_pm_ops lpm_ops = {
> + .standby = qcom_cpu_standby,
> + .spc = qcom_cpu_spc,
> +};
> +
> +static int spm_dev_probe(struct platform_device *pdev)
> +{
> + struct spm_driver_data *drv;
> + struct resource *res;
> + const struct of_device_id *match_id;
> + void __iomem *addr;
> + int cpu = -EINVAL;
> + static bool cpuidle_drv_init;
> + const struct platform_device_info qcom_cpuidle_info = {
> + .name = "qcom_cpuidle",
> + .id = -1,
> + .data = &lpm_ops,
> + .size_data = sizeof(lpm_ops),
> + };
> +
> + drv = spm_get_drv(pdev, &cpu);
> + if (!drv || cpu < 0)
> + return -EINVAL;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + drv->reg_base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(drv->reg_base))
> + return PTR_ERR(drv->reg_base);
> +
> + match_id = of_match_node(spm_match_table, pdev->dev.of_node);
> + if (!match_id)
> + return -ENODEV;
> +
> + drv->reg_data = match_id->data;
> +
> + /* Write the SPM sequences first.. */
> + addr = drv->reg_base + drv->reg_data->reg_offset[SPM_REG_SEQ_ENTRY];
> + __iowrite32_copy(addr, drv->reg_data->seq,
> + ARRAY_SIZE(drv->reg_data->seq) / 4);
> +
> + /*
> + * ..and then the control registers.
> + * On some SoC's if the control registers are written first and if the
> + * CPU was held in reset, the reset signal could trigger the SPM state
> + * machine, before the sequences are completely written.
> + */
> + spm_register_write(drv, SPM_REG_CFG, drv->reg_data->spm_cfg);
> + spm_register_write(drv, SPM_REG_DLY, drv->reg_data->spm_dly);
> + spm_register_write(drv, SPM_REG_PMIC_DLY, drv->reg_data->pmic_dly);
> +
> + spm_register_write(drv, SPM_REG_PMIC_DATA_0,
> + drv->reg_data->pmic_data[0]);
> + spm_register_write(drv, SPM_REG_PMIC_DATA_1,
> + drv->reg_data->pmic_data[1]);
> +
> + /*
> + * Ensure all observers see the above register writes before the
> + * cpuidle driver is allowed to use the SPM.
> + */
> + wmb();
> + per_cpu(cpu_spm_drv, cpu) = drv;
> +
> + if (!cpuidle_drv_init) {
> + platform_device_register_full(&qcom_cpuidle_info);
> + cpuidle_drv_init = true;
> + }
> +
> + return 0;
> +}
> +
> +static struct platform_driver spm_driver = {
> + .probe = spm_dev_probe,
> + .driver = {
> + .name = "saw",
> + .of_match_table = spm_match_table,
> + },
> +};
> +
> +module_platform_driver(spm_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("SAW power controller driver");
> +MODULE_ALIAS("platform:saw");
> diff --git a/include/soc/qcom/pm.h b/include/soc/qcom/pm.h
> new file mode 100644
> index 0000000..d9a56d7
> --- /dev/null
> +++ b/include/soc/qcom/pm.h
> @@ -0,0 +1,31 @@
> +/*
> + * Copyright (c) 2009-2014, The Linux Foundation. All rights reserved.
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation, and
> + * may be copied, distributed, and modified under those terms.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#ifndef __QCOM_PM_H
> +#define __QCOM_PM_H
> +
> +enum pm_sleep_mode {
> + PM_SLEEP_MODE_STBY,
> + PM_SLEEP_MODE_RET,
> + PM_SLEEP_MODE_SPC,
> + PM_SLEEP_MODE_PC,
> + PM_SLEEP_MODE_NR,
> +};
> +
> +struct qcom_cpu_pm_ops {
> + int (*standby)(void *data);
> + int (*spc)(void *data);
> +};
> +
> +#endif /* __QCOM_PM_H */
> --
> 2.1.0
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
More information about the linux-arm-kernel
mailing list