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 <[email protected]> --- drivers/slimbus/slim-qcom-ctrl.c | 133 ++++++++++++++++++++++++++++++++++++++- drivers/slimbus/slim-qcom.h | 1 + 2 files changed, 132 insertions(+), 2 deletions(-) diff --git a/drivers/slimbus/slim-qcom-ctrl.c b/drivers/slimbus/slim-qcom-ctrl.c index feae9d1..ec8687d 100644 --- a/drivers/slimbus/slim-qcom-ctrl.c +++ b/drivers/slimbus/slim-qcom-ctrl.c @@ -21,6 +21,7 @@ #include <linux/clk.h> #include <linux/of.h> #include <linux/slimbus.h> +#include <linux/pm_runtime.h> #include "slim-qcom.h" #define MSM_SLIM_NAME "msm_slim_ctrl" @@ -193,6 +194,7 @@ rx_ret_irq: if (notify_rx) complete(&dev->rx_msgq_notify); } + pm_runtime_mark_last_busy(dev->dev); return IRQ_HANDLED; } @@ -211,6 +213,28 @@ static void msm_slim_wait_retry(struct msm_slim_ctrl *dev) msleep(msec_per_frm); } +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); + 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 void msm_slim_cb(void *ctx, int err) { if (err) @@ -225,14 +249,29 @@ static int msm_xfer_msg(struct slim_controller *ctrl, struct slim_msg_txn *txn) struct msm_slim_ctrl *dev = slim_get_ctrldata(ctrl); u32 *pbuf; u8 *puc; - int timeout; + int ret, timeout; u8 la = txn->la; + enum slim_clk_state cur_clk_state = ctrl->sched.clk_state; struct msm_wr_cb wr_cb = {msm_slim_cb, (void *)&done}; /* No support to send this dest-type of message */ if (txn->dt == SLIM_MSG_DEST_ENUMADDR) return -EPROTONOSUPPORT; + if (cur_clk_state == SLIM_CLK_ENTERING_PAUSE) { + if (txn->mc != SLIM_MSG_MC_BEGIN_RECONFIGURATION && + txn->mc != SLIM_MSG_MC_RECONFIGURE_NOW && + txn->mc != SLIM_MSG_MC_NEXT_PAUSE_CLOCK) + return -EBUSY; + } else { + ret = pm_runtime_get_sync(dev->dev); + if (ret < 0) { + pm_runtime_set_suspended(dev->dev); + dev_err(dev->dev, "runtime-pm vote failed:%d\n", ret); + return ret; + } + } + /* HW expects length field to be excluded */ txn->rl--; @@ -276,6 +315,8 @@ static int msm_xfer_msg(struct slim_controller *ctrl, struct slim_msg_txn *txn) txn->mt); mutex_unlock(&dev->txn_lock); + if (cur_clk_state != SLIM_CLK_ENTERING_PAUSE) + pm_runtime_put(dev->dev); return timeout ? 0 : -ETIMEDOUT; } @@ -295,6 +336,13 @@ static int msm_set_laddr(struct slim_controller *ctrl, ea[2] = (u8) (ead->prod_code & 0xFF); ea[1] = ead->dev_index; ea[0] = ead->instance; + + ret = pm_runtime_get_sync(dev->dev); + if (ret < 0) { + pm_runtime_set_suspended(dev->dev); + dev_err(dev->dev, "runtime-pm vote failed:%d\n", ret); + return ret; + } mutex_lock(&dev->txn_lock); /** * Retries are needed since bus may lose sync when multiple devices @@ -305,6 +353,7 @@ retry_laddr: buf = (u32 *)msm_slim_get_tx(dev, &wr_cb); if (buf == NULL) { mutex_unlock(&dev->txn_lock); + pm_runtime_put(dev->dev); return -ENOMEM; } @@ -332,6 +381,7 @@ retry_laddr: } } mutex_unlock(&dev->txn_lock); + pm_runtime_put(dev->dev); return ret; } @@ -512,6 +562,7 @@ 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; mutex_init(&dev->txn_lock); init_completion(&dev->rx_msgq_notify); @@ -615,6 +666,12 @@ static int msm_slim_probe(struct platform_device *pdev) /* Add devices registered with board-info now that controller is up */ slim_ctrl_add_boarddevs(&dev->ctrl); + 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; @@ -651,6 +708,7 @@ static int msm_slim_remove(struct platform_device *pdev) struct resource *slim_mem; struct resource *slew_mem = dev->slew_mem; + pm_runtime_disable(&pdev->dev); free_irq(dev->irq, dev); slim_del_controller(&dev->ctrl); clk_put(dev->rclk); @@ -671,20 +729,91 @@ static int msm_slim_remove(struct platform_device *pdev) 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 { + 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) { - return 0; + 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 + * 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[] = { diff --git a/drivers/slimbus/slim-qcom.h b/drivers/slimbus/slim-qcom.h index 32073fc..f37a10a 100644 --- a/drivers/slimbus/slim-qcom.h +++ b/drivers/slimbus/slim-qcom.h @@ -25,6 +25,7 @@ #define SLIM_ROOT_FREQ 24576000 #define INIT_MX_RETRIES 10 #define DEF_RETRY_MS 10 +#define MSM_SLIM_AUTOSUSPEND 1000 /* MAX message size over control channel */ #define SLIM_MSGQ_BUF_LEN 40 -- 1.8.2.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
