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From:   Samuel Holland <samuel@sholland.org>
To:     Maxime Ripard <mripard@kernel.org>,
        Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
        Chen-Yu Tsai <wens@csie.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org, linux-sunxi@googlegroups.com,
        Samuel Holland <samuel@sholland.org>
Subject: [PATCH] media: cedrus: Implement runtime PM
Date:   Tue,  7 Apr 2020 20:02:32 -0500
Message-Id: <20200408010232.48432-1-samuel@sholland.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

This allows the VE clocks and PLL_VE to be disabled most of the time.

Since the device is stateless, each frame gets a separate runtime PM
reference. Enable autosuspend so the PM callbacks are not run before and
after every frame.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---

I tested this with v4l2-request-test. I don't have the setup to do
anything more complicated at the moment.

---
 drivers/staging/media/sunxi/cedrus/cedrus.c   |   7 ++
 .../staging/media/sunxi/cedrus/cedrus_hw.c    | 115 ++++++++++++------
 .../staging/media/sunxi/cedrus/cedrus_hw.h    |   3 +
 3 files changed, 88 insertions(+), 37 deletions(-)

diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.c b/drivers/staging/media/sunxi/cedrus/cedrus.c
index 3fad5edccd17..9aa1fc8a6c26 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus.c
@@ -16,6 +16,7 @@
 #include <linux/platform_device.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/pm.h>
 
 #include <media/v4l2-device.h>
 #include <media/v4l2-ioctl.h>
@@ -474,6 +475,11 @@ static int cedrus_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static const struct dev_pm_ops cedrus_dev_pm_ops = {
+	SET_RUNTIME_PM_OPS(cedrus_hw_suspend,
+			   cedrus_hw_resume, NULL)
+};
+
 static const struct cedrus_variant sun4i_a10_cedrus_variant = {
 	.mod_rate	= 320000000,
 };
@@ -559,6 +565,7 @@ static struct platform_driver cedrus_driver = {
 	.driver		= {
 		.name		= CEDRUS_NAME,
 		.of_match_table	= of_match_ptr(cedrus_dt_match),
+		.pm		= &cedrus_dev_pm_ops,
 	},
 };
 module_platform_driver(cedrus_driver);
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
index daf5f244f93b..b84814d5afe4 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
@@ -19,6 +19,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/interrupt.h>
 #include <linux/clk.h>
+#include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>
 #include <linux/soc/sunxi/sunxi_sram.h>
@@ -63,6 +64,8 @@ int cedrus_engine_enable(struct cedrus_ctx *ctx, enum cedrus_codec codec)
 	if (ctx->src_fmt.width > 2048)
 		reg |= VE_MODE_PIC_WIDTH_MORE_2048;
 
+	pm_runtime_get_sync(ctx->dev->dev);
+
 	cedrus_write(ctx->dev, VE_MODE, reg);
 
 	return 0;
@@ -71,6 +74,9 @@ int cedrus_engine_enable(struct cedrus_ctx *ctx, enum cedrus_codec codec)
 void cedrus_engine_disable(struct cedrus_dev *dev)
 {
 	cedrus_write(dev, VE_MODE, VE_MODE_DISABLED);
+
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
 }
 
 void cedrus_dst_format_set(struct cedrus_dev *dev,
@@ -134,12 +140,72 @@ static irqreturn_t cedrus_irq(int irq, void *data)
 	else
 		state = VB2_BUF_STATE_DONE;
 
+	cedrus_engine_disable(dev);
+
 	v4l2_m2m_buf_done_and_job_finish(ctx->dev->m2m_dev, ctx->fh.m2m_ctx,
 					 state);
 
 	return IRQ_HANDLED;
 }
 
+int cedrus_hw_resume(struct device *d)
+{
+	struct cedrus_dev *dev = dev_get_drvdata(d);
+	int ret;
+
+	ret = clk_prepare_enable(dev->ahb_clk);
+	if (ret) {
+		dev_err(dev->dev, "Failed to enable AHB clock\n");
+
+		return ret;
+	}
+
+	ret = clk_prepare_enable(dev->mod_clk);
+	if (ret) {
+		dev_err(dev->dev, "Failed to enable MOD clock\n");
+
+		goto err_ahb_clk;
+	}
+
+	ret = clk_prepare_enable(dev->ram_clk);
+	if (ret) {
+		dev_err(dev->dev, "Failed to enable RAM clock\n");
+
+		goto err_mod_clk;
+	}
+
+	ret = reset_control_reset(dev->rstc);
+	if (ret) {
+		dev_err(dev->dev, "Failed to apply reset\n");
+
+		goto err_ram_clk;
+	}
+
+	return 0;
+
+err_ram_clk:
+	clk_disable_unprepare(dev->ram_clk);
+err_mod_clk:
+	clk_disable_unprepare(dev->mod_clk);
+err_ahb_clk:
+	clk_disable_unprepare(dev->ahb_clk);
+
+	return ret;
+}
+
+int cedrus_hw_suspend(struct device *d)
+{
+	struct cedrus_dev *dev = dev_get_drvdata(d);
+
+	reset_control_assert(dev->rstc);
+
+	clk_disable_unprepare(dev->ram_clk);
+	clk_disable_unprepare(dev->mod_clk);
+	clk_disable_unprepare(dev->ahb_clk);
+
+	return 0;
+}
+
 int cedrus_hw_probe(struct cedrus_dev *dev)
 {
 	const struct cedrus_variant *variant;
@@ -236,42 +302,19 @@ int cedrus_hw_probe(struct cedrus_dev *dev)
 		goto err_sram;
 	}
 
-	ret = clk_prepare_enable(dev->ahb_clk);
-	if (ret) {
-		dev_err(dev->dev, "Failed to enable AHB clock\n");
-
-		goto err_sram;
-	}
-
-	ret = clk_prepare_enable(dev->mod_clk);
-	if (ret) {
-		dev_err(dev->dev, "Failed to enable MOD clock\n");
-
-		goto err_ahb_clk;
-	}
-
-	ret = clk_prepare_enable(dev->ram_clk);
-	if (ret) {
-		dev_err(dev->dev, "Failed to enable RAM clock\n");
-
-		goto err_mod_clk;
-	}
-
-	ret = reset_control_reset(dev->rstc);
-	if (ret) {
-		dev_err(dev->dev, "Failed to apply reset\n");
-
-		goto err_ram_clk;
+	pm_runtime_set_autosuspend_delay(dev->dev, 1000);
+	pm_runtime_use_autosuspend(dev->dev);
+	pm_runtime_enable(dev->dev);
+	if (!pm_runtime_enabled(dev->dev)) {
+		ret = cedrus_hw_resume(dev->dev);
+		if (ret)
+			goto err_pm;
 	}
 
 	return 0;
 
-err_ram_clk:
-	clk_disable_unprepare(dev->ram_clk);
-err_mod_clk:
-	clk_disable_unprepare(dev->mod_clk);
-err_ahb_clk:
-	clk_disable_unprepare(dev->ahb_clk);
+err_pm:
+	pm_runtime_disable(dev->dev);
 err_sram:
 	sunxi_sram_release(dev->dev);
 err_mem:
@@ -282,11 +325,9 @@ int cedrus_hw_probe(struct cedrus_dev *dev)
 
 void cedrus_hw_remove(struct cedrus_dev *dev)
 {
-	reset_control_assert(dev->rstc);
-
-	clk_disable_unprepare(dev->ram_clk);
-	clk_disable_unprepare(dev->mod_clk);
-	clk_disable_unprepare(dev->ahb_clk);
+	pm_runtime_disable(dev->dev);
+	if (!pm_runtime_status_suspended(dev->dev))
+		cedrus_hw_suspend(dev->dev);
 
 	sunxi_sram_release(dev->dev);
 
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_hw.h b/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
index 604ff932fbf5..17822b470a1e 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
@@ -22,6 +22,9 @@ void cedrus_engine_disable(struct cedrus_dev *dev);
 void cedrus_dst_format_set(struct cedrus_dev *dev,
 			   struct v4l2_pix_format *fmt);
 
+int cedrus_hw_resume(struct device *dev);
+int cedrus_hw_suspend(struct device *dev);
+
 int cedrus_hw_probe(struct cedrus_dev *dev);
 void cedrus_hw_remove(struct cedrus_dev *dev);
 
-- 
2.24.1