From: Sagar Dharia sdharia@codeaurora.org
Slimbus HW mandates that clock-pause sequence has to be executed before disabling relevant interface and core clocks. Runtime-PM's autosuspend feature is used here to enter/exit low power mode for Qualcomm's Slimbus controller. Autosuspend feature enables driver to avoid changing power-modes too frequently since entering clock-pause is an expensive sequence
Signed-off-by: Sagar Dharia sdharia@codeaurora.org Signed-off-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org --- drivers/slimbus/slim-qcom-ctrl.c | 128 +++++++++++++++++++++++++++++++++++++-- drivers/slimbus/slim-qcom.h | 1 + 2 files changed, 125 insertions(+), 4 deletions(-)
diff --git a/drivers/slimbus/slim-qcom-ctrl.c b/drivers/slimbus/slim-qcom-ctrl.c index d0574e1..05ba44f 100644 --- a/drivers/slimbus/slim-qcom-ctrl.c +++ b/drivers/slimbus/slim-qcom-ctrl.c @@ -21,6 +21,7 @@ #include <linux/of.h> #include <linux/dma-mapping.h> #include <linux/slimbus.h> +#include <linux/pm_runtime.h> #include "slim-qcom.h"
#define MSM_SLIM_NAME "msm_slim_ctrl" @@ -217,6 +218,30 @@ static irqreturn_t msm_slim_interrupt(int irq, void *d) return ret; }
+static int msm_clk_pause_wakeup(struct slim_controller *ctrl) +{ + struct msm_slim_ctrl *dev = slim_get_ctrldata(ctrl); + + clk_prepare_enable(dev->hclk); + clk_prepare_enable(dev->rclk); + enable_irq(dev->irq); + + writel_relaxed(1, dev->base + FRM_WAKEUP); + /* Make sure framer wakeup write goes through before ISR fires */ + mb(); + /** + * HW Workaround: Currently, slave is reporting lost-sync messages + * after slimbus comes out of clock pause. + * Transaction with slave fail before slave reports that message + * Give some time for that report to come + * Slimbus wakes up in clock gear 10 at 24.576MHz. With each superframe + * being 250 usecs, we wait for 5-10 superframes here to ensure + * we get the message + */ + usleep_range(1250, 2500); + return 0; +} + static int msm_xfer_msg(struct slim_controller *ctrl, struct slim_msg_txn *txn, void *pbuf) { @@ -286,7 +311,6 @@ static int msm_set_laddr(struct slim_controller *ctrl, */ msg.wbuf = buf; msg.num_bytes = 7; - ret = slim_processtxn(&dev->ctrl, &txn);
if (ret) @@ -417,6 +441,8 @@ static int msm_slim_probe(struct platform_device *pdev)
dev->ctrl.set_laddr = msm_set_laddr; dev->ctrl.xfer_msg = msm_xfer_msg; + dev->ctrl.wakeup = msm_clk_pause_wakeup; + dev->ctrl.tx.n = MSM_TX_MSGS; dev->ctrl.rx.n = MSM_RX_MSGS; dev->ctrl.tx.sl_sz = SLIM_MSGQ_BUF_LEN; @@ -532,6 +558,12 @@ static int msm_slim_probe(struct platform_device *pdev) */ mb();
+ pm_runtime_use_autosuspend(&pdev->dev); + pm_runtime_set_autosuspend_delay(&pdev->dev, MSM_SLIM_AUTOSUSPEND); + pm_runtime_set_active(&pdev->dev); + pm_runtime_mark_last_busy(&pdev->dev); + pm_runtime_enable(&pdev->dev); + dev_dbg(dev->dev, "MSM SB controller is up:ver:0x%x!\n", dev->ver); return 0;
@@ -562,14 +594,101 @@ static int msm_slim_remove(struct platform_device *pdev) dma_free_coherent(&pdev->dev, (ctrl->tx.sl_sz * ctrl->tx.n), ctrl->tx.base, ctrl->tx.phy);
- disable_irq(dev->irq); - clk_disable_unprepare(dev->rclk); - clk_disable_unprepare(dev->hclk); + pm_runtime_disable(&pdev->dev); slim_del_controller(&dev->ctrl); destroy_workqueue(dev->rxwq); return 0; }
+/** + * If PM_RUNTIME is not defined, these 2 functions become helper + * functions to be called from system suspend/resume. + */ +#ifdef CONFIG_PM +static int msm_slim_runtime_suspend(struct device *device) +{ + struct platform_device *pdev = to_platform_device(device); + struct msm_slim_ctrl *dev = platform_get_drvdata(pdev); + int ret; + + dev_dbg(device, "pm_runtime: suspending...\n"); + ret = slim_ctrl_clk_pause(&dev->ctrl, false, SLIM_CLK_UNSPECIFIED); + if (ret) { + dev_err(device, "clk pause not entered:%d", ret); + } else { + disable_irq(dev->irq); + clk_disable_unprepare(dev->hclk); + clk_disable_unprepare(dev->rclk); + } + return ret; +} + +static int msm_slim_runtime_resume(struct device *device) +{ + struct platform_device *pdev = to_platform_device(device); + struct msm_slim_ctrl *dev = platform_get_drvdata(pdev); + int ret = 0; + + dev_dbg(device, "pm_runtime: resuming...\n"); + ret = slim_ctrl_clk_pause(&dev->ctrl, true, 0); + if (ret) + dev_err(device, "clk pause not exited:%d", ret); + return ret; +} +#endif + +#ifdef CONFIG_PM_SLEEP +static int msm_slim_suspend(struct device *dev) +{ + int ret = 0; + + if (!pm_runtime_enabled(dev) || + (!pm_runtime_suspended(dev))) { + dev_dbg(dev, "system suspend"); + ret = msm_slim_runtime_suspend(dev); + } + if (ret == -EISCONN) { + /** + * If the clock pause failed due to active channels, there is + * a possibility that some audio stream is active during suspend. + * (e.g. modem usecase during suspend) + * We dont want to return suspend failure in that case so that + * display and relevant components can still go to suspend. + * If there is some other error, then it should prevent + * system level suspend + */ + ret = 0; + } + return ret; +} + +static int msm_slim_resume(struct device *dev) +{ + if (!pm_runtime_enabled(dev) || !pm_runtime_suspended(dev)) { + int ret; + + dev_dbg(dev, "system resume"); + ret = msm_slim_runtime_resume(dev); + if (!ret) { + pm_runtime_mark_last_busy(dev); + pm_request_autosuspend(dev); + } + return ret; + + } + return 0; +} +#endif /* CONFIG_PM_SLEEP */ + +static const struct dev_pm_ops msm_slim_dev_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(msm_slim_suspend, msm_slim_resume) + SET_RUNTIME_PM_OPS( + msm_slim_runtime_suspend, + msm_slim_runtime_resume, + NULL + ) +}; + static const struct of_device_id msm_slim_dt_match[] = { { .compatible = "qcom,slim", @@ -584,6 +703,7 @@ static struct platform_driver msm_slim_driver = { .name = MSM_SLIM_NAME, .owner = THIS_MODULE, .of_match_table = msm_slim_dt_match, + .pm = &msm_slim_dev_pm_ops, }, }; module_platform_driver(msm_slim_driver); diff --git a/drivers/slimbus/slim-qcom.h b/drivers/slimbus/slim-qcom.h index 0ad59c3..8b1d649 100644 --- a/drivers/slimbus/slim-qcom.h +++ b/drivers/slimbus/slim-qcom.h @@ -23,6 +23,7 @@ ((l) | ((mt) << 5) | ((mc) << 8) | ((dt) << 15) | ((ad) << 16))
#define SLIM_ROOT_FREQ 24576000 +#define MSM_SLIM_AUTOSUSPEND 1000
/* MAX message size over control channel */ #define SLIM_MSGQ_BUF_LEN 40