[PATCH v10 0/5] rk3399 support ddr frequency scaling

[PATCH v10 0/5] rk3399 support ddr frequency scaling

[Lin Huang]

rk3399 platform have dfi controller can monitor ddr load,
and dcf controller to handle ddr register so we can get the
right ddr frequency and make ddr controller happy work(which
will implement in bl31). So we do ddr frequency scaling with
following flow:

             kernel                                bl31

        monitor ddr load
                |
                |
        get_target_rate
                |
                |           pass rate to bl31
        clk_set_rate(ddr) --------------------->run dcf flow
                |                                   |
                |                                   |
        wait dcf interrupt<-------------------trigger dcf interrupt
                |
                |
              return


Lin Huang (5):
  Documentation: bindings: add dt documentation for dfi controller
  PM / devfreq: event: support rockchip dfi controller
  Documentation: bindings: add dt documentation for rk3399 dmc
  PM / devfreq: rockchip: add devfreq driver for rk3399 dmc
  drm/rockchip: Add dmc notifier in vop driver

Following patch:
clk: rockchip: add new clock-type for the ddrclk
clk: rockchip: rk3399: add SCLK_DDRCLK ID for ddrc
clk: rockchip: rk3399: add ddrc clock support
have applied to:
http://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip.git/v4.9-clk/next


 .../bindings/devfreq/event/rockchip-dfi.txt        |  19 +
 .../devicetree/bindings/devfreq/rk3399_dmc.txt     | 210 +++++++++
 drivers/devfreq/Kconfig                            |  11 +
 drivers/devfreq/Makefile                           |   1 +
 drivers/devfreq/event/Kconfig                      |   7 +
 drivers/devfreq/event/Makefile                     |   1 +
 drivers/devfreq/event/rockchip-dfi.c               | 256 +++++++++++
 drivers/devfreq/rk3399_dmc.c                       | 480 +++++++++++++++++++++
 drivers/gpu/drm/rockchip/rockchip_drm_vop.c        | 116 +++++
 9 files changed, 1101 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/devfreq/event/rockchip-dfi.txt
 create mode 100644 Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt
 create mode 100644 drivers/devfreq/event/rockchip-dfi.c
 create mode 100644 drivers/devfreq/rk3399_dmc.c

-- 
2.6.6

[PATCH v10 1/5] Documentation: bindings: add dt documentation for dfi controller

[Lin Huang]

This patch adds the documentation for rockchip dfi devfreq-event driver.

Signed-off-by: Lin Huang <hl@rock-chips.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
---
Changes in v10:
- None

Changes in v9:
- reorder compatible and reg

Changes in v8:
- delete a unuse blank line

Changes in v7:
- None

Changes in v6:
- None

Changes in v5:
- None

Changes in v4:
- None

Changes in v3:
- None

Changes in v2:
- None 

Changes in v1:
- None

 .../bindings/devfreq/event/rockchip-dfi.txt           | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/devfreq/event/rockchip-dfi.txt

diff --git a/Documentation/devicetree/bindings/devfreq/event/rockchip-dfi.txt b/Documentation/devicetree/bindings/devfreq/event/rockchip-dfi.txt
new file mode 100644
index 0000000..f223313
--- /dev/null
+++ b/Documentation/devicetree/bindings/devfreq/event/rockchip-dfi.txt
@@ -0,0 +1,19 @@
+
+* Rockchip rk3399 DFI device
+
+Required properties:
+- compatible: Must be "rockchip,rk3399-dfi".
+- reg: physical base address of each DFI and length of memory mapped region
+- rockchip,pmu: phandle to the syscon managing the "pmu general register files"
+- clocks: phandles for clock specified in "clock-names" property
+- clock-names : the name of clock used by the DFI, must be "pclk_ddr_mon";
+
+Example:
+	dfi: dfi@0xff630000 {
+		compatible = "rockchip,rk3399-dfi";
+		reg = <0x00 0xff630000 0x00 0x4000>;
+		rockchip,pmu = <&pmugrf>;
+		clocks = <&cru PCLK_DDR_MON>;
+		clock-names = "pclk_ddr_mon";
+		status = "disabled";
+	};
-- 
2.6.6

Re: [PATCH v10 1/5] Documentation: bindings: add dt documentation for dfi controller

[Rob Herring]

On Mon, Sep 05, 2016 at 01:06:07PM +0800, Lin Huang wrote:
> This patch adds the documentation for rockchip dfi devfreq-event driver.
> 
> Signed-off-by: Lin Huang <hl@rock-chips.com>
> Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
> Changes in v10:
> - None
> 
> Changes in v9:
> - reorder compatible and reg
> 
> Changes in v8:
> - delete a unuse blank line
> 
> Changes in v7:
> - None
> 
> Changes in v6:
> - None
> 
> Changes in v5:
> - None
> 
> Changes in v4:
> - None
> 
> Changes in v3:
> - None
> 
> Changes in v2:
> - None 
> 
> Changes in v1:
> - None
> 
>  .../bindings/devfreq/event/rockchip-dfi.txt           | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/devfreq/event/rockchip-dfi.txt
> 
> diff --git a/Documentation/devicetree/bindings/devfreq/event/rockchip-dfi.txt b/Documentation/devicetree/bindings/devfreq/event/rockchip-dfi.txt
> new file mode 100644
> index 0000000..f223313
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/devfreq/event/rockchip-dfi.txt
> @@ -0,0 +1,19 @@
> +
> +* Rockchip rk3399 DFI device
> +
> +Required properties:
> +- compatible: Must be "rockchip,rk3399-dfi".
> +- reg: physical base address of each DFI and length of memory mapped region
> +- rockchip,pmu: phandle to the syscon managing the "pmu general register files"
> +- clocks: phandles for clock specified in "clock-names" property
> +- clock-names : the name of clock used by the DFI, must be "pclk_ddr_mon";
> +
> +Example:
> +	dfi: dfi@0xff630000 {

Drop the '0x'. With that,

Acked-by: Rob Herring <robh@kernel.org>

> +		compatible = "rockchip,rk3399-dfi";
> +		reg = <0x00 0xff630000 0x00 0x4000>;
> +		rockchip,pmu = <&pmugrf>;
> +		clocks = <&cru PCLK_DDR_MON>;
> +		clock-names = "pclk_ddr_mon";
> +		status = "disabled";
> +	};
> -- 
> 2.6.6
> 
> --
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> the body of a message to majordomo@vger.kernel.org
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[PATCH v10 2/5] PM / devfreq: event: support rockchip dfi controller

[Lin Huang]

on rk3399 platform, there is dfi conroller can monitor
ddr load, base on this result, we can do ddr freqency
scaling.

Signed-off-by: Lin Huang <hl@rock-chips.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
---
Changes in v10:
-None

Changes in v9:
-None

Changes in v8:
-None

Changes in v7:
-access need to *4 to get right DDR loading

Changes in v6:
-None

Changes in v5:
-None

Changes in v4:
-None

Changes in v3:
-None

Changes in v2:
-None 

Changes in v1:
-None

 drivers/devfreq/event/Kconfig        |   7 +
 drivers/devfreq/event/Makefile       |   1 +
 drivers/devfreq/event/rockchip-dfi.c | 256 +++++++++++++++++++++++++++++++++++
 3 files changed, 264 insertions(+)
 create mode 100644 drivers/devfreq/event/rockchip-dfi.c

diff --git a/drivers/devfreq/event/Kconfig b/drivers/devfreq/event/Kconfig
index eb6f74a..20d82c2 100644
--- a/drivers/devfreq/event/Kconfig
+++ b/drivers/devfreq/event/Kconfig
@@ -30,4 +30,11 @@ config DEVFREQ_EVENT_EXYNOS_PPMU
 	  (Platform Performance Monitoring Unit) counters to estimate the
 	  utilization of each module.
 
+config DEVFREQ_EVENT_ROCKCHIP_DFI
+	tristate "ROCKCHIP DFI DEVFREQ event Driver"
+	depends on ARCH_ROCKCHIP
+	help
+	  This add the devfreq-event driver for Rockchip SoC. It provides DFI
+	  (DDR Monitor Module) driver to count ddr load.
+
 endif # PM_DEVFREQ_EVENT
diff --git a/drivers/devfreq/event/Makefile b/drivers/devfreq/event/Makefile
index 3d6afd3..dda7090 100644
--- a/drivers/devfreq/event/Makefile
+++ b/drivers/devfreq/event/Makefile
@@ -2,3 +2,4 @@
 
 obj-$(CONFIG_DEVFREQ_EVENT_EXYNOS_NOCP) += exynos-nocp.o
 obj-$(CONFIG_DEVFREQ_EVENT_EXYNOS_PPMU) += exynos-ppmu.o
+obj-$(CONFIG_DEVFREQ_EVENT_ROCKCHIP_DFI) += rockchip-dfi.o
diff --git a/drivers/devfreq/event/rockchip-dfi.c b/drivers/devfreq/event/rockchip-dfi.c
new file mode 100644
index 0000000..43fcc5a
--- /dev/null
+++ b/drivers/devfreq/event/rockchip-dfi.c
@@ -0,0 +1,256 @@
+/*
+ * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
+ * Author: Lin Huang <hl@rock-chips.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#include <linux/clk.h>
+#include <linux/devfreq-event.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/of.h>
+
+#define RK3399_DMC_NUM_CH	2
+
+/* DDRMON_CTRL */
+#define DDRMON_CTRL	0x04
+#define CLR_DDRMON_CTRL	(0x1f0000 << 0)
+#define LPDDR4_EN	(0x10001 << 4)
+#define HARDWARE_EN	(0x10001 << 3)
+#define LPDDR3_EN	(0x10001 << 2)
+#define SOFTWARE_EN	(0x10001 << 1)
+#define SOFTWARE_DIS	(0x10000 << 1)
+#define TIME_CNT_EN	(0x10001 << 0)
+
+#define DDRMON_CH0_COUNT_NUM		0x28
+#define DDRMON_CH0_DFI_ACCESS_NUM	0x2c
+#define DDRMON_CH1_COUNT_NUM		0x3c
+#define DDRMON_CH1_DFI_ACCESS_NUM	0x40
+
+/* pmu grf */
+#define PMUGRF_OS_REG2	0x308
+#define DDRTYPE_SHIFT	13
+#define DDRTYPE_MASK	7
+
+enum {
+	DDR3 = 3,
+	LPDDR3 = 6,
+	LPDDR4 = 7,
+	UNUSED = 0xFF
+};
+
+struct dmc_usage {
+	u32 access;
+	u32 total;
+};
+
+/*
+ * The dfi controller can monitor DDR load. It has an upper and lower threshold
+ * for the operating points. Whenever the usage leaves these bounds an event is
+ * generated to indicate the DDR frequency should be changed.
+ */
+struct rockchip_dfi {
+	struct devfreq_event_dev *edev;
+	struct devfreq_event_desc *desc;
+	struct dmc_usage ch_usage[RK3399_DMC_NUM_CH];
+	struct device *dev;
+	void __iomem *regs;
+	struct regmap *regmap_pmu;
+	struct clk *clk;
+};
+
+static void rockchip_dfi_start_hardware_counter(struct devfreq_event_dev *edev)
+{
+	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
+	void __iomem *dfi_regs = info->regs;
+	u32 val;
+	u32 ddr_type;
+
+	/* get ddr type */
+	regmap_read(info->regmap_pmu, PMUGRF_OS_REG2, &val);
+	ddr_type = (val >> DDRTYPE_SHIFT) & DDRTYPE_MASK;
+
+	/* clear DDRMON_CTRL setting */
+	writel_relaxed(CLR_DDRMON_CTRL, dfi_regs + DDRMON_CTRL);
+
+	/* set ddr type to dfi */
+	if (ddr_type == LPDDR3)
+		writel_relaxed(LPDDR3_EN, dfi_regs + DDRMON_CTRL);
+	else if (ddr_type == LPDDR4)
+		writel_relaxed(LPDDR4_EN, dfi_regs + DDRMON_CTRL);
+
+	/* enable count, use software mode */
+	writel_relaxed(SOFTWARE_EN, dfi_regs + DDRMON_CTRL);
+}
+
+static void rockchip_dfi_stop_hardware_counter(struct devfreq_event_dev *edev)
+{
+	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
+	void __iomem *dfi_regs = info->regs;
+
+	writel_relaxed(SOFTWARE_DIS, dfi_regs + DDRMON_CTRL);
+}
+
+static int rockchip_dfi_get_busier_ch(struct devfreq_event_dev *edev)
+{
+	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
+	u32 tmp, max = 0;
+	u32 i, busier_ch = 0;
+	void __iomem *dfi_regs = info->regs;
+
+	rockchip_dfi_stop_hardware_counter(edev);
+
+	/* Find out which channel is busier */
+	for (i = 0; i < RK3399_DMC_NUM_CH; i++) {
+		info->ch_usage[i].access = readl_relaxed(dfi_regs +
+				DDRMON_CH0_DFI_ACCESS_NUM + i * 20) * 4;
+		info->ch_usage[i].total = readl_relaxed(dfi_regs +
+				DDRMON_CH0_COUNT_NUM + i * 20);
+		tmp = info->ch_usage[i].access;
+		if (tmp > max) {
+			busier_ch = i;
+			max = tmp;
+		}
+	}
+	rockchip_dfi_start_hardware_counter(edev);
+
+	return busier_ch;
+}
+
+static int rockchip_dfi_disable(struct devfreq_event_dev *edev)
+{
+	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
+
+	rockchip_dfi_stop_hardware_counter(edev);
+	clk_disable_unprepare(info->clk);
+
+	return 0;
+}
+
+static int rockchip_dfi_enable(struct devfreq_event_dev *edev)
+{
+	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
+	int ret;
+
+	ret = clk_prepare_enable(info->clk);
+	if (ret) {
+		dev_err(&edev->dev, "failed to enable dfi clk: %d\n", ret);
+		return ret;
+	}
+
+	rockchip_dfi_start_hardware_counter(edev);
+	return 0;
+}
+
+static int rockchip_dfi_set_event(struct devfreq_event_dev *edev)
+{
+	return 0;
+}
+
+static int rockchip_dfi_get_event(struct devfreq_event_dev *edev,
+				  struct devfreq_event_data *edata)
+{
+	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
+	int busier_ch;
+
+	busier_ch = rockchip_dfi_get_busier_ch(edev);
+
+	edata->load_count = info->ch_usage[busier_ch].access;
+	edata->total_count = info->ch_usage[busier_ch].total;
+
+	return 0;
+}
+
+static const struct devfreq_event_ops rockchip_dfi_ops = {
+	.disable = rockchip_dfi_disable,
+	.enable = rockchip_dfi_enable,
+	.get_event = rockchip_dfi_get_event,
+	.set_event = rockchip_dfi_set_event,
+};
+
+static const struct of_device_id rockchip_dfi_id_match[] = {
+	{ .compatible = "rockchip,rk3399-dfi" },
+	{ },
+};
+
+static int rockchip_dfi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rockchip_dfi *data;
+	struct resource *res;
+	struct devfreq_event_desc *desc;
+	struct device_node *np = pdev->dev.of_node, *node;
+
+	data = devm_kzalloc(dev, sizeof(struct rockchip_dfi), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	data->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(data->regs))
+		return PTR_ERR(data->regs);
+
+	data->clk = devm_clk_get(dev, "pclk_ddr_mon");
+	if (IS_ERR(data->clk)) {
+		dev_err(dev, "Cannot get the clk dmc_clk\n");
+		return PTR_ERR(data->clk);
+	};
+
+	/* try to find the optional reference to the pmu syscon */
+	node = of_parse_phandle(np, "rockchip,pmu", 0);
+	if (node) {
+		data->regmap_pmu = syscon_node_to_regmap(node);
+		if (IS_ERR(data->regmap_pmu))
+			return PTR_ERR(data->regmap_pmu);
+	}
+	data->dev = dev;
+
+	desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL);
+	if (!desc)
+		return -ENOMEM;
+
+	desc->ops = &rockchip_dfi_ops;
+	desc->driver_data = data;
+	desc->name = np->name;
+	data->desc = desc;
+
+	data->edev = devm_devfreq_event_add_edev(&pdev->dev, desc);
+	if (IS_ERR(data->edev)) {
+		dev_err(&pdev->dev,
+			"failed to add devfreq-event device\n");
+		return PTR_ERR(data->edev);
+	}
+
+	platform_set_drvdata(pdev, data);
+
+	return 0;
+}
+
+static struct platform_driver rockchip_dfi_driver = {
+	.probe	= rockchip_dfi_probe,
+	.driver = {
+		.name	= "rockchip-dfi",
+		.of_match_table = rockchip_dfi_id_match,
+	},
+};
+module_platform_driver(rockchip_dfi_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Lin Huang <hl@rock-chips.com>");
+MODULE_DESCRIPTION("Rockchip DFI driver");
-- 
2.6.6

[PATCH v10 3/5] Documentation: bindings: add dt documentation for rk3399 dmc

[Lin Huang]

This patch adds the documentation for rockchip rk3399 dmc driver.

Signed-off-by: Lin Huang <hl@rock-chips.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
---
Changes in v10:
- add rockchip prefix in property describe

Changes in v9:
- add ddr timing property to node

Changes in v8:
- add ddr timing properties

Changes in v7:
- None

Changes in v6:
-Add more detail in Documentation

Changes in v5:
-None

Changes in v4:
-None

Changes in v3:
-None

Changes in v2:
-None 

Changes in v1:
-None
 .../devicetree/bindings/devfreq/rk3399_dmc.txt     | 202 +++++++++++++++++++++
 1 file changed, 202 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt

diff --git a/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt b/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt
new file mode 100644
index 0000000..84660a3
--- /dev/null
+++ b/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt
@@ -0,0 +1,210 @@
+* Rockchip rk3399 DMC(Dynamic Memory Controller) device
+
+Required properties:
+- compatible:		 Must be "rockchip,rk3399-dmc".
+- devfreq-events:	 Node to get DDR loading, Refer to
+			 Documentation/devicetree/bindings/devfreq/
+			 rockchip-dfi.txt
+- interrupts:		 The interrupt number to the CPU. The interrupt
+			 specifier format depends on the interrupt controller.
+			 It should be DCF interrupts, when DDR dvfs finish,
+			 it will happen.
+- clocks:		 Phandles for clock specified in "clock-names" property
+- clock-names :		 The name of clock used by the DFI, must be
+			 "pclk_ddr_mon";
+- operating-points-v2:	 Refer to Documentation/devicetree/bindings/power/opp.txt
+			 for details.
+- center-supply:	 DMC supply node.
+- status:		 Marks the node enabled/disabled.
+
+Following properties are ddr timing:
+
+- rockchip,dram_speed_bin :	  Value reference include/dt-bindings/clock/ddr.h,
+				  it select ddr3 cl-trp-trcd type, default value
+				  "DDR3_DEFAULT".it must selected according to
+				  "Speed Bin" in ddr3 datasheet, DO NOT use
+				  smaller "Speed Bin" than ddr3 exactly is.
+
+- rockchip,pd_idle :		  Config the PD_IDLE value, defined the power-down
+				  idle period, memories are places into power-down
+				  mode if bus is idle for PD_IDLE DFI clocks.
+
+- rockchip,sr_idle :		  Configure the SR_IDLE value, defined the
+				  selfrefresh idle period, memories are places
+				  into self-refresh mode if bus is idle for
+				  SR_IDLE*1024 DFI clocks (DFI clocks freq is
+				  half of dram's clocks), defaule value is "0".
+
+- rockchip,sr_mc_gate_idle :	  Defined the self-refresh with memory and
+				  controller clock gating idle period, memories
+				  are places into self-refresh mode and memory
+				  controller clock arg gating if bus is idle for
+				  sr_mc_gate_idle*1024 DFI clocks.
+
+- rockchip,srpd_lite_idle :	  Defined the self-refresh power down idle
+				  period, memories are places into self-refresh
+				  power down mode if bus is idle for
+				  srpd_lite_idle*1024 DFI clocks. This parameter
+				  is for LPDDR4 only.
+
+- rockchip,standby_idle :	  Defined the standby idle period, memories are
+				  places into self-refresh than controller, pi,
+				  phy and dram clock will gating if bus is idle
+				  for standby_idle * DFI clocks.
+
+- rockchip,dram_dll_disb_freq :  It's defined the DDR3 dll bypass frequency in
+				  MHz, when ddr freq less than DRAM_DLL_DISB_FREQ,
+				  ddr3 dll will bypssed note: if dll was bypassed,
+				  the odt also stop working.
+
+- rockchip,phy_dll_disb_freq :	  Defined the PHY dll bypass frequency in
+				  MHz (Mega Hz), when ddr freq less than
+				  DRAM_DLL_DISB_FREQ, phy dll will bypssed.
+				  note: phy dll and phy odt are independent.
+
+- rockchip,ddr3_odt_disb_freq :  When dram type is DDR3, this parameter defined
+				  the odt disable frequency in MHz (Mega Hz),
+				  when ddr frequency less then ddr3_odt_disb_freq,
+				  the odt on dram side and controller side are
+				  both disabled.
+
+- rockchip,ddr3_drv :		  When dram type is DDR3, this parameter define
+				  the dram side driver stength in ohm, default
+				  value is DDR3_DS_40ohm.
+
+- rockchip,ddr3_odt :		  When dram type is DDR3, this parameter define
+				  the dram side ODT stength in ohm, default value
+				  is DDR3_ODT_120ohm.
+
+- rockchip,phy_ddr3_ca_drv :	  When dram type is DDR3, this parameter define
+				  the phy side CA line(incluing command line,
+				  address line and clock line) driver strength.
+				  Default value is PHY_DRV_ODT_40.
+
+- rockchip,phy_ddr3_dq_drv :	  When dram type is DDR3, this parameter define
+				  the phy side DQ line(incluing DQS/DQ/DM line)
+				  driver strength. default value is PHY_DRV_ODT_40.
+
+- rockchip,phy_ddr3_odt : 	  When dram type is DDR3, this parameter define the
+				  phy side odt strength, default value is
+				  PHY_DRV_ODT_240.
+
+- rockchip,lpddr3_odt_disb_freq : When dram type is LPDDR3, this parameter defined
+				  then odt disable frequency in MHz (Mega Hz),
+				  when ddr frequency less then ddr3_odt_disb_freq,
+				  the odt on dram side and controller side are
+				  both disabled.
+
+- rockchip,lpddr3_drv :	  When dram type is LPDDR3, this parameter define
+				  the dram side driver stength in ohm, default
+				  value is LP3_DS_34ohm.
+
+- rockchip,lpddr3_odt :	  When dram type is LPDDR3, this parameter define
+				  the dram side ODT stength in ohm, default value
+				  is LP3_ODT_240ohm.
+
+- rockchip,phy_lpddr3_ca_drv :	  When dram type is LPDDR3, this parameter define
+				  the phy side CA line(incluing command line,
+				  address line and clock line) driver strength.
+				  default value is PHY_DRV_ODT_40.
+
+- rockchip,phy_lpddr3_dq_drv :	  When dram type is LPDDR3, this parameter define
+				  the phy side DQ line(incluing DQS/DQ/DM line)
+				  driver strength. default value is
+				  PHY_DRV_ODT_40.
+
+- rockchip,phy_lpddr3_odt : 	  When dram type is LPDDR3, this parameter define
+				  the phy side odt strength, default value is
+				  PHY_DRV_ODT_240.
+
+- rockchip,lpddr4_odt_disb_freq : When dram type is LPDDR4, this parameter
+				  defined the odt disable frequency in
+				  MHz (Mega Hz), when ddr frequency less then
+				  ddr3_odt_disb_freq, the odt on dram side and
+				  controller side are both disabled.
+
+- rockchip,lpddr4_drv :	  When dram type is LPDDR4, this parameter define
+				  the dram side driver stength in ohm, default
+				  value is LP4_PDDS_60ohm.
+
+- rockchip,lpddr4_dq_odt : 	  When dram type is LPDDR4, this parameter define
+				  the dram side ODT on dqs/dq line stength in ohm,
+				  default value is LP4_DQ_ODT_40ohm.
+
+- rockchip,lpddr4_ca_odt :	  When dram type is LPDDR4, this parameter define
+				  the dram side ODT on ca line stength in ohm,
+				  default value is LP4_CA_ODT_40ohm.
+
+- rockchip,phy_lpddr4_ca_drv :	  When dram type is LPDDR4, this parameter define
+				  the phy side  CA line(incluing command address
+				  line) driver strength. default value is
+				  PHY_DRV_ODT_40.
+
+- rockchip,phy_lpddr4_ck_cs_drv : When dram type is LPDDR4, this parameter define
+				  the phy side clock line and cs line driver
+				  strength. default value is PHY_DRV_ODT_80.
+
+- rockchip,phy_lpddr4_dq_drv :	  When dram type is LPDDR4, this parameter define
+				  the phy side DQ line(incluing DQS/DQ/DM line)
+				  driver strength. default value is PHY_DRV_ODT_80.
+
+- rockchip,phy_lpddr4_odt :	  When dram type is LPDDR4, this parameter define
+				  the phy side odt strength, default value is
+				  PHY_DRV_ODT_60.
+
+Example:
+	dmc_opp_table: dmc_opp_table {
+		compatible = "operating-points-v2";
+
+		opp00 {
+			opp-hz = /bits/ 64 <300000000>;
+			opp-microvolt = <900000>;
+		};
+		opp01 {
+			opp-hz = /bits/ 64 <666000000>;
+			opp-microvolt = <900000>;
+		};
+	};
+
+	dmc: dmc {
+		compatible = "rockchip,rk3399-dmc";
+		devfreq-events = <&dfi>;
+		interrupts = <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&cru SCLK_DDRCLK>;
+		clock-names = "dmc_clk";
+		operating-points-v2 = <&dmc_opp_table>;
+		center-supply = <&ppvar_centerlogic>;
+		upthreshold = <15>;
+		downdifferential = <10>;
+		rockchip,ddr3_speed_bin = <21>;
+		rockchip,pd_idle = <0x40>;
+		rockchip,sr_idle = <0x2>;
+		rockchip,sr_mc_gate_idle = <0x3>;
+		rockchip,srpd_lite_idle	= <0x4>;
+		rockchip,standby_idle = <0x2000>;
+		rockchip,dram_dll_dis_freq = <300>;
+		rockchip,phy_dll_dis_freq = <125>;
+		rockchip,auto_pd_dis_freq = <666>;
+		rockchip,ddr3_odt_dis_freq = <333>;
+		rockchip,ddr3_drv = <DDR3_DS_40ohm>;
+		rockchip,ddr3_odt = <DDR3_ODT_120ohm>;
+		rockchip,phy_ddr3_ca_drv = <PHY_DRV_ODT_40>;
+		rockchip,phy_ddr3_dq_drv = <PHY_DRV_ODT_40>;
+		rockchip,phy_ddr3_odt = <PHY_DRV_ODT_240>;
+		rockchip,lpddr3_odt_dis_freq = <333>;
+		rockchip,lpddr3_drv = <LP3_DS_34ohm>;
+		rockchip,lpddr3_odt = <LP3_ODT_240ohm>;
+		rockchip,phy_lpddr3_ca_drv = <PHY_DRV_ODT_40>;
+		rockchip,phy_lpddr3_dq_drv = <PHY_DRV_ODT_40>;
+		rockchip,phy_lpddr3_odt = <PHY_DRV_ODT_240>;
+		rockchip,lpddr4_odt_dis_freq = <333>;
+		rockchip,lpddr4_drv = <LP4_PDDS_60ohm>;
+		rockchip,lpddr4_dq_odt = <LP4_DQ_ODT_40ohm>;
+		rockchip,lpddr4_ca_odt = <LP4_CA_ODT_40ohm>;
+		rockchip,phy_lpddr4_ca_drv = <PHY_DRV_ODT_40>;
+		rockchip,phy_lpddr4_ck_cs_drv = <PHY_DRV_ODT_80>;
+		rockchip,phy_lpddr4_dq_drv = <PHY_DRV_ODT_80>;
+		rockchip,phy_lpddr4_odt = <PHY_DRV_ODT_60>;
+		status = "disabled";
+	};
+
-- 
2.6.6

Re: [PATCH v10 3/5] Documentation: bindings: add dt documentation for rk3399 dmc

[Rob Herring]

On Mon, Sep 05, 2016 at 01:06:09PM +0800, Lin Huang wrote:
> This patch adds the documentation for rockchip rk3399 dmc driver.
> 
> Signed-off-by: Lin Huang <hl@rock-chips.com>
> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
> Changes in v10:

And this is the first I see it?

> - add rockchip prefix in property describe
> 
> Changes in v9:
> - add ddr timing property to node
> 
> Changes in v8:
> - add ddr timing properties
> 
> Changes in v7:
> - None
> 
> Changes in v6:
> -Add more detail in Documentation
> 
> Changes in v5:
> -None
> 
> Changes in v4:
> -None
> 
> Changes in v3:
> -None
> 
> Changes in v2:
> -None 
> 
> Changes in v1:
> -None
>  .../devicetree/bindings/devfreq/rk3399_dmc.txt     | 202 +++++++++++++++++++++
>  1 file changed, 202 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt
> 
> diff --git a/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt b/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt
> new file mode 100644
> index 0000000..84660a3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt
> @@ -0,0 +1,210 @@
> +* Rockchip rk3399 DMC(Dynamic Memory Controller) device
> +
> +Required properties:
> +- compatible:		 Must be "rockchip,rk3399-dmc".
> +- devfreq-events:	 Node to get DDR loading, Refer to
> +			 Documentation/devicetree/bindings/devfreq/
> +			 rockchip-dfi.txt
> +- interrupts:		 The interrupt number to the CPU. The interrupt
> +			 specifier format depends on the interrupt controller.
> +			 It should be DCF interrupts, when DDR dvfs finish,
> +			 it will happen.
> +- clocks:		 Phandles for clock specified in "clock-names" property
> +- clock-names :		 The name of clock used by the DFI, must be
> +			 "pclk_ddr_mon";
> +- operating-points-v2:	 Refer to Documentation/devicetree/bindings/power/opp.txt
> +			 for details.
> +- center-supply:	 DMC supply node.
> +- status:		 Marks the node enabled/disabled.

No need to document this.

> +
> +Following properties are ddr timing:

This is a lot of properties. I would prefer to see SPD data embedded 
into DT if there are overlap in what SPD data defines for settings.

> +
> +- rockchip,dram_speed_bin :	  Value reference include/dt-bindings/clock/ddr.h,

Use '-', not '_' throughout.

> +				  it select ddr3 cl-trp-trcd type, default value
> +				  "DDR3_DEFAULT".it must selected according to
> +				  "Speed Bin" in ddr3 datasheet, DO NOT use
> +				  smaller "Speed Bin" than ddr3 exactly is.
> +
> +- rockchip,pd_idle :		  Config the PD_IDLE value, defined the power-down
> +				  idle period, memories are places into power-down
> +				  mode if bus is idle for PD_IDLE DFI clocks.
> +
> +- rockchip,sr_idle :		  Configure the SR_IDLE value, defined the
> +				  selfrefresh idle period, memories are places
> +				  into self-refresh mode if bus is idle for
> +				  SR_IDLE*1024 DFI clocks (DFI clocks freq is
> +				  half of dram's clocks), defaule value is "0".
> +
> +- rockchip,sr_mc_gate_idle :	  Defined the self-refresh with memory and
> +				  controller clock gating idle period, memories
> +				  are places into self-refresh mode and memory
> +				  controller clock arg gating if bus is idle for
> +				  sr_mc_gate_idle*1024 DFI clocks.
> +
> +- rockchip,srpd_lite_idle :	  Defined the self-refresh power down idle
> +				  period, memories are places into self-refresh
> +				  power down mode if bus is idle for
> +				  srpd_lite_idle*1024 DFI clocks. This parameter
> +				  is for LPDDR4 only.
> +
> +- rockchip,standby_idle :	  Defined the standby idle period, memories are
> +				  places into self-refresh than controller, pi,
> +				  phy and dram clock will gating if bus is idle
> +				  for standby_idle * DFI clocks.
> +
> +- rockchip,dram_dll_disb_freq :  It's defined the DDR3 dll bypass frequency in
> +				  MHz, when ddr freq less than DRAM_DLL_DISB_FREQ,
> +				  ddr3 dll will bypssed note: if dll was bypassed,
> +				  the odt also stop working.
> +
> +- rockchip,phy_dll_disb_freq :	  Defined the PHY dll bypass frequency in
> +				  MHz (Mega Hz), when ddr freq less than
> +				  DRAM_DLL_DISB_FREQ, phy dll will bypssed.
> +				  note: phy dll and phy odt are independent.
> +
> +- rockchip,ddr3_odt_disb_freq :  When dram type is DDR3, this parameter defined

Please group properties that are required and optional, and also group 
by common, DDR3 only, DDR4L only, etc.

> +				  the odt disable frequency in MHz (Mega Hz),
> +				  when ddr frequency less then ddr3_odt_disb_freq,
> +				  the odt on dram side and controller side are
> +				  both disabled.
> +
> +- rockchip,ddr3_drv :		  When dram type is DDR3, this parameter define
> +				  the dram side driver stength in ohm, default
> +				  value is DDR3_DS_40ohm.
> +
> +- rockchip,ddr3_odt :		  When dram type is DDR3, this parameter define
> +				  the dram side ODT stength in ohm, default value
> +				  is DDR3_ODT_120ohm.
> +
> +- rockchip,phy_ddr3_ca_drv :	  When dram type is DDR3, this parameter define
> +				  the phy side CA line(incluing command line,
> +				  address line and clock line) driver strength.
> +				  Default value is PHY_DRV_ODT_40.
> +
> +- rockchip,phy_ddr3_dq_drv :	  When dram type is DDR3, this parameter define
> +				  the phy side DQ line(incluing DQS/DQ/DM line)
> +				  driver strength. default value is PHY_DRV_ODT_40.

You have the same properties, but they just vary by DDR type. Make the 
property names common. 

> +
> +- rockchip,phy_ddr3_odt : 	  When dram type is DDR3, this parameter define the
> +				  phy side odt strength, default value is
> +				  PHY_DRV_ODT_240.
> +
> +- rockchip,lpddr3_odt_disb_freq : When dram type is LPDDR3, this parameter defined
> +				  then odt disable frequency in MHz (Mega Hz),
> +				  when ddr frequency less then ddr3_odt_disb_freq,
> +				  the odt on dram side and controller side are
> +				  both disabled.
> +
> +- rockchip,lpddr3_drv :	  When dram type is LPDDR3, this parameter define
> +				  the dram side driver stength in ohm, default
> +				  value is LP3_DS_34ohm.
> +
> +- rockchip,lpddr3_odt :	  When dram type is LPDDR3, this parameter define
> +				  the dram side ODT stength in ohm, default value
> +				  is LP3_ODT_240ohm.

Is this in ohms or a register value? Please make it in ohms and add a 
-ohms suffix.

> +Example:
> +	dmc_opp_table: dmc_opp_table {
> +		compatible = "operating-points-v2";
> +
> +		opp00 {
> +			opp-hz = /bits/ 64 <300000000>;
> +			opp-microvolt = <900000>;
> +		};
> +		opp01 {
> +			opp-hz = /bits/ 64 <666000000>;
> +			opp-microvolt = <900000>;
> +		};
> +	};
> +
> +	dmc: dmc {
> +		compatible = "rockchip,rk3399-dmc";
> +		devfreq-events = <&dfi>;
> +		interrupts = <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>;
> +		clocks = <&cru SCLK_DDRCLK>;
> +		clock-names = "dmc_clk";
> +		operating-points-v2 = <&dmc_opp_table>;
> +		center-supply = <&ppvar_centerlogic>;
> +		upthreshold = <15>;
> +		downdifferential = <10>;
> +		rockchip,ddr3_speed_bin = <21>;
> +		rockchip,pd_idle = <0x40>;
> +		rockchip,sr_idle = <0x2>;
> +		rockchip,sr_mc_gate_idle = <0x3>;
> +		rockchip,srpd_lite_idle	= <0x4>;
> +		rockchip,standby_idle = <0x2000>;
> +		rockchip,dram_dll_dis_freq = <300>;
> +		rockchip,phy_dll_dis_freq = <125>;
> +		rockchip,auto_pd_dis_freq = <666>;
> +		rockchip,ddr3_odt_dis_freq = <333>;
> +		rockchip,ddr3_drv = <DDR3_DS_40ohm>;
> +		rockchip,ddr3_odt = <DDR3_ODT_120ohm>;
> +		rockchip,phy_ddr3_ca_drv = <PHY_DRV_ODT_40>;
> +		rockchip,phy_ddr3_dq_drv = <PHY_DRV_ODT_40>;
> +		rockchip,phy_ddr3_odt = <PHY_DRV_ODT_240>;
> +		rockchip,lpddr3_odt_dis_freq = <333>;
> +		rockchip,lpddr3_drv = <LP3_DS_34ohm>;
> +		rockchip,lpddr3_odt = <LP3_ODT_240ohm>;
> +		rockchip,phy_lpddr3_ca_drv = <PHY_DRV_ODT_40>;
> +		rockchip,phy_lpddr3_dq_drv = <PHY_DRV_ODT_40>;
> +		rockchip,phy_lpddr3_odt = <PHY_DRV_ODT_240>;
> +		rockchip,lpddr4_odt_dis_freq = <333>;
> +		rockchip,lpddr4_drv = <LP4_PDDS_60ohm>;
> +		rockchip,lpddr4_dq_odt = <LP4_DQ_ODT_40ohm>;
> +		rockchip,lpddr4_ca_odt = <LP4_CA_ODT_40ohm>;
> +		rockchip,phy_lpddr4_ca_drv = <PHY_DRV_ODT_40>;
> +		rockchip,phy_lpddr4_ck_cs_drv = <PHY_DRV_ODT_80>;
> +		rockchip,phy_lpddr4_dq_drv = <PHY_DRV_ODT_80>;
> +		rockchip,phy_lpddr4_odt = <PHY_DRV_ODT_60>;

You have DDR3, LPDDR3 and LPDDR4 all populated at the same time? It 
should be one set at a time.

Rob

[PATCH v10 4/5] PM / devfreq: rockchip: add devfreq driver for rk3399 dmc

[Lin Huang]

base on dfi result, we do ddr frequency scaling, register
dmc driver to devfreq framework, and use simple-ondemand
policy.

Signed-off-by: Lin Huang <hl@rock-chips.com>
Signed-off-by: MyngJoo Ham <myngjoo.ham@samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
---
Changes in v10:
- None

Changes in v9:
- None

Changes in v8:
- None

Changes in v8:
- do not use ddr_timing node, get ddr timing directly

Changes in v7:
- remove a blank line

Changes in v6:
- fix some nit suggest by Chanwoo Choi

Changes in v5:
- improve dmc driver suggest by Chanwoo Choi

Changes in v4:
- use arm_smccc_smc() function talk to bl31
- delete rockchip_dmc.c file and config
- delete dmc_notify
- adjust probe order

Changes in v3:
- operate dram setting through sip call
- imporve set rate flow

Changes in v2:
- None

Changes in v1:
- move dfi controller to event
- fix set voltage sequence when set rate fail
- change Kconfig type from tristate to bool
- move unuse EXPORT_SYMBOL_GPL()

 drivers/devfreq/Kconfig      |  11 +
 drivers/devfreq/Makefile     |   1 +
 drivers/devfreq/rk3399_dmc.c | 480 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 492 insertions(+)
 create mode 100644 drivers/devfreq/rk3399_dmc.c

diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index a5be56e..e848121 100644
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -100,6 +100,17 @@ config ARM_TEGRA_DEVFREQ
          It reads ACTMON counters of memory controllers and adjusts the
          operating frequencies and voltages with OPP support.
 
+config ARM_RK3399_DMC_DEVFREQ
+	tristate "ARM RK3399 DMC DEVFREQ Driver"
+	depends on ARCH_ROCKCHIP
+	select DEVFREQ_EVENT_ROCKCHIP_DFI
+	select DEVFREQ_GOV_SIMPLE_ONDEMAND
+	select PM_OPP
+	help
+          This adds the DEVFREQ driver for the RK3399 DMC(Dynamic Memory Controller).
+          It sets the frequency for the memory controller and reads the usage counts
+          from hardware.
+
 source "drivers/devfreq/event/Kconfig"
 
 endif # PM_DEVFREQ
diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
index 09f11d9..fbff40a 100644
--- a/drivers/devfreq/Makefile
+++ b/drivers/devfreq/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PASSIVE)	+= governor_passive.o
 
 # DEVFREQ Drivers
 obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ)	+= exynos-bus.o
+obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ)	+= rk3399_dmc.o
 obj-$(CONFIG_ARM_TEGRA_DEVFREQ)		+= tegra-devfreq.o
 
 # DEVFREQ Event Drivers
diff --git a/drivers/devfreq/rk3399_dmc.c b/drivers/devfreq/rk3399_dmc.c
new file mode 100644
index 0000000..54d65f2
--- /dev/null
+++ b/drivers/devfreq/rk3399_dmc.c
@@ -0,0 +1,480 @@
+/*
+ * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd.
+ * Author: Lin Huang <hl@rock-chips.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/devfreq.h>
+#include <linux/devfreq-event.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/regulator/consumer.h>
+#include <linux/rwsem.h>
+#include <linux/suspend.h>
+
+#include <soc/rockchip/rockchip_sip.h>
+
+struct dram_timing {
+	unsigned int ddr3_speed_bin;
+	unsigned int pd_idle;
+	unsigned int sr_idle;
+	unsigned int sr_mc_gate_idle;
+	unsigned int srpd_lite_idle;
+	unsigned int standby_idle;
+	unsigned int auto_pd_dis_freq;
+	unsigned int dram_dll_dis_freq;
+	unsigned int phy_dll_dis_freq;
+	unsigned int ddr3_odt_dis_freq;
+	unsigned int ddr3_drv;
+	unsigned int ddr3_odt;
+	unsigned int phy_ddr3_ca_drv;
+	unsigned int phy_ddr3_dq_drv;
+	unsigned int phy_ddr3_odt;
+	unsigned int lpddr3_odt_dis_freq;
+	unsigned int lpddr3_drv;
+	unsigned int lpddr3_odt;
+	unsigned int phy_lpddr3_ca_drv;
+	unsigned int phy_lpddr3_dq_drv;
+	unsigned int phy_lpddr3_odt;
+	unsigned int lpddr4_odt_dis_freq;
+	unsigned int lpddr4_drv;
+	unsigned int lpddr4_dq_odt;
+	unsigned int lpddr4_ca_odt;
+	unsigned int phy_lpddr4_ca_drv;
+	unsigned int phy_lpddr4_ck_cs_drv;
+	unsigned int phy_lpddr4_dq_drv;
+	unsigned int phy_lpddr4_odt;
+};
+
+struct rk3399_dmcfreq {
+	struct device *dev;
+	struct devfreq *devfreq;
+	struct devfreq_simple_ondemand_data ondemand_data;
+	struct clk *dmc_clk;
+	struct devfreq_event_dev *edev;
+	struct mutex lock;
+	struct dram_timing timing;
+
+	/*
+	 * DDR Converser of Frequency (DCF) is used to implement DDR frequency
+	 * conversion without the participation of CPU, we will implement and
+	 * control it in arm trust firmware.
+	 */
+	wait_queue_head_t	wait_dcf_queue;
+	int irq;
+	int wait_dcf_flag;
+	struct regulator *vdd_center;
+	unsigned long rate, target_rate;
+	unsigned long volt, target_volt;
+	struct dev_pm_opp *curr_opp;
+};
+
+static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq,
+				 u32 flags)
+{
+	struct rk3399_dmcfreq *dmcfreq = dev_get_drvdata(dev);
+	struct dev_pm_opp *opp;
+	unsigned long old_clk_rate = dmcfreq->rate;
+	unsigned long target_volt, target_rate;
+	int err;
+
+	rcu_read_lock();
+	opp = devfreq_recommended_opp(dev, freq, flags);
+	if (IS_ERR(opp)) {
+		rcu_read_unlock();
+		return PTR_ERR(opp);
+	}
+
+	target_rate = dev_pm_opp_get_freq(opp);
+	target_volt = dev_pm_opp_get_voltage(opp);
+
+	dmcfreq->rate = dev_pm_opp_get_freq(dmcfreq->curr_opp);
+	dmcfreq->volt = dev_pm_opp_get_voltage(dmcfreq->curr_opp);
+
+	rcu_read_unlock();
+
+	if (dmcfreq->rate == target_rate)
+		return 0;
+
+	mutex_lock(&dmcfreq->lock);
+
+	/*
+	 * If frequency scaling from low to high, adjust voltage first.
+	 * If frequency scaling from high to low, adjust frequency first.
+	 */
+	if (old_clk_rate < target_rate) {
+		err = regulator_set_voltage(dmcfreq->vdd_center, target_volt,
+					    target_volt);
+		if (err) {
+			dev_err(dev, "Cannot to set voltage %lu uV\n",
+				target_volt);
+			goto out;
+		}
+	}
+	dmcfreq->wait_dcf_flag = 1;
+
+	err = clk_set_rate(dmcfreq->dmc_clk, target_rate);
+	if (err) {
+		dev_err(dev, "Cannot to set frequency %lu (%d)\n",
+			target_rate, err);
+		regulator_set_voltage(dmcfreq->vdd_center, dmcfreq->volt,
+				      dmcfreq->volt);
+		goto out;
+	}
+
+	/*
+	 * Wait until bcf irq happen, it means freq scaling finish in
+	 * arm trust firmware, use 100ms as timeout time.
+	 */
+	if (!wait_event_timeout(dmcfreq->wait_dcf_queue,
+				!dmcfreq->wait_dcf_flag, HZ / 10))
+		dev_warn(dev, "Timeout waiting for dcf interrupt\n");
+
+	/*
+	 * Check the dpll rate,
+	 * There only two result we will get,
+	 * 1. Ddr frequency scaling fail, we still get the old rate.
+	 * 2. Ddr frequency scaling sucessful, we get the rate we set.
+	 */
+	dmcfreq->rate = clk_get_rate(dmcfreq->dmc_clk);
+
+	/* If get the incorrect rate, set voltage to old value. */
+	if (dmcfreq->rate != target_rate) {
+		dev_err(dev, "Get wrong ddr frequency, Request frequency %lu,\
+			Current frequency %lu\n", target_rate, dmcfreq->rate);
+		regulator_set_voltage(dmcfreq->vdd_center, dmcfreq->volt,
+				      dmcfreq->volt);
+		goto out;
+	} else if (old_clk_rate > target_rate)
+		err = regulator_set_voltage(dmcfreq->vdd_center, target_volt,
+					    target_volt);
+	if (err)
+		dev_err(dev, "Cannot to set vol %lu uV\n", target_volt);
+
+	dmcfreq->curr_opp = opp;
+out:
+	mutex_unlock(&dmcfreq->lock);
+	return err;
+}
+
+static int rk3399_dmcfreq_get_dev_status(struct device *dev,
+					 struct devfreq_dev_status *stat)
+{
+	struct rk3399_dmcfreq *dmcfreq = dev_get_drvdata(dev);
+	struct devfreq_event_data edata;
+	int ret = 0;
+
+	ret = devfreq_event_get_event(dmcfreq->edev, &edata);
+	if (ret < 0)
+		return ret;
+
+	stat->current_frequency = dmcfreq->rate;
+	stat->busy_time = edata.load_count;
+	stat->total_time = edata.total_count;
+
+	return ret;
+}
+
+static int rk3399_dmcfreq_get_cur_freq(struct device *dev, unsigned long *freq)
+{
+	struct rk3399_dmcfreq *dmcfreq = dev_get_drvdata(dev);
+
+	*freq = dmcfreq->rate;
+
+	return 0;
+}
+
+static struct devfreq_dev_profile rk3399_devfreq_dmc_profile = {
+	.polling_ms	= 200,
+	.target		= rk3399_dmcfreq_target,
+	.get_dev_status	= rk3399_dmcfreq_get_dev_status,
+	.get_cur_freq	= rk3399_dmcfreq_get_cur_freq,
+};
+
+static __maybe_unused int rk3399_dmcfreq_suspend(struct device *dev)
+{
+	struct rk3399_dmcfreq *dmcfreq = dev_get_drvdata(dev);
+	int ret = 0;
+
+	ret = devfreq_event_disable_edev(dmcfreq->edev);
+	if (ret < 0) {
+		dev_err(dev, "failed to disable the devfreq-event devices\n");
+		return ret;
+	}
+
+	ret = devfreq_suspend_device(dmcfreq->devfreq);
+	if (ret < 0) {
+		dev_err(dev, "failed to suspend the devfreq devices\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static __maybe_unused int rk3399_dmcfreq_resume(struct device *dev)
+{
+	struct rk3399_dmcfreq *dmcfreq = dev_get_drvdata(dev);
+	int ret = 0;
+
+	ret = devfreq_event_enable_edev(dmcfreq->edev);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable the devfreq-event devices\n");
+		return ret;
+	}
+
+	ret = devfreq_resume_device(dmcfreq->devfreq);
+	if (ret < 0) {
+		dev_err(dev, "failed to resume the devfreq devices\n");
+		return ret;
+	}
+	return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(rk3399_dmcfreq_pm, rk3399_dmcfreq_suspend,
+			 rk3399_dmcfreq_resume);
+
+static irqreturn_t rk3399_dmc_irq(int irq, void *dev_id)
+{
+	struct rk3399_dmcfreq *dmcfreq = dev_id;
+	struct arm_smccc_res res;
+
+	dmcfreq->wait_dcf_flag = 0;
+	wake_up(&dmcfreq->wait_dcf_queue);
+
+	/* Clear the DCF interrupt */
+	arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, 0, 0,
+		      ROCKCHIP_SIP_CONFIG_DRAM_CLR_IRQ,
+		      0, 0, 0, 0, &res);
+
+	return IRQ_HANDLED;
+}
+
+static int of_get_ddr_timings(struct dram_timing *timing,
+			      struct device_node *np)
+{
+	int ret = 0;
+
+	ret = of_property_read_u32(np, "rockchip,ddr3_speed_bin",
+				   &timing->ddr3_speed_bin);
+	ret |= of_property_read_u32(np, "rockchip,pd_idle",
+				    &timing->pd_idle);
+	ret |= of_property_read_u32(np, "rockchip,sr_idle",
+				    &timing->sr_idle);
+	ret |= of_property_read_u32(np, "rockchip,sr_mc_gate_idle",
+				    &timing->sr_mc_gate_idle);
+	ret |= of_property_read_u32(np, "rockchip,srpd_lite_idle",
+				    &timing->srpd_lite_idle);
+	ret |= of_property_read_u32(np, "rockchip,standby_idle",
+				    &timing->standby_idle);
+	ret |= of_property_read_u32(np, "rockchip,auto_pd_dis_freq",
+				    &timing->auto_pd_dis_freq);
+	ret |= of_property_read_u32(np, "rockchip,dram_dll_dis_freq",
+				    &timing->dram_dll_dis_freq);
+	ret |= of_property_read_u32(np, "rockchip,phy_dll_dis_freq",
+				    &timing->phy_dll_dis_freq);
+	ret |= of_property_read_u32(np, "rockchip,ddr3_odt_dis_freq",
+				    &timing->ddr3_odt_dis_freq);
+	ret |= of_property_read_u32(np, "rockchip,ddr3_drv",
+				    &timing->ddr3_drv);
+	ret |= of_property_read_u32(np, "rockchip,ddr3_odt",
+				    &timing->ddr3_odt);
+	ret |= of_property_read_u32(np, "rockchip,phy_ddr3_ca_drv",
+				    &timing->phy_ddr3_ca_drv);
+	ret |= of_property_read_u32(np, "rockchip,phy_ddr3_dq_drv",
+				    &timing->phy_ddr3_dq_drv);
+	ret |= of_property_read_u32(np, "rockchip,phy_ddr3_odt",
+				    &timing->phy_ddr3_odt);
+	ret |= of_property_read_u32(np, "rockchip,lpddr3_odt_dis_freq",
+				    &timing->lpddr3_odt_dis_freq);
+	ret |= of_property_read_u32(np, "rockchip,lpddr3_drv",
+				    &timing->lpddr3_drv);
+	ret |= of_property_read_u32(np, "rockchip,lpddr3_odt",
+				    &timing->lpddr3_odt);
+	ret |= of_property_read_u32(np, "rockchip,phy_lpddr3_ca_drv",
+				    &timing->phy_lpddr3_ca_drv);
+	ret |= of_property_read_u32(np, "rockchip,phy_lpddr3_dq_drv",
+				    &timing->phy_lpddr3_dq_drv);
+	ret |= of_property_read_u32(np, "rockchip,phy_lpddr3_odt",
+				    &timing->phy_lpddr3_odt);
+	ret |= of_property_read_u32(np, "rockchip,lpddr4_odt_dis_freq",
+				    &timing->lpddr4_odt_dis_freq);
+	ret |= of_property_read_u32(np, "rockchip,lpddr4_drv",
+				    &timing->lpddr4_drv);
+	ret |= of_property_read_u32(np, "rockchip,lpddr4_dq_odt",
+				    &timing->lpddr4_dq_odt);
+	ret |= of_property_read_u32(np, "rockchip,lpddr4_ca_odt",
+				    &timing->lpddr4_ca_odt);
+	ret |= of_property_read_u32(np, "rockchip,phy_lpddr4_ca_drv",
+				    &timing->phy_lpddr4_ca_drv);
+	ret |= of_property_read_u32(np, "rockchip,phy_lpddr4_ck_cs_drv",
+				    &timing->phy_lpddr4_ck_cs_drv);
+	ret |= of_property_read_u32(np, "rockchip,phy_lpddr4_dq_drv",
+				    &timing->phy_lpddr4_dq_drv);
+	ret |= of_property_read_u32(np, "rockchip,phy_lpddr4_odt",
+				    &timing->phy_lpddr4_odt);
+
+	return ret;
+}
+
+static int rk3399_dmcfreq_probe(struct platform_device *pdev)
+{
+	struct arm_smccc_res res;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = pdev->dev.of_node;
+	struct rk3399_dmcfreq *data;
+	int ret, irq, index, size;
+	uint32_t *timing;
+	struct dev_pm_opp *opp;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "Cannot get the dmc interrupt resource\n");
+		return -EINVAL;
+	}
+	data = devm_kzalloc(dev, sizeof(struct rk3399_dmcfreq), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	mutex_init(&data->lock);
+
+	data->vdd_center = devm_regulator_get(dev, "center");
+	if (IS_ERR(data->vdd_center)) {
+		dev_err(dev, "Cannot get the regulator \"center\"\n");
+		return PTR_ERR(data->vdd_center);
+	}
+
+	data->dmc_clk = devm_clk_get(dev, "dmc_clk");
+	if (IS_ERR(data->dmc_clk)) {
+		dev_err(dev, "Cannot get the clk dmc_clk\n");
+		return PTR_ERR(data->dmc_clk);
+	};
+
+	data->irq = irq;
+	ret = devm_request_irq(dev, irq, rk3399_dmc_irq, 0,
+			       dev_name(dev), data);
+	if (ret) {
+		dev_err(dev, "Failed to request dmc irq: %d\n", ret);
+		return ret;
+	}
+
+	init_waitqueue_head(&data->wait_dcf_queue);
+	data->wait_dcf_flag = 0;
+
+	data->edev = devfreq_event_get_edev_by_phandle(dev, 0);
+	if (IS_ERR(data->edev))
+		return -EPROBE_DEFER;
+
+	ret = devfreq_event_enable_edev(data->edev);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable devfreq-event devices\n");
+		return ret;
+	}
+
+	/*
+	 * Get dram timing and pass it to arm trust firmware,
+	 * the dram drvier in arm trust firmware will get these
+	 * timing and to do dram initial.
+	 */
+	if (!of_get_ddr_timings(&data->timing, np)) {
+		timing = &data->timing.ddr3_speed_bin;
+		size = sizeof(struct dram_timing) / 4;
+		for (index = 0; index < size; index++) {
+			arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, *timing++, index,
+				      ROCKCHIP_SIP_CONFIG_DRAM_SET_PARAM,
+				      0, 0, 0, 0, &res);
+			if (res.a0) {
+				dev_err(dev, "Failed to set dram param: %ld\n",
+					res.a0);
+				return -EINVAL;
+			}
+		}
+	}
+
+	arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, 0, 0,
+		      ROCKCHIP_SIP_CONFIG_DRAM_INIT,
+		      0, 0, 0, 0, &res);
+
+	/*
+	 * We add a devfreq driver to our parent since it has a device tree node
+	 * with operating points.
+	 */
+	if (dev_pm_opp_of_add_table(dev)) {
+		dev_err(dev, "Invalid operating-points in device tree.\n");
+		rcu_read_unlock();
+		return -EINVAL;
+	}
+
+	of_property_read_u32(np, "upthreshold",
+			     &data->ondemand_data.upthreshold);
+	of_property_read_u32(np, "downdifferential",
+			     &data->ondemand_data.downdifferential);
+
+	data->rate = clk_get_rate(data->dmc_clk);
+
+	rcu_read_lock();
+	opp = devfreq_recommended_opp(dev, &data->rate, 0);
+	if (IS_ERR(opp)) {
+		rcu_read_unlock();
+		return PTR_ERR(opp);
+	}
+	rcu_read_unlock();
+	data->curr_opp = opp;
+
+	rk3399_devfreq_dmc_profile.initial_freq = data->rate;
+
+	data->devfreq = devfreq_add_device(dev,
+					   &rk3399_devfreq_dmc_profile,
+					   "simple_ondemand",
+					   &data->ondemand_data);
+	if (IS_ERR(data->devfreq))
+		return PTR_ERR(data->devfreq);
+	devm_devfreq_register_opp_notifier(dev, data->devfreq);
+
+	data->dev = dev;
+	platform_set_drvdata(pdev, data);
+
+	return 0;
+}
+
+static int rk3399_dmcfreq_remove(struct platform_device *pdev)
+{
+	struct rk3399_dmcfreq *dmcfreq = platform_get_drvdata(pdev);
+
+	regulator_put(dmcfreq->vdd_center);
+
+	return 0;
+}
+
+static const struct of_device_id rk3399dmc_devfreq_of_match[] = {
+	{ .compatible = "rockchip,rk3399-dmc" },
+	{ },
+};
+
+static struct platform_driver rk3399_dmcfreq_driver = {
+	.probe	= rk3399_dmcfreq_probe,
+	.remove	= rk3399_dmcfreq_remove,
+	.driver = {
+		.name	= "rk3399-dmc-freq",
+		.pm	= &rk3399_dmcfreq_pm,
+		.of_match_table = rk3399dmc_devfreq_of_match,
+	},
+};
+module_platform_driver(rk3399_dmcfreq_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Lin Huang <hl@rock-chips.com>");
+MODULE_DESCRIPTION("RK3399 dmcfreq driver with devfreq framework");
-- 
2.6.6

[PATCH v10 5/5] drm/rockchip: Add dmc notifier in vop driver

[Lin Huang]

when in ddr frequency scaling process, vop can not do enable or
disable operation, since in dcf we check vop clock to see whether
vop work. If vop work, dcf do ddr frequency scaling when vop
in vblank status, and we need to read vop register to check whether
vop go into vblank status. If vop not work, dcf can do ddr frequency
any time. So when do ddr frequency scaling, you disabled or enable
vop, there may two bad thing happen: 1, the panel flicker(when vop from
disable status change to enable). 2, kernel hang (when vop from enable
status change to disable, dcf need to read vblank status, but if you disable
vop clock, it can not get the status, it will lead soc dead) So we need
register to devfreq notifier, and we can get the dmc status. Also, when
there have two vop enabled, we need to disable dmc, since dcf only base
on one vop vblank time, so the other panel will flicker when do ddr
frequency scaling.

Signed-off-by: Lin Huang <hl@rock-chips.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
---
Changes in v10:
- None

Changes in v9:
- None

Changes in v8:
- None

Changes in v7:
- None

Changes in v6:
- fix a build error

Changes in v5:
- improve some nits

Changes in v4:
- register notifier to devfreq_register_notifier
- use DEVFREQ_PRECHANGE and DEVFREQ_POSTCHANGE to get dmc status
- when two vop enable, disable dmc
- when two vop back to one vop, enable dmc

Changes in v3:
- when do vop eanble/disable, dmc will wait until it finish

Changes in v2:
- None

Changes in v1:
- use wait_event instead usleep

 drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 116 ++++++++++++++++++++++++++++
 1 file changed, 116 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index efbc41a..a73f3aa 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -19,6 +19,8 @@
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_plane_helper.h>
 
+#include <linux/devfreq.h>
+#include <linux/devfreq-event.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
@@ -118,6 +120,13 @@ struct vop {
 
 	const struct vop_data *data;
 
+	struct devfreq *devfreq;
+	struct devfreq_event_dev *devfreq_event_dev;
+	struct notifier_block dmc_nb;
+	int dmc_in_process;
+	int vop_switch_status;
+	wait_queue_head_t wait_dmc_queue;
+	wait_queue_head_t wait_vop_switch_queue;
 	uint32_t *regsbak;
 	void __iomem *regs;
 
@@ -428,11 +437,47 @@ static void vop_dsp_hold_valid_irq_disable(struct vop *vop)
 	spin_unlock_irqrestore(&vop->irq_lock, flags);
 }
 
+static int dmc_notify(struct notifier_block *nb, unsigned long event,
+		      void *data)
+{
+	struct vop *vop = container_of(nb, struct vop, dmc_nb);
+
+	if (event == DEVFREQ_PRECHANGE) {
+		/*
+		 * check if vop in enable or disable process,
+		 * if yes, wait until it finishes, use 200ms as
+		 * timeout.
+		 */
+		if (!wait_event_timeout(vop->wait_vop_switch_queue,
+					!vop->vop_switch_status, HZ / 5))
+			dev_warn(vop->dev,
+				 "Timeout waiting for vop swtich status\n");
+		vop->dmc_in_process = 1;
+	} else if (event == DEVFREQ_POSTCHANGE) {
+		vop->dmc_in_process = 0;
+		wake_up(&vop->wait_dmc_queue);
+	}
+
+	return NOTIFY_OK;
+}
+
 static int vop_enable(struct drm_crtc *crtc)
 {
 	struct vop *vop = to_vop(crtc);
+	int num_enabled_crtc = 0;
 	int ret;
 
+	/*
+	 * if in dmc scaling frequency process, wait until it finishes
+	 * use 200ms as timeout time.
+	 */
+	if (!wait_event_timeout(vop->wait_dmc_queue,
+				!vop->dmc_in_process, HZ / 5))
+		dev_warn(vop->dev,
+			 "Timeout waiting for dmc when vop enable\n");
+
+	vop->vop_switch_status = 1;
+
 	ret = pm_runtime_get_sync(vop->dev);
 	if (ret < 0) {
 		dev_err(vop->dev, "failed to get pm runtime: %d\n", ret);
@@ -479,6 +524,21 @@ static int vop_enable(struct drm_crtc *crtc)
 
 	drm_crtc_vblank_on(crtc);
 
+	vop->vop_switch_status = 0;
+	wake_up(&vop->wait_vop_switch_queue);
+
+	/* check how many VOPs in use now */
+	drm_for_each_crtc(crtc, vop->drm_dev) {
+		if (crtc->state->enable)
+			num_enabled_crtc++;
+	}
+
+	/* if enable two vop, need to disable dmc */
+	if ((num_enabled_crtc > 1) && vop->devfreq) {
+		if (vop->devfreq_event_dev)
+			devfreq_event_disable_edev(vop->devfreq_event_dev);
+		devfreq_suspend_device(vop->devfreq);
+	}
 	return 0;
 
 err_disable_aclk:
@@ -489,17 +549,31 @@ err_disable_hclk:
 	clk_disable(vop->hclk);
 err_put_pm_runtime:
 	pm_runtime_put_sync(vop->dev);
+	vop->vop_switch_status = 0;
+	wake_up(&vop->wait_vop_switch_queue);
 	return ret;
 }
 
 static void vop_crtc_disable(struct drm_crtc *crtc)
 {
 	struct vop *vop = to_vop(crtc);
+	int num_enabled_crtc = 0;
 	int i;
 
 	WARN_ON(vop->event);
 
 	/*
+	 * if in dmc scaling frequency process, wait until it finish
+	 * use 200ms as timeout time.
+	 */
+	if (!wait_event_timeout(vop->wait_dmc_queue,
+				!vop->dmc_in_process, HZ / 5))
+		dev_warn(vop->dev,
+			 "Timeout waiting for dmc when vop disable\n");
+
+	vop->vop_switch_status = 1;
+
+	/*
 	 * We need to make sure that all windows are disabled before we
 	 * disable that crtc. Otherwise we might try to scan from a destroyed
 	 * buffer later.
@@ -555,6 +629,24 @@ static void vop_crtc_disable(struct drm_crtc *crtc)
 		spin_unlock_irq(&crtc->dev->event_lock);
 
 		crtc->state->event = NULL;
+
+	vop->vop_switch_status = 0;
+	wake_up(&vop->wait_vop_switch_queue);
+
+	/* check how many VOPs in use now */
+	drm_for_each_crtc(crtc, vop->drm_dev) {
+		if (crtc->state->enable)
+			num_enabled_crtc++;
+	}
+
+	/*
+	 * if num_enabled_crtc = 1 now, it means 2 vop enabled
+	 * change to 1 vop enabled  need to enable dmc again.
+	 */
+	if ((num_enabled_crtc == 1) && vop->devfreq) {
+		if (vop->devfreq_event_dev)
+			devfreq_event_enable_edev(vop->devfreq_event_dev);
+		devfreq_resume_device(vop->devfreq);
 	}
 }
 
@@ -1413,6 +1505,8 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
 	struct drm_device *drm_dev = data;
 	struct vop *vop;
 	struct resource *res;
+	struct devfreq *devfreq;
+	struct devfreq_event_dev *event_dev;
 	size_t alloc_size;
 	int ret, irq;
 
@@ -1474,6 +1568,28 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
 		return ret;
 
 	pm_runtime_enable(&pdev->dev);
+
+	init_waitqueue_head(&vop->wait_vop_switch_queue);
+	vop->vop_switch_status = 0;
+	init_waitqueue_head(&vop->wait_dmc_queue);
+	vop->dmc_in_process = 0;
+
+	devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
+	if (IS_ERR(devfreq))
+		goto out;
+
+	vop->devfreq = devfreq;
+	vop->dmc_nb.notifier_call = dmc_notify;
+	devfreq_register_notifier(vop->devfreq, &vop->dmc_nb,
+				  DEVFREQ_TRANSITION_NOTIFIER);
+
+	event_dev = devfreq_event_get_edev_by_phandle(vop->devfreq->dev.parent,
+						      0);
+	if (IS_ERR(event_dev))
+		goto out;
+
+	vop->devfreq_event_dev = event_dev;
+out:
 	return 0;
 }
 
-- 
2.6.6

Re: [PATCH v10 5/5] drm/rockchip: Add dmc notifier in vop driver

[kbuild test robot]

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Hi Lin,

[auto build test ERROR on next-20160825]
[cannot apply to rockchip/for-next devfreq/for-rafael linus/master v4.8-rc5 v4.8-rc4 v4.8-rc3 v4.8-rc5]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
[Suggest to use git(>=2.9.0) format-patch --base=<commit> (or --base=auto for convenience) to record what (public, well-known) commit your patch series was built on]
[Check https://git-scm.com/docs/git-format-patch for more information]

url:    https://github.com/0day-ci/linux/commits/Lin-Huang/rk3399-support-ddr-frequency-scaling/20160905-131110
config: arm-multi_v7_defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 5.4.0-6) 5.4.0 20160609
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=arm 

All errors (new ones prefixed by >>):

   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1124:16: note: (near initialization for 'vop_crtc_helper_funcs.mode_fixup')
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1125:18: error: initializer element is not constant
     .atomic_flush = vop_crtc_atomic_flush,
                     ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1125:18: note: (near initialization for 'vop_crtc_helper_funcs.atomic_flush')
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1126:18: error: initializer element is not constant
     .atomic_begin = vop_crtc_atomic_begin,
                     ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1126:18: note: (near initialization for 'vop_crtc_helper_funcs.atomic_begin')
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1129:13: error: invalid storage class for function 'vop_crtc_destroy'
    static void vop_crtc_destroy(struct drm_crtc *crtc)
                ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1134:13: error: invalid storage class for function 'vop_crtc_reset'
    static void vop_crtc_reset(struct drm_crtc *crtc)
                ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1145:31: error: invalid storage class for function 'vop_crtc_duplicate_state'
    static struct drm_crtc_state *vop_crtc_duplicate_state(struct drm_crtc *crtc)
                                  ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1157:13: error: invalid storage class for function 'vop_crtc_destroy_state'
    static void vop_crtc_destroy_state(struct drm_crtc *crtc,
                ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1169:13: error: initializer element is not constant
     .destroy = vop_crtc_destroy,
                ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1169:13: note: (near initialization for 'vop_crtc_funcs.destroy')
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1170:11: error: initializer element is not constant
     .reset = vop_crtc_reset,
              ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1170:11: note: (near initialization for 'vop_crtc_funcs.reset')
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1171:28: error: initializer element is not constant
     .atomic_duplicate_state = vop_crtc_duplicate_state,
                               ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1171:28: note: (near initialization for 'vop_crtc_funcs.atomic_duplicate_state')
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1172:26: error: initializer element is not constant
     .atomic_destroy_state = vop_crtc_destroy_state,
                             ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1172:26: note: (near initialization for 'vop_crtc_funcs.atomic_destroy_state')
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1175:13: error: invalid storage class for function 'vop_win_pending_is_complete'
    static bool vop_win_pending_is_complete(struct vop_win *vop_win)
                ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1187:13: error: invalid storage class for function 'vop_handle_vblank'
    static void vop_handle_vblank(struct vop *vop)
                ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1213:20: error: invalid storage class for function 'vop_isr'
    static irqreturn_t vop_isr(int irq, void *data)
                       ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1259:12: error: invalid storage class for function 'vop_create_crtc'
    static int vop_create_crtc(struct vop *vop)
               ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1359:13: error: invalid storage class for function 'vop_destroy_crtc'
    static void vop_destroy_crtc(struct vop *vop)
                ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1387:12: error: invalid storage class for function 'vop_initial'
    static int vop_initial(struct vop *vop)
               ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1487:13: error: invalid storage class for function 'vop_win_init'
    static void vop_win_init(struct vop *vop)
                ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1501:12: error: invalid storage class for function 'vop_bind'
    static int vop_bind(struct device *dev, struct device *master, void *data)
               ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1596:13: error: invalid storage class for function 'vop_unbind'
    static void vop_unbind(struct device *dev, struct device *master, void *data)
                ^
   In file included from include/linux/linkage.h:6:0,
                    from include/linux/kernel.h:6,
                    from include/linux/list.h:8,
                    from include/linux/agp_backend.h:33,
                    from include/drm/drmP.h:35,
                    from drivers/gpu/drm/rockchip/rockchip_drm_vop.c:16:
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1608:19: error: extern declaration of 'vop_component_ops' follows declaration with no linkage
    EXPORT_SYMBOL_GPL(vop_component_ops);
                      ^
   include/linux/export.h:57:21: note: in definition of macro '___EXPORT_SYMBOL'
     extern typeof(sym) sym;     \
                        ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1608:1: note: in expansion of macro 'EXPORT_SYMBOL_GPL'
    EXPORT_SYMBOL_GPL(vop_component_ops);
    ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1604:28: note: previous definition of 'vop_component_ops' was here
    const struct component_ops vop_component_ops = {
                               ^
   In file included from include/linux/linkage.h:6:0,
                    from include/linux/kernel.h:6,
                    from include/linux/list.h:8,
                    from include/linux/agp_backend.h:33,
                    from include/drm/drmP.h:35,
                    from drivers/gpu/drm/rockchip/rockchip_drm_vop.c:16:
   include/linux/export.h:63:25: warning: '__used__' attribute ignored [-Wattributes]
     __visible const struct kernel_symbol __ksymtab_##sym \
                            ^
   include/linux/export.h:94:25: note: in expansion of macro '___EXPORT_SYMBOL'
    #define __EXPORT_SYMBOL ___EXPORT_SYMBOL
                            ^
   include/linux/export.h:101:2: note: in expansion of macro '__EXPORT_SYMBOL'
     __EXPORT_SYMBOL(sym, "_gpl")
     ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1608:1: note: in expansion of macro 'EXPORT_SYMBOL_GPL'
    EXPORT_SYMBOL_GPL(vop_component_ops);
    ^
>> include/linux/export.h:63:39: error: section attribute cannot be specified for local variables
     __visible const struct kernel_symbol __ksymtab_##sym \
                                          ^
   include/linux/export.h:94:25: note: in expansion of macro '___EXPORT_SYMBOL'
    #define __EXPORT_SYMBOL ___EXPORT_SYMBOL
                            ^
   include/linux/export.h:101:2: note: in expansion of macro '__EXPORT_SYMBOL'
     __EXPORT_SYMBOL(sym, "_gpl")
     ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1608:1: note: in expansion of macro 'EXPORT_SYMBOL_GPL'
    EXPORT_SYMBOL_GPL(vop_component_ops);
    ^
   include/linux/export.h:63:25: warning: 'externally_visible' attribute have effect only on public objects [-Wattributes]
     __visible const struct kernel_symbol __ksymtab_##sym \
                            ^
   include/linux/export.h:94:25: note: in expansion of macro '___EXPORT_SYMBOL'
    #define __EXPORT_SYMBOL ___EXPORT_SYMBOL
                            ^
   include/linux/export.h:101:2: note: in expansion of macro '__EXPORT_SYMBOL'
     __EXPORT_SYMBOL(sym, "_gpl")
     ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1608:1: note: in expansion of macro 'EXPORT_SYMBOL_GPL'
    EXPORT_SYMBOL_GPL(vop_component_ops);
    ^
   include/linux/export.h:63:39: error: declaration of '__ksymtab_vop_component_ops' with no linkage follows extern declaration
     __visible const struct kernel_symbol __ksymtab_##sym \
                                          ^
   include/linux/export.h:94:25: note: in expansion of macro '___EXPORT_SYMBOL'
    #define __EXPORT_SYMBOL ___EXPORT_SYMBOL
                            ^
   include/linux/export.h:101:2: note: in expansion of macro '__EXPORT_SYMBOL'
     __EXPORT_SYMBOL(sym, "_gpl")
     ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1608:1: note: in expansion of macro 'EXPORT_SYMBOL_GPL'
    EXPORT_SYMBOL_GPL(vop_component_ops);
    ^
   include/linux/export.h:62:36: note: previous declaration of '__ksymtab_vop_component_ops' was here
     extern const struct kernel_symbol __ksymtab_##sym; \
                                       ^
   include/linux/export.h:94:25: note: in expansion of macro '___EXPORT_SYMBOL'
    #define __EXPORT_SYMBOL ___EXPORT_SYMBOL
                            ^
   include/linux/export.h:101:2: note: in expansion of macro '__EXPORT_SYMBOL'
     __EXPORT_SYMBOL(sym, "_gpl")
     ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1608:1: note: in expansion of macro 'EXPORT_SYMBOL_GPL'
    EXPORT_SYMBOL_GPL(vop_component_ops);
    ^
>> include/linux/export.h:63:25: error: expected declaration or statement at end of input
     __visible const struct kernel_symbol __ksymtab_##sym \
                            ^
   include/linux/export.h:94:25: note: in expansion of macro '___EXPORT_SYMBOL'
    #define __EXPORT_SYMBOL ___EXPORT_SYMBOL
                            ^
   include/linux/export.h:101:2: note: in expansion of macro '__EXPORT_SYMBOL'
     __EXPORT_SYMBOL(sym, "_gpl")
     ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:1608:1: note: in expansion of macro 'EXPORT_SYMBOL_GPL'
    EXPORT_SYMBOL_GPL(vop_component_ops);
    ^
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c: At top level:
   drivers/gpu/drm/rockchip/rockchip_drm_vop.c:557:13: warning: 'vop_crtc_disable' defined but not used [-Wunused-function]
    static void vop_crtc_disable(struct drm_crtc *crtc)
                ^

vim +63 include/linux/export.h

f5016932 Paul Gortmaker  2011-05-23  57  	extern typeof(sym) sym;					\
f5016932 Paul Gortmaker  2011-05-23  58  	__CRC_SYMBOL(sym, sec)					\
f5016932 Paul Gortmaker  2011-05-23  59  	static const char __kstrtab_##sym[]			\
f5016932 Paul Gortmaker  2011-05-23  60  	__attribute__((section("__ksymtab_strings"), aligned(1))) \
b92021b0 Rusty Russell   2013-03-15  61  	= VMLINUX_SYMBOL_STR(sym);				\
7b4ec8dd Johannes Berg   2014-01-16  62  	extern const struct kernel_symbol __ksymtab_##sym;	\
e0f244c6 Andi Kleen      2013-10-23 @63  	__visible const struct kernel_symbol __ksymtab_##sym	\
f5016932 Paul Gortmaker  2011-05-23  64  	__used							\
f5016932 Paul Gortmaker  2011-05-23  65  	__attribute__((section("___ksymtab" sec "+" #sym), unused))	\
f5016932 Paul Gortmaker  2011-05-23  66  	= { (unsigned long)&sym, __kstrtab_##sym }
f5016932 Paul Gortmaker  2011-05-23  67  
c1a95fda Nicolas Pitre   2016-01-22  68  #if defined(__KSYM_DEPS__)
c1a95fda Nicolas Pitre   2016-01-22  69  
c1a95fda Nicolas Pitre   2016-01-22  70  /*
c1a95fda Nicolas Pitre   2016-01-22  71   * For fine grained build dependencies, we want to tell the build system
c1a95fda Nicolas Pitre   2016-01-22  72   * about each possible exported symbol even if they're not actually exported.
c1a95fda Nicolas Pitre   2016-01-22  73   * We use a string pattern that is unlikely to be valid code that the build
c1a95fda Nicolas Pitre   2016-01-22  74   * system filters out from the preprocessor output (see ksym_dep_filter
c1a95fda Nicolas Pitre   2016-01-22  75   * in scripts/Kbuild.include).
c1a95fda Nicolas Pitre   2016-01-22  76   */
c1a95fda Nicolas Pitre   2016-01-22  77  #define __EXPORT_SYMBOL(sym, sec)	=== __KSYM_##sym ===
c1a95fda Nicolas Pitre   2016-01-22  78  
c1a95fda Nicolas Pitre   2016-01-22  79  #elif defined(CONFIG_TRIM_UNUSED_KSYMS)
f2355416 Nicolas Pitre   2016-01-22  80  
f2355416 Nicolas Pitre   2016-01-22  81  #include <linux/kconfig.h>
f2355416 Nicolas Pitre   2016-01-22  82  #include <generated/autoksyms.h>
f2355416 Nicolas Pitre   2016-01-22  83  
f2355416 Nicolas Pitre   2016-01-22  84  #define __EXPORT_SYMBOL(sym, sec)				\
6023d236 Masahiro Yamada 2016-06-14  85  	__cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
f2355416 Nicolas Pitre   2016-01-22  86  #define __cond_export_sym(sym, sec, conf)			\
f2355416 Nicolas Pitre   2016-01-22  87  	___cond_export_sym(sym, sec, conf)
f2355416 Nicolas Pitre   2016-01-22  88  #define ___cond_export_sym(sym, sec, enabled)			\
f2355416 Nicolas Pitre   2016-01-22  89  	__cond_export_sym_##enabled(sym, sec)
f2355416 Nicolas Pitre   2016-01-22  90  #define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
f2355416 Nicolas Pitre   2016-01-22  91  #define __cond_export_sym_0(sym, sec) /* nothing */
f2355416 Nicolas Pitre   2016-01-22  92  
f2355416 Nicolas Pitre   2016-01-22  93  #else
f2355416 Nicolas Pitre   2016-01-22 @94  #define __EXPORT_SYMBOL ___EXPORT_SYMBOL
f2355416 Nicolas Pitre   2016-01-22  95  #endif
f2355416 Nicolas Pitre   2016-01-22  96  
f5016932 Paul Gortmaker  2011-05-23  97  #define EXPORT_SYMBOL(sym)					\

:::::: The code at line 63 was first introduced by commit
:::::: e0f244c63fc9d192dfd399cc2677bbdca61994b1 asmlinkage, module: Make ksymtab and kcrctab symbols and __this_module __visible

:::::: TO: Andi Kleen <ak@linux.intel.com>
:::::: CC: Rusty Russell <rusty@rustcorp.com.au>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 38827 bytes --]

Re: [PATCH v10 5/5] drm/rockchip: Add dmc notifier in vop driver

[Sean Paul]

On Mon, Sep 5, 2016 at 1:06 AM, Lin Huang <hl@rock-chips.com> wrote:
> when in ddr frequency scaling process, vop can not do enable or
> disable operation, since in dcf we check vop clock to see whether
> vop work. If vop work, dcf do ddr frequency scaling when vop
> in vblank status, and we need to read vop register to check whether
> vop go into vblank status. If vop not work, dcf can do ddr frequency
> any time. So when do ddr frequency scaling, you disabled or enable
> vop, there may two bad thing happen: 1, the panel flicker(when vop from
> disable status change to enable). 2, kernel hang (when vop from enable
> status change to disable, dcf need to read vblank status, but if you disable
> vop clock, it can not get the status, it will lead soc dead) So we need
> register to devfreq notifier, and we can get the dmc status. Also, when
> there have two vop enabled, we need to disable dmc, since dcf only base
> on one vop vblank time, so the other panel will flicker when do ddr
> frequency scaling.
>
> Signed-off-by: Lin Huang <hl@rock-chips.com>
> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
> Changes in v10:
> - None
>
> Changes in v9:
> - None
>
> Changes in v8:
> - None
>
> Changes in v7:
> - None
>
> Changes in v6:
> - fix a build error
>
> Changes in v5:
> - improve some nits
>
> Changes in v4:
> - register notifier to devfreq_register_notifier
> - use DEVFREQ_PRECHANGE and DEVFREQ_POSTCHANGE to get dmc status
> - when two vop enable, disable dmc
> - when two vop back to one vop, enable dmc
>
> Changes in v3:
> - when do vop eanble/disable, dmc will wait until it finish
>
> Changes in v2:
> - None
>
> Changes in v1:
> - use wait_event instead usleep
>
>  drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 116 ++++++++++++++++++++++++++++
>  1 file changed, 116 insertions(+)
>
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> index efbc41a..a73f3aa 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> @@ -19,6 +19,8 @@
>  #include <drm/drm_crtc_helper.h>
>  #include <drm/drm_plane_helper.h>
>
> +#include <linux/devfreq.h>
> +#include <linux/devfreq-event.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
> @@ -118,6 +120,13 @@ struct vop {
>
>         const struct vop_data *data;
>
> +       struct devfreq *devfreq;
> +       struct devfreq_event_dev *devfreq_event_dev;
> +       struct notifier_block dmc_nb;
> +       int dmc_in_process;
> +       int vop_switch_status;
> +       wait_queue_head_t wait_dmc_queue;
> +       wait_queue_head_t wait_vop_switch_queue;
>         uint32_t *regsbak;
>         void __iomem *regs;
>
> @@ -428,11 +437,47 @@ static void vop_dsp_hold_valid_irq_disable(struct vop *vop)
>         spin_unlock_irqrestore(&vop->irq_lock, flags);
>  }
>
> +static int dmc_notify(struct notifier_block *nb, unsigned long event,
> +                     void *data)
> +{
> +       struct vop *vop = container_of(nb, struct vop, dmc_nb);
> +
> +       if (event == DEVFREQ_PRECHANGE) {
> +               /*
> +                * check if vop in enable or disable process,
> +                * if yes, wait until it finishes, use 200ms as
> +                * timeout.
> +                */
> +               if (!wait_event_timeout(vop->wait_vop_switch_queue,
> +                                       !vop->vop_switch_status, HZ / 5))
> +                       dev_warn(vop->dev,
> +                                "Timeout waiting for vop swtich status\n");
> +               vop->dmc_in_process = 1;
> +       } else if (event == DEVFREQ_POSTCHANGE) {
> +               vop->dmc_in_process = 0;
> +               wake_up(&vop->wait_dmc_queue);
> +       }
> +
> +       return NOTIFY_OK;
> +}
> +
>  static int vop_enable(struct drm_crtc *crtc)
>  {
>         struct vop *vop = to_vop(crtc);
> +       int num_enabled_crtc = 0;
>         int ret;
>
> +       /*
> +        * if in dmc scaling frequency process, wait until it finishes
> +        * use 200ms as timeout time.
> +        */
> +       if (!wait_event_timeout(vop->wait_dmc_queue,
> +                               !vop->dmc_in_process, HZ / 5))
> +               dev_warn(vop->dev,
> +                        "Timeout waiting for dmc when vop enable\n");
> +


This wait_event_timeout code is terribly racey (same goes above and below).


> +       vop->vop_switch_status = 1;
> +
>         ret = pm_runtime_get_sync(vop->dev);
>         if (ret < 0) {
>                 dev_err(vop->dev, "failed to get pm runtime: %d\n", ret);
> @@ -479,6 +524,21 @@ static int vop_enable(struct drm_crtc *crtc)
>
>         drm_crtc_vblank_on(crtc);
>
> +       vop->vop_switch_status = 0;
> +       wake_up(&vop->wait_vop_switch_queue);
> +
> +       /* check how many VOPs in use now */
> +       drm_for_each_crtc(crtc, vop->drm_dev) {
> +               if (crtc->state->enable)

I think you really want to check active, instead of enable.

> +                       num_enabled_crtc++;
> +       }
> +
> +       /* if enable two vop, need to disable dmc */
> +       if ((num_enabled_crtc > 1) && vop->devfreq) {
> +               if (vop->devfreq_event_dev)
> +                       devfreq_event_disable_edev(vop->devfreq_event_dev);
> +               devfreq_suspend_device(vop->devfreq);
> +       }

This really feels like something that should be handled somewhere
else. I don't fully understand how this works, but it seems like this
dependency should be handled where it actually matters, rather than
building in a seemingly arbitrary restriction in the vop driver.

Even if this is the best place for it, this needs to be refactored to
eliminate the races that exist now.

Sean

>         return 0;
>
>  err_disable_aclk:
> @@ -489,17 +549,31 @@ err_disable_hclk:
>         clk_disable(vop->hclk);
>  err_put_pm_runtime:
>         pm_runtime_put_sync(vop->dev);
> +       vop->vop_switch_status = 0;
> +       wake_up(&vop->wait_vop_switch_queue);
>         return ret;
>  }
>
>  static void vop_crtc_disable(struct drm_crtc *crtc)
>  {
>         struct vop *vop = to_vop(crtc);
> +       int num_enabled_crtc = 0;
>         int i;
>
>         WARN_ON(vop->event);
>
>         /*
> +        * if in dmc scaling frequency process, wait until it finish
> +        * use 200ms as timeout time.
> +        */
> +       if (!wait_event_timeout(vop->wait_dmc_queue,
> +                               !vop->dmc_in_process, HZ / 5))
> +               dev_warn(vop->dev,
> +                        "Timeout waiting for dmc when vop disable\n");
> +
> +       vop->vop_switch_status = 1;
> +
> +       /*
>          * We need to make sure that all windows are disabled before we
>          * disable that crtc. Otherwise we might try to scan from a destroyed
>          * buffer later.
> @@ -555,6 +629,24 @@ static void vop_crtc_disable(struct drm_crtc *crtc)
>                 spin_unlock_irq(&crtc->dev->event_lock);
>
>                 crtc->state->event = NULL;
> +
> +       vop->vop_switch_status = 0;
> +       wake_up(&vop->wait_vop_switch_queue);
> +
> +       /* check how many VOPs in use now */
> +       drm_for_each_crtc(crtc, vop->drm_dev) {
> +               if (crtc->state->enable)
> +                       num_enabled_crtc++;
> +       }
> +
> +       /*
> +        * if num_enabled_crtc = 1 now, it means 2 vop enabled
> +        * change to 1 vop enabled  need to enable dmc again.
> +        */
> +       if ((num_enabled_crtc == 1) && vop->devfreq) {
> +               if (vop->devfreq_event_dev)
> +                       devfreq_event_enable_edev(vop->devfreq_event_dev);
> +               devfreq_resume_device(vop->devfreq);
>         }
>  }
>
> @@ -1413,6 +1505,8 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
>         struct drm_device *drm_dev = data;
>         struct vop *vop;
>         struct resource *res;
> +       struct devfreq *devfreq;
> +       struct devfreq_event_dev *event_dev;
>         size_t alloc_size;
>         int ret, irq;
>
> @@ -1474,6 +1568,28 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
>                 return ret;
>
>         pm_runtime_enable(&pdev->dev);
> +
> +       init_waitqueue_head(&vop->wait_vop_switch_queue);
> +       vop->vop_switch_status = 0;
> +       init_waitqueue_head(&vop->wait_dmc_queue);
> +       vop->dmc_in_process = 0;
> +
> +       devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
> +       if (IS_ERR(devfreq))
> +               goto out;
> +
> +       vop->devfreq = devfreq;
> +       vop->dmc_nb.notifier_call = dmc_notify;
> +       devfreq_register_notifier(vop->devfreq, &vop->dmc_nb,
> +                                 DEVFREQ_TRANSITION_NOTIFIER);
> +
> +       event_dev = devfreq_event_get_edev_by_phandle(vop->devfreq->dev.parent,
> +                                                     0);
> +       if (IS_ERR(event_dev))
> +               goto out;
> +
> +       vop->devfreq_event_dev = event_dev;
> +out:
>         return 0;
>  }
>
> --
> 2.6.6
>

Re: [PATCH v10 5/5] drm/rockchip: Add dmc notifier in vop driver

[hl]

Hi Sean,

On 2016年09月07日 01:18, Sean Paul wrote:
> On Mon, Sep 5, 2016 at 1:06 AM, Lin Huang <hl@rock-chips.com> wrote:
>> when in ddr frequency scaling process, vop can not do enable or
>> disable operation, since in dcf we check vop clock to see whether
>> vop work. If vop work, dcf do ddr frequency scaling when vop
>> in vblank status, and we need to read vop register to check whether
>> vop go into vblank status. If vop not work, dcf can do ddr frequency
>> any time. So when do ddr frequency scaling, you disabled or enable
>> vop, there may two bad thing happen: 1, the panel flicker(when vop from
>> disable status change to enable). 2, kernel hang (when vop from enable
>> status change to disable, dcf need to read vblank status, but if you disable
>> vop clock, it can not get the status, it will lead soc dead) So we need
>> register to devfreq notifier, and we can get the dmc status. Also, when
>> there have two vop enabled, we need to disable dmc, since dcf only base
>> on one vop vblank time, so the other panel will flicker when do ddr
>> frequency scaling.
>>
>> Signed-off-by: Lin Huang <hl@rock-chips.com>
>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
>> ---
>> Changes in v10:
>> - None
>>
>> Changes in v9:
>> - None
>>
>> Changes in v8:
>> - None
>>
>> Changes in v7:
>> - None
>>
>> Changes in v6:
>> - fix a build error
>>
>> Changes in v5:
>> - improve some nits
>>
>> Changes in v4:
>> - register notifier to devfreq_register_notifier
>> - use DEVFREQ_PRECHANGE and DEVFREQ_POSTCHANGE to get dmc status
>> - when two vop enable, disable dmc
>> - when two vop back to one vop, enable dmc
>>
>> Changes in v3:
>> - when do vop eanble/disable, dmc will wait until it finish
>>
>> Changes in v2:
>> - None
>>
>> Changes in v1:
>> - use wait_event instead usleep
>>
>>   drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 116 ++++++++++++++++++++++++++++
>>   1 file changed, 116 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> index efbc41a..a73f3aa 100644
>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> @@ -19,6 +19,8 @@
>>   #include <drm/drm_crtc_helper.h>
>>   #include <drm/drm_plane_helper.h>
>>
>> +#include <linux/devfreq.h>
>> +#include <linux/devfreq-event.h>
>>   #include <linux/kernel.h>
>>   #include <linux/module.h>
>>   #include <linux/platform_device.h>
>> @@ -118,6 +120,13 @@ struct vop {
>>
>>          const struct vop_data *data;
>>
>> +       struct devfreq *devfreq;
>> +       struct devfreq_event_dev *devfreq_event_dev;
>> +       struct notifier_block dmc_nb;
>> +       int dmc_in_process;
>> +       int vop_switch_status;
>> +       wait_queue_head_t wait_dmc_queue;
>> +       wait_queue_head_t wait_vop_switch_queue;
>>          uint32_t *regsbak;
>>          void __iomem *regs;
>>
>> @@ -428,11 +437,47 @@ static void vop_dsp_hold_valid_irq_disable(struct vop *vop)
>>          spin_unlock_irqrestore(&vop->irq_lock, flags);
>>   }
>>
>> +static int dmc_notify(struct notifier_block *nb, unsigned long event,
>> +                     void *data)
>> +{
>> +       struct vop *vop = container_of(nb, struct vop, dmc_nb);
>> +
>> +       if (event == DEVFREQ_PRECHANGE) {
>> +               /*
>> +                * check if vop in enable or disable process,
>> +                * if yes, wait until it finishes, use 200ms as
>> +                * timeout.
>> +                */
>> +               if (!wait_event_timeout(vop->wait_vop_switch_queue,
>> +                                       !vop->vop_switch_status, HZ / 5))
>> +                       dev_warn(vop->dev,
>> +                                "Timeout waiting for vop swtich status\n");
>> +               vop->dmc_in_process = 1;
>> +       } else if (event == DEVFREQ_POSTCHANGE) {
>> +               vop->dmc_in_process = 0;
>> +               wake_up(&vop->wait_dmc_queue);
>> +       }
>> +
>> +       return NOTIFY_OK;
>> +}
>> +
>>   static int vop_enable(struct drm_crtc *crtc)
>>   {
>>          struct vop *vop = to_vop(crtc);
>> +       int num_enabled_crtc = 0;
>>          int ret;
>>
>> +       /*
>> +        * if in dmc scaling frequency process, wait until it finishes
>> +        * use 200ms as timeout time.
>> +        */
>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>> +                               !vop->dmc_in_process, HZ / 5))
>> +               dev_warn(vop->dev,
>> +                        "Timeout waiting for dmc when vop enable\n");
>> +
>
> This wait_event_timeout code is terribly racey (same goes above and below).
   No i use the vop_switch_status and dmc_in_progress to handle the vop 
and dmc racey,
    I assume this can fix the racey now. I do not better a idea now.
>
>
>> +       vop->vop_switch_status = 1;
>> +
>>          ret = pm_runtime_get_sync(vop->dev);
>>          if (ret < 0) {
>>                  dev_err(vop->dev, "failed to get pm runtime: %d\n", ret);
>> @@ -479,6 +524,21 @@ static int vop_enable(struct drm_crtc *crtc)
>>
>>          drm_crtc_vblank_on(crtc);
>>
>> +       vop->vop_switch_status = 0;
>> +       wake_up(&vop->wait_vop_switch_queue);
>> +
>> +       /* check how many VOPs in use now */
>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>> +               if (crtc->state->enable)
> I think you really want to check active, instead of enable.
Okay, i will check it, thanks.
>
>> +                       num_enabled_crtc++;
>> +       }
>> +
>> +       /* if enable two vop, need to disable dmc */
>> +       if ((num_enabled_crtc > 1) && vop->devfreq) {
>> +               if (vop->devfreq_event_dev)
>> +                       devfreq_event_disable_edev(vop->devfreq_event_dev);
>> +               devfreq_suspend_device(vop->devfreq);
>> +       }
> This really feels like something that should be handled somewhere
> else. I don't fully understand how this works, but it seems like this
> dependency should be handled where it actually matters, rather than
> building in a seemingly arbitrary restriction in the vop driver.
>
> Even if this is the best place for it, this needs to be refactored to
> eliminate the races that exist now.
>
> Sean
>
>>          return 0;
>>
>>   err_disable_aclk:
>> @@ -489,17 +549,31 @@ err_disable_hclk:
>>          clk_disable(vop->hclk);
>>   err_put_pm_runtime:
>>          pm_runtime_put_sync(vop->dev);
>> +       vop->vop_switch_status = 0;
>> +       wake_up(&vop->wait_vop_switch_queue);
>>          return ret;
>>   }
>>
>>   static void vop_crtc_disable(struct drm_crtc *crtc)
>>   {
>>          struct vop *vop = to_vop(crtc);
>> +       int num_enabled_crtc = 0;
>>          int i;
>>
>>          WARN_ON(vop->event);
>>
>>          /*
>> +        * if in dmc scaling frequency process, wait until it finish
>> +        * use 200ms as timeout time.
>> +        */
>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>> +                               !vop->dmc_in_process, HZ / 5))
>> +               dev_warn(vop->dev,
>> +                        "Timeout waiting for dmc when vop disable\n");
>> +
>> +       vop->vop_switch_status = 1;
>> +
>> +       /*
>>           * We need to make sure that all windows are disabled before we
>>           * disable that crtc. Otherwise we might try to scan from a destroyed
>>           * buffer later.
>> @@ -555,6 +629,24 @@ static void vop_crtc_disable(struct drm_crtc *crtc)
>>                  spin_unlock_irq(&crtc->dev->event_lock);
>>
>>                  crtc->state->event = NULL;
>> +
>> +       vop->vop_switch_status = 0;
>> +       wake_up(&vop->wait_vop_switch_queue);
>> +
>> +       /* check how many VOPs in use now */
>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>> +               if (crtc->state->enable)
>> +                       num_enabled_crtc++;
>> +       }
>> +
>> +       /*
>> +        * if num_enabled_crtc = 1 now, it means 2 vop enabled
>> +        * change to 1 vop enabled  need to enable dmc again.
>> +        */
>> +       if ((num_enabled_crtc == 1) && vop->devfreq) {
>> +               if (vop->devfreq_event_dev)
>> +                       devfreq_event_enable_edev(vop->devfreq_event_dev);
>> +               devfreq_resume_device(vop->devfreq);
>>          }
>>   }
>>
>> @@ -1413,6 +1505,8 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
>>          struct drm_device *drm_dev = data;
>>          struct vop *vop;
>>          struct resource *res;
>> +       struct devfreq *devfreq;
>> +       struct devfreq_event_dev *event_dev;
>>          size_t alloc_size;
>>          int ret, irq;
>>
>> @@ -1474,6 +1568,28 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
>>                  return ret;
>>
>>          pm_runtime_enable(&pdev->dev);
>> +
>> +       init_waitqueue_head(&vop->wait_vop_switch_queue);
>> +       vop->vop_switch_status = 0;
>> +       init_waitqueue_head(&vop->wait_dmc_queue);
>> +       vop->dmc_in_process = 0;
>> +
>> +       devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
>> +       if (IS_ERR(devfreq))
>> +               goto out;
>> +
>> +       vop->devfreq = devfreq;
>> +       vop->dmc_nb.notifier_call = dmc_notify;
>> +       devfreq_register_notifier(vop->devfreq, &vop->dmc_nb,
>> +                                 DEVFREQ_TRANSITION_NOTIFIER);
>> +
>> +       event_dev = devfreq_event_get_edev_by_phandle(vop->devfreq->dev.parent,
>> +                                                     0);
>> +       if (IS_ERR(event_dev))
>> +               goto out;
>> +
>> +       vop->devfreq_event_dev = event_dev;
>> +out:
>>          return 0;
>>   }
>>
>> --
>> 2.6.6
>>
>
>

-- 
Lin Huang

Re: [PATCH v10 5/5] drm/rockchip: Add dmc notifier in vop driver

[Sean Paul]

On Tue, Sep 6, 2016 at 2:15 PM, hl <hl@rock-chips.com> wrote:
> Hi Sean,
>
>
> On 2016年09月07日 01:18, Sean Paul wrote:
>>
>> On Mon, Sep 5, 2016 at 1:06 AM, Lin Huang <hl@rock-chips.com> wrote:
>>>
>>> when in ddr frequency scaling process, vop can not do enable or
>>> disable operation, since in dcf we check vop clock to see whether
>>> vop work. If vop work, dcf do ddr frequency scaling when vop
>>> in vblank status, and we need to read vop register to check whether
>>> vop go into vblank status. If vop not work, dcf can do ddr frequency
>>> any time. So when do ddr frequency scaling, you disabled or enable
>>> vop, there may two bad thing happen: 1, the panel flicker(when vop from
>>> disable status change to enable). 2, kernel hang (when vop from enable
>>> status change to disable, dcf need to read vblank status, but if you
>>> disable
>>> vop clock, it can not get the status, it will lead soc dead) So we need
>>> register to devfreq notifier, and we can get the dmc status. Also, when
>>> there have two vop enabled, we need to disable dmc, since dcf only base
>>> on one vop vblank time, so the other panel will flicker when do ddr
>>> frequency scaling.
>>>
>>> Signed-off-by: Lin Huang <hl@rock-chips.com>
>>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
>>> ---
>>> Changes in v10:
>>> - None
>>>
>>> Changes in v9:
>>> - None
>>>
>>> Changes in v8:
>>> - None
>>>
>>> Changes in v7:
>>> - None
>>>
>>> Changes in v6:
>>> - fix a build error
>>>
>>> Changes in v5:
>>> - improve some nits
>>>
>>> Changes in v4:
>>> - register notifier to devfreq_register_notifier
>>> - use DEVFREQ_PRECHANGE and DEVFREQ_POSTCHANGE to get dmc status
>>> - when two vop enable, disable dmc
>>> - when two vop back to one vop, enable dmc
>>>
>>> Changes in v3:
>>> - when do vop eanble/disable, dmc will wait until it finish
>>>
>>> Changes in v2:
>>> - None
>>>
>>> Changes in v1:
>>> - use wait_event instead usleep
>>>
>>>   drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 116
>>> ++++++++++++++++++++++++++++
>>>   1 file changed, 116 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>> b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>> index efbc41a..a73f3aa 100644
>>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>> @@ -19,6 +19,8 @@
>>>   #include <drm/drm_crtc_helper.h>
>>>   #include <drm/drm_plane_helper.h>
>>>
>>> +#include <linux/devfreq.h>
>>> +#include <linux/devfreq-event.h>
>>>   #include <linux/kernel.h>
>>>   #include <linux/module.h>
>>>   #include <linux/platform_device.h>
>>> @@ -118,6 +120,13 @@ struct vop {
>>>
>>>          const struct vop_data *data;
>>>
>>> +       struct devfreq *devfreq;
>>> +       struct devfreq_event_dev *devfreq_event_dev;
>>> +       struct notifier_block dmc_nb;
>>> +       int dmc_in_process;
>>> +       int vop_switch_status;
>>> +       wait_queue_head_t wait_dmc_queue;
>>> +       wait_queue_head_t wait_vop_switch_queue;
>>>          uint32_t *regsbak;
>>>          void __iomem *regs;
>>>
>>> @@ -428,11 +437,47 @@ static void vop_dsp_hold_valid_irq_disable(struct
>>> vop *vop)
>>>          spin_unlock_irqrestore(&vop->irq_lock, flags);
>>>   }
>>>
>>> +static int dmc_notify(struct notifier_block *nb, unsigned long event,
>>> +                     void *data)
>>> +{
>>> +       struct vop *vop = container_of(nb, struct vop, dmc_nb);
>>> +
>>> +       if (event == DEVFREQ_PRECHANGE) {
>>> +               /*
>>> +                * check if vop in enable or disable process,
>>> +                * if yes, wait until it finishes, use 200ms as
>>> +                * timeout.
>>> +                */
>>> +               if (!wait_event_timeout(vop->wait_vop_switch_queue,
>>> +                                       !vop->vop_switch_status, HZ / 5))
>>> +                       dev_warn(vop->dev,
>>> +                                "Timeout waiting for vop swtich
>>> status\n");
>>> +               vop->dmc_in_process = 1;
>>> +       } else if (event == DEVFREQ_POSTCHANGE) {
>>> +               vop->dmc_in_process = 0;
>>> +               wake_up(&vop->wait_dmc_queue);
>>> +       }
>>> +
>>> +       return NOTIFY_OK;
>>> +}
>>> +
>>>   static int vop_enable(struct drm_crtc *crtc)
>>>   {
>>>          struct vop *vop = to_vop(crtc);
>>> +       int num_enabled_crtc = 0;
>>>          int ret;
>>>
>>> +       /*
>>> +        * if in dmc scaling frequency process, wait until it finishes
>>> +        * use 200ms as timeout time.
>>> +        */
>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>> +                               !vop->dmc_in_process, HZ / 5))
>>> +               dev_warn(vop->dev,
>>> +                        "Timeout waiting for dmc when vop enable\n");
>>> +
>>
>>
>> This wait_event_timeout code is terribly racey (same goes above and
>> below).
>
>   No i use the vop_switch_status and dmc_in_progress to handle the vop and
> dmc racey,


So what happens if dmc_in_progress becomes 1 right here, or anywhere
during vop_enable()?

Sean




>    I assume this can fix the racey now. I do not better a idea now.
>>
>>
>>
>>> +       vop->vop_switch_status = 1;
>>> +
>>>          ret = pm_runtime_get_sync(vop->dev);
>>>          if (ret < 0) {
>>>                  dev_err(vop->dev, "failed to get pm runtime: %d\n",
>>> ret);
>>> @@ -479,6 +524,21 @@ static int vop_enable(struct drm_crtc *crtc)
>>>
>>>          drm_crtc_vblank_on(crtc);
>>>
>>> +       vop->vop_switch_status = 0;
>>> +       wake_up(&vop->wait_vop_switch_queue);
>>> +
>>> +       /* check how many VOPs in use now */
>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>> +               if (crtc->state->enable)
>>
>> I think you really want to check active, instead of enable.
>
> Okay, i will check it, thanks.
>
>>
>>> +                       num_enabled_crtc++;
>>> +       }
>>> +
>>> +       /* if enable two vop, need to disable dmc */
>>> +       if ((num_enabled_crtc > 1) && vop->devfreq) {
>>> +               if (vop->devfreq_event_dev)
>>> +
>>> devfreq_event_disable_edev(vop->devfreq_event_dev);
>>> +               devfreq_suspend_device(vop->devfreq);
>>> +       }
>>
>> This really feels like something that should be handled somewhere
>> else. I don't fully understand how this works, but it seems like this
>> dependency should be handled where it actually matters, rather than
>> building in a seemingly arbitrary restriction in the vop driver.
>>
>> Even if this is the best place for it, this needs to be refactored to
>> eliminate the races that exist now.
>>
>> Sean
>>
>>>          return 0;
>>>
>>>   err_disable_aclk:
>>> @@ -489,17 +549,31 @@ err_disable_hclk:
>>>          clk_disable(vop->hclk);
>>>   err_put_pm_runtime:
>>>          pm_runtime_put_sync(vop->dev);
>>> +       vop->vop_switch_status = 0;
>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>          return ret;
>>>   }
>>>
>>>   static void vop_crtc_disable(struct drm_crtc *crtc)
>>>   {
>>>          struct vop *vop = to_vop(crtc);
>>> +       int num_enabled_crtc = 0;
>>>          int i;
>>>
>>>          WARN_ON(vop->event);
>>>
>>>          /*
>>> +        * if in dmc scaling frequency process, wait until it finish
>>> +        * use 200ms as timeout time.
>>> +        */
>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>> +                               !vop->dmc_in_process, HZ / 5))
>>> +               dev_warn(vop->dev,
>>> +                        "Timeout waiting for dmc when vop disable\n");
>>> +
>>> +       vop->vop_switch_status = 1;
>>> +
>>> +       /*
>>>           * We need to make sure that all windows are disabled before we
>>>           * disable that crtc. Otherwise we might try to scan from a
>>> destroyed
>>>           * buffer later.
>>> @@ -555,6 +629,24 @@ static void vop_crtc_disable(struct drm_crtc *crtc)
>>>                  spin_unlock_irq(&crtc->dev->event_lock);
>>>
>>>                  crtc->state->event = NULL;
>>> +
>>> +       vop->vop_switch_status = 0;
>>> +       wake_up(&vop->wait_vop_switch_queue);
>>> +
>>> +       /* check how many VOPs in use now */
>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>> +               if (crtc->state->enable)
>>> +                       num_enabled_crtc++;
>>> +       }
>>> +
>>> +       /*
>>> +        * if num_enabled_crtc = 1 now, it means 2 vop enabled
>>> +        * change to 1 vop enabled  need to enable dmc again.
>>> +        */
>>> +       if ((num_enabled_crtc == 1) && vop->devfreq) {
>>> +               if (vop->devfreq_event_dev)
>>> +
>>> devfreq_event_enable_edev(vop->devfreq_event_dev);
>>> +               devfreq_resume_device(vop->devfreq);
>>>          }
>>>   }
>>>
>>> @@ -1413,6 +1505,8 @@ static int vop_bind(struct device *dev, struct
>>> device *master, void *data)
>>>          struct drm_device *drm_dev = data;
>>>          struct vop *vop;
>>>          struct resource *res;
>>> +       struct devfreq *devfreq;
>>> +       struct devfreq_event_dev *event_dev;
>>>          size_t alloc_size;
>>>          int ret, irq;
>>>
>>> @@ -1474,6 +1568,28 @@ static int vop_bind(struct device *dev, struct
>>> device *master, void *data)
>>>                  return ret;
>>>
>>>          pm_runtime_enable(&pdev->dev);
>>> +
>>> +       init_waitqueue_head(&vop->wait_vop_switch_queue);
>>> +       vop->vop_switch_status = 0;
>>> +       init_waitqueue_head(&vop->wait_dmc_queue);
>>> +       vop->dmc_in_process = 0;
>>> +
>>> +       devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
>>> +       if (IS_ERR(devfreq))
>>> +               goto out;
>>> +
>>> +       vop->devfreq = devfreq;
>>> +       vop->dmc_nb.notifier_call = dmc_notify;
>>> +       devfreq_register_notifier(vop->devfreq, &vop->dmc_nb,
>>> +                                 DEVFREQ_TRANSITION_NOTIFIER);
>>> +
>>> +       event_dev =
>>> devfreq_event_get_edev_by_phandle(vop->devfreq->dev.parent,
>>> +                                                     0);
>>> +       if (IS_ERR(event_dev))
>>> +               goto out;
>>> +
>>> +       vop->devfreq_event_dev = event_dev;
>>> +out:
>>>          return 0;
>>>   }
>>>
>>> --
>>> 2.6.6
>>>
>>
>>
>
> --
> Lin Huang
>
>

Re: [PATCH v10 5/5] drm/rockchip: Add dmc notifier in vop driver

[hl]

Hi

On 2016年09月07日 02:55, Sean Paul wrote:
> On Tue, Sep 6, 2016 at 2:15 PM, hl <hl@rock-chips.com> wrote:
>> Hi Sean,
>>
>>
>> On 2016年09月07日 01:18, Sean Paul wrote:
>>> On Mon, Sep 5, 2016 at 1:06 AM, Lin Huang <hl@rock-chips.com> wrote:
>>>> when in ddr frequency scaling process, vop can not do enable or
>>>> disable operation, since in dcf we check vop clock to see whether
>>>> vop work. If vop work, dcf do ddr frequency scaling when vop
>>>> in vblank status, and we need to read vop register to check whether
>>>> vop go into vblank status. If vop not work, dcf can do ddr frequency
>>>> any time. So when do ddr frequency scaling, you disabled or enable
>>>> vop, there may two bad thing happen: 1, the panel flicker(when vop from
>>>> disable status change to enable). 2, kernel hang (when vop from enable
>>>> status change to disable, dcf need to read vblank status, but if you
>>>> disable
>>>> vop clock, it can not get the status, it will lead soc dead) So we need
>>>> register to devfreq notifier, and we can get the dmc status. Also, when
>>>> there have two vop enabled, we need to disable dmc, since dcf only base
>>>> on one vop vblank time, so the other panel will flicker when do ddr
>>>> frequency scaling.
>>>>
>>>> Signed-off-by: Lin Huang <hl@rock-chips.com>
>>>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
>>>> ---
>>>> Changes in v10:
>>>> - None
>>>>
>>>> Changes in v9:
>>>> - None
>>>>
>>>> Changes in v8:
>>>> - None
>>>>
>>>> Changes in v7:
>>>> - None
>>>>
>>>> Changes in v6:
>>>> - fix a build error
>>>>
>>>> Changes in v5:
>>>> - improve some nits
>>>>
>>>> Changes in v4:
>>>> - register notifier to devfreq_register_notifier
>>>> - use DEVFREQ_PRECHANGE and DEVFREQ_POSTCHANGE to get dmc status
>>>> - when two vop enable, disable dmc
>>>> - when two vop back to one vop, enable dmc
>>>>
>>>> Changes in v3:
>>>> - when do vop eanble/disable, dmc will wait until it finish
>>>>
>>>> Changes in v2:
>>>> - None
>>>>
>>>> Changes in v1:
>>>> - use wait_event instead usleep
>>>>
>>>>    drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 116
>>>> ++++++++++++++++++++++++++++
>>>>    1 file changed, 116 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>> b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>> index efbc41a..a73f3aa 100644
>>>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>> @@ -19,6 +19,8 @@
>>>>    #include <drm/drm_crtc_helper.h>
>>>>    #include <drm/drm_plane_helper.h>
>>>>
>>>> +#include <linux/devfreq.h>
>>>> +#include <linux/devfreq-event.h>
>>>>    #include <linux/kernel.h>
>>>>    #include <linux/module.h>
>>>>    #include <linux/platform_device.h>
>>>> @@ -118,6 +120,13 @@ struct vop {
>>>>
>>>>           const struct vop_data *data;
>>>>
>>>> +       struct devfreq *devfreq;
>>>> +       struct devfreq_event_dev *devfreq_event_dev;
>>>> +       struct notifier_block dmc_nb;
>>>> +       int dmc_in_process;
>>>> +       int vop_switch_status;
>>>> +       wait_queue_head_t wait_dmc_queue;
>>>> +       wait_queue_head_t wait_vop_switch_queue;
>>>>           uint32_t *regsbak;
>>>>           void __iomem *regs;
>>>>
>>>> @@ -428,11 +437,47 @@ static void vop_dsp_hold_valid_irq_disable(struct
>>>> vop *vop)
>>>>           spin_unlock_irqrestore(&vop->irq_lock, flags);
>>>>    }
>>>>
>>>> +static int dmc_notify(struct notifier_block *nb, unsigned long event,
>>>> +                     void *data)
>>>> +{
>>>> +       struct vop *vop = container_of(nb, struct vop, dmc_nb);
>>>> +
>>>> +       if (event == DEVFREQ_PRECHANGE) {
>>>> +               /*
>>>> +                * check if vop in enable or disable process,
>>>> +                * if yes, wait until it finishes, use 200ms as
>>>> +                * timeout.
>>>> +                */
>>>> +               if (!wait_event_timeout(vop->wait_vop_switch_queue,
>>>> +                                       !vop->vop_switch_status, HZ / 5))
>>>> +                       dev_warn(vop->dev,
>>>> +                                "Timeout waiting for vop swtich
>>>> status\n");
>>>> +               vop->dmc_in_process = 1;
>>>> +       } else if (event == DEVFREQ_POSTCHANGE) {
>>>> +               vop->dmc_in_process = 0;
>>>> +               wake_up(&vop->wait_dmc_queue);
>>>> +       }
>>>> +
>>>> +       return NOTIFY_OK;
>>>> +}
>>>> +
>>>>    static int vop_enable(struct drm_crtc *crtc)
>>>>    {
>>>>           struct vop *vop = to_vop(crtc);
>>>> +       int num_enabled_crtc = 0;
>>>>           int ret;
>>>>
>>>> +       /*
>>>> +        * if in dmc scaling frequency process, wait until it finishes
>>>> +        * use 200ms as timeout time.
>>>> +        */
>>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>>> +                               !vop->dmc_in_process, HZ / 5))
>>>> +               dev_warn(vop->dev,
>>>> +                        "Timeout waiting for dmc when vop enable\n");
>>>> +
>>>
>>> This wait_event_timeout code is terribly racey (same goes above and
>>> below).
>>    No i use the vop_switch_status and dmc_in_progress to handle the vop and
>> dmc racey,
>
> So what happens if dmc_in_progress becomes 1 right here, or anywhere
> during vop_enable()?
In dmc_notify(), i will check the vop_switch_status, so in the 
vop_enable() and vop_crtc_disable(),
the dmc_in_progress can not change value.
> Sean
>
>
>
>
>>     I assume this can fix the racey now. I do not better a idea now.
>>>
>>>
>>>> +       vop->vop_switch_status = 1;
>>>> +
>>>>           ret = pm_runtime_get_sync(vop->dev);
>>>>           if (ret < 0) {
>>>>                   dev_err(vop->dev, "failed to get pm runtime: %d\n",
>>>> ret);
>>>> @@ -479,6 +524,21 @@ static int vop_enable(struct drm_crtc *crtc)
>>>>
>>>>           drm_crtc_vblank_on(crtc);
>>>>
>>>> +       vop->vop_switch_status = 0;
>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>> +
>>>> +       /* check how many VOPs in use now */
>>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>>> +               if (crtc->state->enable)
>>> I think you really want to check active, instead of enable.
>> Okay, i will check it, thanks.
>>
>>>> +                       num_enabled_crtc++;
>>>> +       }
>>>> +
>>>> +       /* if enable two vop, need to disable dmc */
>>>> +       if ((num_enabled_crtc > 1) && vop->devfreq) {
>>>> +               if (vop->devfreq_event_dev)
>>>> +
>>>> devfreq_event_disable_edev(vop->devfreq_event_dev);
>>>> +               devfreq_suspend_device(vop->devfreq);
>>>> +       }
>>> This really feels like something that should be handled somewhere
>>> else. I don't fully understand how this works, but it seems like this
>>> dependency should be handled where it actually matters, rather than
>>> building in a seemingly arbitrary restriction in the vop driver.
>>>
>>> Even if this is the best place for it, this needs to be refactored to
>>> eliminate the races that exist now.
>>>
>>> Sean
>>>
>>>>           return 0;
>>>>
>>>>    err_disable_aclk:
>>>> @@ -489,17 +549,31 @@ err_disable_hclk:
>>>>           clk_disable(vop->hclk);
>>>>    err_put_pm_runtime:
>>>>           pm_runtime_put_sync(vop->dev);
>>>> +       vop->vop_switch_status = 0;
>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>>           return ret;
>>>>    }
>>>>
>>>>    static void vop_crtc_disable(struct drm_crtc *crtc)
>>>>    {
>>>>           struct vop *vop = to_vop(crtc);
>>>> +       int num_enabled_crtc = 0;
>>>>           int i;
>>>>
>>>>           WARN_ON(vop->event);
>>>>
>>>>           /*
>>>> +        * if in dmc scaling frequency process, wait until it finish
>>>> +        * use 200ms as timeout time.
>>>> +        */
>>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>>> +                               !vop->dmc_in_process, HZ / 5))
>>>> +               dev_warn(vop->dev,
>>>> +                        "Timeout waiting for dmc when vop disable\n");
>>>> +
>>>> +       vop->vop_switch_status = 1;
>>>> +
>>>> +       /*
>>>>            * We need to make sure that all windows are disabled before we
>>>>            * disable that crtc. Otherwise we might try to scan from a
>>>> destroyed
>>>>            * buffer later.
>>>> @@ -555,6 +629,24 @@ static void vop_crtc_disable(struct drm_crtc *crtc)
>>>>                   spin_unlock_irq(&crtc->dev->event_lock);
>>>>
>>>>                   crtc->state->event = NULL;
>>>> +
>>>> +       vop->vop_switch_status = 0;
>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>> +
>>>> +       /* check how many VOPs in use now */
>>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>>> +               if (crtc->state->enable)
>>>> +                       num_enabled_crtc++;
>>>> +       }
>>>> +
>>>> +       /*
>>>> +        * if num_enabled_crtc = 1 now, it means 2 vop enabled
>>>> +        * change to 1 vop enabled  need to enable dmc again.
>>>> +        */
>>>> +       if ((num_enabled_crtc == 1) && vop->devfreq) {
>>>> +               if (vop->devfreq_event_dev)
>>>> +
>>>> devfreq_event_enable_edev(vop->devfreq_event_dev);
>>>> +               devfreq_resume_device(vop->devfreq);
>>>>           }
>>>>    }
>>>>
>>>> @@ -1413,6 +1505,8 @@ static int vop_bind(struct device *dev, struct
>>>> device *master, void *data)
>>>>           struct drm_device *drm_dev = data;
>>>>           struct vop *vop;
>>>>           struct resource *res;
>>>> +       struct devfreq *devfreq;
>>>> +       struct devfreq_event_dev *event_dev;
>>>>           size_t alloc_size;
>>>>           int ret, irq;
>>>>
>>>> @@ -1474,6 +1568,28 @@ static int vop_bind(struct device *dev, struct
>>>> device *master, void *data)
>>>>                   return ret;
>>>>
>>>>           pm_runtime_enable(&pdev->dev);
>>>> +
>>>> +       init_waitqueue_head(&vop->wait_vop_switch_queue);
>>>> +       vop->vop_switch_status = 0;
>>>> +       init_waitqueue_head(&vop->wait_dmc_queue);
>>>> +       vop->dmc_in_process = 0;
>>>> +
>>>> +       devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
>>>> +       if (IS_ERR(devfreq))
>>>> +               goto out;
>>>> +
>>>> +       vop->devfreq = devfreq;
>>>> +       vop->dmc_nb.notifier_call = dmc_notify;
>>>> +       devfreq_register_notifier(vop->devfreq, &vop->dmc_nb,
>>>> +                                 DEVFREQ_TRANSITION_NOTIFIER);
>>>> +
>>>> +       event_dev =
>>>> devfreq_event_get_edev_by_phandle(vop->devfreq->dev.parent,
>>>> +                                                     0);
>>>> +       if (IS_ERR(event_dev))
>>>> +               goto out;
>>>> +
>>>> +       vop->devfreq_event_dev = event_dev;
>>>> +out:
>>>>           return 0;
>>>>    }
>>>>
>>>> --
>>>> 2.6.6
>>>>
>>>
>> --
>> Lin Huang
>>
>>
>
>

-- 
Lin Huang

Re: [PATCH v10 5/5] drm/rockchip: Add dmc notifier in vop driver

[Sean Paul]

On Tue, Sep 6, 2016 at 3:01 PM, hl <hl@rock-chips.com> wrote:
> Hi
>
>
> On 2016年09月07日 02:55, Sean Paul wrote:
>>
>> On Tue, Sep 6, 2016 at 2:15 PM, hl <hl@rock-chips.com> wrote:
>>>
>>> Hi Sean,
>>>
>>>
>>> On 2016年09月07日 01:18, Sean Paul wrote:
>>>>
>>>> On Mon, Sep 5, 2016 at 1:06 AM, Lin Huang <hl@rock-chips.com> wrote:
>>>>>
>>>>> when in ddr frequency scaling process, vop can not do enable or
>>>>> disable operation, since in dcf we check vop clock to see whether
>>>>> vop work. If vop work, dcf do ddr frequency scaling when vop
>>>>> in vblank status, and we need to read vop register to check whether
>>>>> vop go into vblank status. If vop not work, dcf can do ddr frequency
>>>>> any time. So when do ddr frequency scaling, you disabled or enable
>>>>> vop, there may two bad thing happen: 1, the panel flicker(when vop from
>>>>> disable status change to enable). 2, kernel hang (when vop from enable
>>>>> status change to disable, dcf need to read vblank status, but if you
>>>>> disable
>>>>> vop clock, it can not get the status, it will lead soc dead) So we need
>>>>> register to devfreq notifier, and we can get the dmc status. Also, when
>>>>> there have two vop enabled, we need to disable dmc, since dcf only base
>>>>> on one vop vblank time, so the other panel will flicker when do ddr
>>>>> frequency scaling.
>>>>>
>>>>> Signed-off-by: Lin Huang <hl@rock-chips.com>
>>>>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
>>>>> ---
>>>>> Changes in v10:
>>>>> - None
>>>>>
>>>>> Changes in v9:
>>>>> - None
>>>>>
>>>>> Changes in v8:
>>>>> - None
>>>>>
>>>>> Changes in v7:
>>>>> - None
>>>>>
>>>>> Changes in v6:
>>>>> - fix a build error
>>>>>
>>>>> Changes in v5:
>>>>> - improve some nits
>>>>>
>>>>> Changes in v4:
>>>>> - register notifier to devfreq_register_notifier
>>>>> - use DEVFREQ_PRECHANGE and DEVFREQ_POSTCHANGE to get dmc status
>>>>> - when two vop enable, disable dmc
>>>>> - when two vop back to one vop, enable dmc
>>>>>
>>>>> Changes in v3:
>>>>> - when do vop eanble/disable, dmc will wait until it finish
>>>>>
>>>>> Changes in v2:
>>>>> - None
>>>>>
>>>>> Changes in v1:
>>>>> - use wait_event instead usleep
>>>>>
>>>>>    drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 116
>>>>> ++++++++++++++++++++++++++++
>>>>>    1 file changed, 116 insertions(+)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>>> b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>>> index efbc41a..a73f3aa 100644
>>>>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>>> @@ -19,6 +19,8 @@
>>>>>    #include <drm/drm_crtc_helper.h>
>>>>>    #include <drm/drm_plane_helper.h>
>>>>>
>>>>> +#include <linux/devfreq.h>
>>>>> +#include <linux/devfreq-event.h>
>>>>>    #include <linux/kernel.h>
>>>>>    #include <linux/module.h>
>>>>>    #include <linux/platform_device.h>
>>>>> @@ -118,6 +120,13 @@ struct vop {
>>>>>
>>>>>           const struct vop_data *data;
>>>>>
>>>>> +       struct devfreq *devfreq;
>>>>> +       struct devfreq_event_dev *devfreq_event_dev;
>>>>> +       struct notifier_block dmc_nb;
>>>>> +       int dmc_in_process;
>>>>> +       int vop_switch_status;
>>>>> +       wait_queue_head_t wait_dmc_queue;
>>>>> +       wait_queue_head_t wait_vop_switch_queue;
>>>>>           uint32_t *regsbak;
>>>>>           void __iomem *regs;
>>>>>
>>>>> @@ -428,11 +437,47 @@ static void vop_dsp_hold_valid_irq_disable(struct
>>>>> vop *vop)
>>>>>           spin_unlock_irqrestore(&vop->irq_lock, flags);
>>>>>    }
>>>>>
>>>>> +static int dmc_notify(struct notifier_block *nb, unsigned long event,
>>>>> +                     void *data)
>>>>> +{
>>>>> +       struct vop *vop = container_of(nb, struct vop, dmc_nb);
>>>>> +
>>>>> +       if (event == DEVFREQ_PRECHANGE) {
>>>>> +               /*
>>>>> +                * check if vop in enable or disable process,
>>>>> +                * if yes, wait until it finishes, use 200ms as
>>>>> +                * timeout.
>>>>> +                */
>>>>> +               if (!wait_event_timeout(vop->wait_vop_switch_queue,
>>>>> +                                       !vop->vop_switch_status, HZ /
>>>>> 5))
>>>>> +                       dev_warn(vop->dev,
>>>>> +                                "Timeout waiting for vop swtich
>>>>> status\n");
>>>>> +               vop->dmc_in_process = 1;
>>>>> +       } else if (event == DEVFREQ_POSTCHANGE) {
>>>>> +               vop->dmc_in_process = 0;
>>>>> +               wake_up(&vop->wait_dmc_queue);
>>>>> +       }
>>>>> +
>>>>> +       return NOTIFY_OK;
>>>>> +}
>>>>> +
>>>>>    static int vop_enable(struct drm_crtc *crtc)
>>>>>    {
>>>>>           struct vop *vop = to_vop(crtc);
>>>>> +       int num_enabled_crtc = 0;
>>>>>           int ret;
>>>>>
>>>>> +       /*
>>>>> +        * if in dmc scaling frequency process, wait until it finishes
>>>>> +        * use 200ms as timeout time.
>>>>> +        */
>>>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>>>> +                               !vop->dmc_in_process, HZ / 5))
>>>>> +               dev_warn(vop->dev,
>>>>> +                        "Timeout waiting for dmc when vop enable\n");
>>>>> +
>>>>
>>>>
>>>> This wait_event_timeout code is terribly racey (same goes above and
>>>> below).
>>>
>>>    No i use the vop_switch_status and dmc_in_progress to handle the vop
>>> and
>>> dmc racey,
>>
>>
>> So what happens if dmc_in_progress becomes 1 right here, or anywhere
>> during vop_enable()?
>
> In dmc_notify(), i will check the vop_switch_status, so in the vop_enable()
> and vop_crtc_disable(),
> the dmc_in_progress can not change value.
>


THREAD 1 - wait_event_timeout (vop_switch_status)
THREAD 2 - wait_event_timeout(wait_dmc_queue)
THREAD 2 - vop_switch_status = 1
THREAD 1 - dmc_in_progress = 1

Sean


>> Sean
>>
>>
>>
>>
>>>     I assume this can fix the racey now. I do not better a idea now.
>>>>
>>>>
>>>>
>>>>> +       vop->vop_switch_status = 1;
>>>>> +
>>>>>           ret = pm_runtime_get_sync(vop->dev);
>>>>>           if (ret < 0) {
>>>>>                   dev_err(vop->dev, "failed to get pm runtime: %d\n",
>>>>> ret);
>>>>> @@ -479,6 +524,21 @@ static int vop_enable(struct drm_crtc *crtc)
>>>>>
>>>>>           drm_crtc_vblank_on(crtc);
>>>>>
>>>>> +       vop->vop_switch_status = 0;
>>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>>> +
>>>>> +       /* check how many VOPs in use now */
>>>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>>>> +               if (crtc->state->enable)
>>>>
>>>> I think you really want to check active, instead of enable.
>>>
>>> Okay, i will check it, thanks.
>>>
>>>>> +                       num_enabled_crtc++;
>>>>> +       }
>>>>> +
>>>>> +       /* if enable two vop, need to disable dmc */
>>>>> +       if ((num_enabled_crtc > 1) && vop->devfreq) {
>>>>> +               if (vop->devfreq_event_dev)
>>>>> +
>>>>> devfreq_event_disable_edev(vop->devfreq_event_dev);
>>>>> +               devfreq_suspend_device(vop->devfreq);
>>>>> +       }
>>>>
>>>> This really feels like something that should be handled somewhere
>>>> else. I don't fully understand how this works, but it seems like this
>>>> dependency should be handled where it actually matters, rather than
>>>> building in a seemingly arbitrary restriction in the vop driver.
>>>>
>>>> Even if this is the best place for it, this needs to be refactored to
>>>> eliminate the races that exist now.
>>>>
>>>> Sean
>>>>
>>>>>           return 0;
>>>>>
>>>>>    err_disable_aclk:
>>>>> @@ -489,17 +549,31 @@ err_disable_hclk:
>>>>>           clk_disable(vop->hclk);
>>>>>    err_put_pm_runtime:
>>>>>           pm_runtime_put_sync(vop->dev);
>>>>> +       vop->vop_switch_status = 0;
>>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>>>           return ret;
>>>>>    }
>>>>>
>>>>>    static void vop_crtc_disable(struct drm_crtc *crtc)
>>>>>    {
>>>>>           struct vop *vop = to_vop(crtc);
>>>>> +       int num_enabled_crtc = 0;
>>>>>           int i;
>>>>>
>>>>>           WARN_ON(vop->event);
>>>>>
>>>>>           /*
>>>>> +        * if in dmc scaling frequency process, wait until it finish
>>>>> +        * use 200ms as timeout time.
>>>>> +        */
>>>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>>>> +                               !vop->dmc_in_process, HZ / 5))
>>>>> +               dev_warn(vop->dev,
>>>>> +                        "Timeout waiting for dmc when vop disable\n");
>>>>> +
>>>>> +       vop->vop_switch_status = 1;
>>>>> +
>>>>> +       /*
>>>>>            * We need to make sure that all windows are disabled before
>>>>> we
>>>>>            * disable that crtc. Otherwise we might try to scan from a
>>>>> destroyed
>>>>>            * buffer later.
>>>>> @@ -555,6 +629,24 @@ static void vop_crtc_disable(struct drm_crtc
>>>>> *crtc)
>>>>>                   spin_unlock_irq(&crtc->dev->event_lock);
>>>>>
>>>>>                   crtc->state->event = NULL;
>>>>> +
>>>>> +       vop->vop_switch_status = 0;
>>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>>> +
>>>>> +       /* check how many VOPs in use now */
>>>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>>>> +               if (crtc->state->enable)
>>>>> +                       num_enabled_crtc++;
>>>>> +       }
>>>>> +
>>>>> +       /*
>>>>> +        * if num_enabled_crtc = 1 now, it means 2 vop enabled
>>>>> +        * change to 1 vop enabled  need to enable dmc again.
>>>>> +        */
>>>>> +       if ((num_enabled_crtc == 1) && vop->devfreq) {
>>>>> +               if (vop->devfreq_event_dev)
>>>>> +
>>>>> devfreq_event_enable_edev(vop->devfreq_event_dev);
>>>>> +               devfreq_resume_device(vop->devfreq);
>>>>>           }
>>>>>    }
>>>>>
>>>>> @@ -1413,6 +1505,8 @@ static int vop_bind(struct device *dev, struct
>>>>> device *master, void *data)
>>>>>           struct drm_device *drm_dev = data;
>>>>>           struct vop *vop;
>>>>>           struct resource *res;
>>>>> +       struct devfreq *devfreq;
>>>>> +       struct devfreq_event_dev *event_dev;
>>>>>           size_t alloc_size;
>>>>>           int ret, irq;
>>>>>
>>>>> @@ -1474,6 +1568,28 @@ static int vop_bind(struct device *dev, struct
>>>>> device *master, void *data)
>>>>>                   return ret;
>>>>>
>>>>>           pm_runtime_enable(&pdev->dev);
>>>>> +
>>>>> +       init_waitqueue_head(&vop->wait_vop_switch_queue);
>>>>> +       vop->vop_switch_status = 0;
>>>>> +       init_waitqueue_head(&vop->wait_dmc_queue);
>>>>> +       vop->dmc_in_process = 0;
>>>>> +
>>>>> +       devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
>>>>> +       if (IS_ERR(devfreq))
>>>>> +               goto out;
>>>>> +
>>>>> +       vop->devfreq = devfreq;
>>>>> +       vop->dmc_nb.notifier_call = dmc_notify;
>>>>> +       devfreq_register_notifier(vop->devfreq, &vop->dmc_nb,
>>>>> +                                 DEVFREQ_TRANSITION_NOTIFIER);
>>>>> +
>>>>> +       event_dev =
>>>>> devfreq_event_get_edev_by_phandle(vop->devfreq->dev.parent,
>>>>> +                                                     0);
>>>>> +       if (IS_ERR(event_dev))
>>>>> +               goto out;
>>>>> +
>>>>> +       vop->devfreq_event_dev = event_dev;
>>>>> +out:
>>>>>           return 0;
>>>>>    }
>>>>>
>>>>> --
>>>>> 2.6.6
>>>>>
>>>>
>>> --
>>> Lin Huang
>>>
>>>
>>
>>
>
> --
> Lin Huang
>
>

Re: [PATCH v10 5/5] drm/rockchip: Add dmc notifier in vop driver

[dbasehore .]

On Tue, Sep 6, 2016 at 12:07 PM, Sean Paul <seanpaul@google.com> wrote:
> On Tue, Sep 6, 2016 at 3:01 PM, hl <hl@rock-chips.com> wrote:
>> Hi
>>
>>
>> On 2016年09月07日 02:55, Sean Paul wrote:
>>>
>>> On Tue, Sep 6, 2016 at 2:15 PM, hl <hl@rock-chips.com> wrote:
>>>>
>>>> Hi Sean,
>>>>
>>>>
>>>> On 2016年09月07日 01:18, Sean Paul wrote:
>>>>>
>>>>> On Mon, Sep 5, 2016 at 1:06 AM, Lin Huang <hl@rock-chips.com> wrote:
>>>>>>
>>>>>> when in ddr frequency scaling process, vop can not do enable or
>>>>>> disable operation, since in dcf we check vop clock to see whether
>>>>>> vop work. If vop work, dcf do ddr frequency scaling when vop
>>>>>> in vblank status, and we need to read vop register to check whether
>>>>>> vop go into vblank status. If vop not work, dcf can do ddr frequency
>>>>>> any time. So when do ddr frequency scaling, you disabled or enable
>>>>>> vop, there may two bad thing happen: 1, the panel flicker(when vop from
>>>>>> disable status change to enable). 2, kernel hang (when vop from enable
>>>>>> status change to disable, dcf need to read vblank status, but if you
>>>>>> disable
>>>>>> vop clock, it can not get the status, it will lead soc dead) So we need
>>>>>> register to devfreq notifier, and we can get the dmc status. Also, when
>>>>>> there have two vop enabled, we need to disable dmc, since dcf only base
>>>>>> on one vop vblank time, so the other panel will flicker when do ddr
>>>>>> frequency scaling.
>>>>>>
>>>>>> Signed-off-by: Lin Huang <hl@rock-chips.com>
>>>>>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
>>>>>> ---
>>>>>> Changes in v10:
>>>>>> - None
>>>>>>
>>>>>> Changes in v9:
>>>>>> - None
>>>>>>
>>>>>> Changes in v8:
>>>>>> - None
>>>>>>
>>>>>> Changes in v7:
>>>>>> - None
>>>>>>
>>>>>> Changes in v6:
>>>>>> - fix a build error
>>>>>>
>>>>>> Changes in v5:
>>>>>> - improve some nits
>>>>>>
>>>>>> Changes in v4:
>>>>>> - register notifier to devfreq_register_notifier
>>>>>> - use DEVFREQ_PRECHANGE and DEVFREQ_POSTCHANGE to get dmc status
>>>>>> - when two vop enable, disable dmc
>>>>>> - when two vop back to one vop, enable dmc
>>>>>>
>>>>>> Changes in v3:
>>>>>> - when do vop eanble/disable, dmc will wait until it finish
>>>>>>
>>>>>> Changes in v2:
>>>>>> - None
>>>>>>
>>>>>> Changes in v1:
>>>>>> - use wait_event instead usleep
>>>>>>
>>>>>>    drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 116
>>>>>> ++++++++++++++++++++++++++++
>>>>>>    1 file changed, 116 insertions(+)
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>>>> b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>>>> index efbc41a..a73f3aa 100644
>>>>>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>>>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>>>> @@ -19,6 +19,8 @@
>>>>>>    #include <drm/drm_crtc_helper.h>
>>>>>>    #include <drm/drm_plane_helper.h>
>>>>>>
>>>>>> +#include <linux/devfreq.h>
>>>>>> +#include <linux/devfreq-event.h>
>>>>>>    #include <linux/kernel.h>
>>>>>>    #include <linux/module.h>
>>>>>>    #include <linux/platform_device.h>
>>>>>> @@ -118,6 +120,13 @@ struct vop {
>>>>>>
>>>>>>           const struct vop_data *data;
>>>>>>
>>>>>> +       struct devfreq *devfreq;
>>>>>> +       struct devfreq_event_dev *devfreq_event_dev;
>>>>>> +       struct notifier_block dmc_nb;
>>>>>> +       int dmc_in_process;
>>>>>> +       int vop_switch_status;
>>>>>> +       wait_queue_head_t wait_dmc_queue;
>>>>>> +       wait_queue_head_t wait_vop_switch_queue;
>>>>>>           uint32_t *regsbak;
>>>>>>           void __iomem *regs;
>>>>>>
>>>>>> @@ -428,11 +437,47 @@ static void vop_dsp_hold_valid_irq_disable(struct
>>>>>> vop *vop)
>>>>>>           spin_unlock_irqrestore(&vop->irq_lock, flags);
>>>>>>    }
>>>>>>
>>>>>> +static int dmc_notify(struct notifier_block *nb, unsigned long event,
>>>>>> +                     void *data)
>>>>>> +{
>>>>>> +       struct vop *vop = container_of(nb, struct vop, dmc_nb);
>>>>>> +
>>>>>> +       if (event == DEVFREQ_PRECHANGE) {
>>>>>> +               /*
>>>>>> +                * check if vop in enable or disable process,
>>>>>> +                * if yes, wait until it finishes, use 200ms as
>>>>>> +                * timeout.
>>>>>> +                */
>>>>>> +               if (!wait_event_timeout(vop->wait_vop_switch_queue,
>>>>>> +                                       !vop->vop_switch_status, HZ /
>>>>>> 5))
>>>>>> +                       dev_warn(vop->dev,
>>>>>> +                                "Timeout waiting for vop swtich
>>>>>> status\n");
>>>>>> +               vop->dmc_in_process = 1;
>>>>>> +       } else if (event == DEVFREQ_POSTCHANGE) {
>>>>>> +               vop->dmc_in_process = 0;
>>>>>> +               wake_up(&vop->wait_dmc_queue);
>>>>>> +       }
>>>>>> +
>>>>>> +       return NOTIFY_OK;
>>>>>> +}
>>>>>> +
>>>>>>    static int vop_enable(struct drm_crtc *crtc)
>>>>>>    {
>>>>>>           struct vop *vop = to_vop(crtc);
>>>>>> +       int num_enabled_crtc = 0;
>>>>>>           int ret;
>>>>>>
>>>>>> +       /*
>>>>>> +        * if in dmc scaling frequency process, wait until it finishes
>>>>>> +        * use 200ms as timeout time.
>>>>>> +        */
>>>>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>>>>> +                               !vop->dmc_in_process, HZ / 5))
>>>>>> +               dev_warn(vop->dev,
>>>>>> +                        "Timeout waiting for dmc when vop enable\n");
>>>>>> +
>>>>>
>>>>>
>>>>> This wait_event_timeout code is terribly racey (same goes above and
>>>>> below).
>>>>
>>>>    No i use the vop_switch_status and dmc_in_progress to handle the vop
>>>> and
>>>> dmc racey,
>>>
>>>
>>> So what happens if dmc_in_progress becomes 1 right here, or anywhere
>>> during vop_enable()?
>>
>> In dmc_notify(), i will check the vop_switch_status, so in the vop_enable()
>> and vop_crtc_disable(),
>> the dmc_in_progress can not change value.
>>
>
>
> THREAD 1 - wait_event_timeout (vop_switch_status)
> THREAD 2 - wait_event_timeout(wait_dmc_queue)
> THREAD 2 - vop_switch_status = 1
> THREAD 1 - dmc_in_progress = 1
>
> Sean
>

I've thought about how to handle these timeout conditions, and it
might be best to get rid of them. These would actually be error
conditions, and we don't plan to hit them.

Also, if something goes wrong with DMC frequency transitions, we are
likely out of luck and going to panic anyways.

>
>>> Sean
>>>
>>>
>>>
>>>
>>>>     I assume this can fix the racey now. I do not better a idea now.
>>>>>
>>>>>
>>>>>
>>>>>> +       vop->vop_switch_status = 1;
>>>>>> +
>>>>>>           ret = pm_runtime_get_sync(vop->dev);
>>>>>>           if (ret < 0) {
>>>>>>                   dev_err(vop->dev, "failed to get pm runtime: %d\n",
>>>>>> ret);
>>>>>> @@ -479,6 +524,21 @@ static int vop_enable(struct drm_crtc *crtc)
>>>>>>
>>>>>>           drm_crtc_vblank_on(crtc);
>>>>>>
>>>>>> +       vop->vop_switch_status = 0;
>>>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>>>> +
>>>>>> +       /* check how many VOPs in use now */
>>>>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>>>>> +               if (crtc->state->enable)
>>>>>
>>>>> I think you really want to check active, instead of enable.
>>>>
>>>> Okay, i will check it, thanks.
>>>>
>>>>>> +                       num_enabled_crtc++;
>>>>>> +       }
>>>>>> +
>>>>>> +       /* if enable two vop, need to disable dmc */
>>>>>> +       if ((num_enabled_crtc > 1) && vop->devfreq) {
>>>>>> +               if (vop->devfreq_event_dev)
>>>>>> +
>>>>>> devfreq_event_disable_edev(vop->devfreq_event_dev);
>>>>>> +               devfreq_suspend_device(vop->devfreq);
>>>>>> +       }
>>>>>
>>>>> This really feels like something that should be handled somewhere
>>>>> else. I don't fully understand how this works, but it seems like this
>>>>> dependency should be handled where it actually matters, rather than
>>>>> building in a seemingly arbitrary restriction in the vop driver.
>>>>>
>>>>> Even if this is the best place for it, this needs to be refactored to
>>>>> eliminate the races that exist now.
>>>>>
>>>>> Sean
>>>>>
>>>>>>           return 0;
>>>>>>
>>>>>>    err_disable_aclk:
>>>>>> @@ -489,17 +549,31 @@ err_disable_hclk:
>>>>>>           clk_disable(vop->hclk);
>>>>>>    err_put_pm_runtime:
>>>>>>           pm_runtime_put_sync(vop->dev);
>>>>>> +       vop->vop_switch_status = 0;
>>>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>>>>           return ret;
>>>>>>    }
>>>>>>
>>>>>>    static void vop_crtc_disable(struct drm_crtc *crtc)
>>>>>>    {
>>>>>>           struct vop *vop = to_vop(crtc);
>>>>>> +       int num_enabled_crtc = 0;
>>>>>>           int i;
>>>>>>
>>>>>>           WARN_ON(vop->event);
>>>>>>
>>>>>>           /*
>>>>>> +        * if in dmc scaling frequency process, wait until it finish
>>>>>> +        * use 200ms as timeout time.
>>>>>> +        */
>>>>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>>>>> +                               !vop->dmc_in_process, HZ / 5))
>>>>>> +               dev_warn(vop->dev,
>>>>>> +                        "Timeout waiting for dmc when vop disable\n");
>>>>>> +
>>>>>> +       vop->vop_switch_status = 1;
>>>>>> +
>>>>>> +       /*
>>>>>>            * We need to make sure that all windows are disabled before
>>>>>> we
>>>>>>            * disable that crtc. Otherwise we might try to scan from a
>>>>>> destroyed
>>>>>>            * buffer later.
>>>>>> @@ -555,6 +629,24 @@ static void vop_crtc_disable(struct drm_crtc
>>>>>> *crtc)
>>>>>>                   spin_unlock_irq(&crtc->dev->event_lock);
>>>>>>
>>>>>>                   crtc->state->event = NULL;
>>>>>> +
>>>>>> +       vop->vop_switch_status = 0;
>>>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>>>> +
>>>>>> +       /* check how many VOPs in use now */
>>>>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>>>>> +               if (crtc->state->enable)
>>>>>> +                       num_enabled_crtc++;
>>>>>> +       }
>>>>>> +
>>>>>> +       /*
>>>>>> +        * if num_enabled_crtc = 1 now, it means 2 vop enabled
>>>>>> +        * change to 1 vop enabled  need to enable dmc again.
>>>>>> +        */
>>>>>> +       if ((num_enabled_crtc == 1) && vop->devfreq) {
>>>>>> +               if (vop->devfreq_event_dev)
>>>>>> +
>>>>>> devfreq_event_enable_edev(vop->devfreq_event_dev);
>>>>>> +               devfreq_resume_device(vop->devfreq);
>>>>>>           }
>>>>>>    }
>>>>>>
>>>>>> @@ -1413,6 +1505,8 @@ static int vop_bind(struct device *dev, struct
>>>>>> device *master, void *data)
>>>>>>           struct drm_device *drm_dev = data;
>>>>>>           struct vop *vop;
>>>>>>           struct resource *res;
>>>>>> +       struct devfreq *devfreq;
>>>>>> +       struct devfreq_event_dev *event_dev;
>>>>>>           size_t alloc_size;
>>>>>>           int ret, irq;
>>>>>>
>>>>>> @@ -1474,6 +1568,28 @@ static int vop_bind(struct device *dev, struct
>>>>>> device *master, void *data)
>>>>>>                   return ret;
>>>>>>
>>>>>>           pm_runtime_enable(&pdev->dev);
>>>>>> +
>>>>>> +       init_waitqueue_head(&vop->wait_vop_switch_queue);
>>>>>> +       vop->vop_switch_status = 0;
>>>>>> +       init_waitqueue_head(&vop->wait_dmc_queue);
>>>>>> +       vop->dmc_in_process = 0;
>>>>>> +
>>>>>> +       devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
>>>>>> +       if (IS_ERR(devfreq))
>>>>>> +               goto out;
>>>>>> +
>>>>>> +       vop->devfreq = devfreq;
>>>>>> +       vop->dmc_nb.notifier_call = dmc_notify;
>>>>>> +       devfreq_register_notifier(vop->devfreq, &vop->dmc_nb,
>>>>>> +                                 DEVFREQ_TRANSITION_NOTIFIER);
>>>>>> +
>>>>>> +       event_dev =
>>>>>> devfreq_event_get_edev_by_phandle(vop->devfreq->dev.parent,
>>>>>> +                                                     0);
>>>>>> +       if (IS_ERR(event_dev))
>>>>>> +               goto out;
>>>>>> +
>>>>>> +       vop->devfreq_event_dev = event_dev;
>>>>>> +out:
>>>>>>           return 0;
>>>>>>    }
>>>>>>
>>>>>> --
>>>>>> 2.6.6
>>>>>>
>>>>>
>>>> --
>>>> Lin Huang
>>>>
>>>>
>>>
>>>
>>
>> --
>> Lin Huang
>>
>>

Re: [PATCH v10 5/5] drm/rockchip: Add dmc notifier in vop driver

[Sean Paul]

On Wed, Sep 7, 2016 at 2:07 PM, dbasehore . <dbasehore@chromium.org> wrote:
> On Tue, Sep 6, 2016 at 12:07 PM, Sean Paul <seanpaul@google.com> wrote:
>> On Tue, Sep 6, 2016 at 3:01 PM, hl <hl@rock-chips.com> wrote:
>>> Hi
>>>
>>>
>>> On 2016年09月07日 02:55, Sean Paul wrote:
>>>>
>>>> On Tue, Sep 6, 2016 at 2:15 PM, hl <hl@rock-chips.com> wrote:
>>>>>
>>>>> Hi Sean,
>>>>>
>>>>>
>>>>> On 2016年09月07日 01:18, Sean Paul wrote:
>>>>>>
>>>>>> On Mon, Sep 5, 2016 at 1:06 AM, Lin Huang <hl@rock-chips.com> wrote:
>>>>>>>
>>>>>>> when in ddr frequency scaling process, vop can not do enable or
>>>>>>> disable operation, since in dcf we check vop clock to see whether
>>>>>>> vop work. If vop work, dcf do ddr frequency scaling when vop
>>>>>>> in vblank status, and we need to read vop register to check whether
>>>>>>> vop go into vblank status. If vop not work, dcf can do ddr frequency
>>>>>>> any time. So when do ddr frequency scaling, you disabled or enable
>>>>>>> vop, there may two bad thing happen: 1, the panel flicker(when vop from
>>>>>>> disable status change to enable). 2, kernel hang (when vop from enable
>>>>>>> status change to disable, dcf need to read vblank status, but if you
>>>>>>> disable
>>>>>>> vop clock, it can not get the status, it will lead soc dead) So we need
>>>>>>> register to devfreq notifier, and we can get the dmc status. Also, when
>>>>>>> there have two vop enabled, we need to disable dmc, since dcf only base
>>>>>>> on one vop vblank time, so the other panel will flicker when do ddr
>>>>>>> frequency scaling.
>>>>>>>
>>>>>>> Signed-off-by: Lin Huang <hl@rock-chips.com>
>>>>>>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
>>>>>>> ---
>>>>>>> Changes in v10:
>>>>>>> - None
>>>>>>>
>>>>>>> Changes in v9:
>>>>>>> - None
>>>>>>>
>>>>>>> Changes in v8:
>>>>>>> - None
>>>>>>>
>>>>>>> Changes in v7:
>>>>>>> - None
>>>>>>>
>>>>>>> Changes in v6:
>>>>>>> - fix a build error
>>>>>>>
>>>>>>> Changes in v5:
>>>>>>> - improve some nits
>>>>>>>
>>>>>>> Changes in v4:
>>>>>>> - register notifier to devfreq_register_notifier
>>>>>>> - use DEVFREQ_PRECHANGE and DEVFREQ_POSTCHANGE to get dmc status
>>>>>>> - when two vop enable, disable dmc
>>>>>>> - when two vop back to one vop, enable dmc
>>>>>>>
>>>>>>> Changes in v3:
>>>>>>> - when do vop eanble/disable, dmc will wait until it finish
>>>>>>>
>>>>>>> Changes in v2:
>>>>>>> - None
>>>>>>>
>>>>>>> Changes in v1:
>>>>>>> - use wait_event instead usleep
>>>>>>>
>>>>>>>    drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 116
>>>>>>> ++++++++++++++++++++++++++++
>>>>>>>    1 file changed, 116 insertions(+)
>>>>>>>
>>>>>>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>>>>> b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>>>>> index efbc41a..a73f3aa 100644
>>>>>>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>>>>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>>>>> @@ -19,6 +19,8 @@
>>>>>>>    #include <drm/drm_crtc_helper.h>
>>>>>>>    #include <drm/drm_plane_helper.h>
>>>>>>>
>>>>>>> +#include <linux/devfreq.h>
>>>>>>> +#include <linux/devfreq-event.h>
>>>>>>>    #include <linux/kernel.h>
>>>>>>>    #include <linux/module.h>
>>>>>>>    #include <linux/platform_device.h>
>>>>>>> @@ -118,6 +120,13 @@ struct vop {
>>>>>>>
>>>>>>>           const struct vop_data *data;
>>>>>>>
>>>>>>> +       struct devfreq *devfreq;
>>>>>>> +       struct devfreq_event_dev *devfreq_event_dev;
>>>>>>> +       struct notifier_block dmc_nb;
>>>>>>> +       int dmc_in_process;
>>>>>>> +       int vop_switch_status;
>>>>>>> +       wait_queue_head_t wait_dmc_queue;
>>>>>>> +       wait_queue_head_t wait_vop_switch_queue;
>>>>>>>           uint32_t *regsbak;
>>>>>>>           void __iomem *regs;
>>>>>>>
>>>>>>> @@ -428,11 +437,47 @@ static void vop_dsp_hold_valid_irq_disable(struct
>>>>>>> vop *vop)
>>>>>>>           spin_unlock_irqrestore(&vop->irq_lock, flags);
>>>>>>>    }
>>>>>>>
>>>>>>> +static int dmc_notify(struct notifier_block *nb, unsigned long event,
>>>>>>> +                     void *data)
>>>>>>> +{
>>>>>>> +       struct vop *vop = container_of(nb, struct vop, dmc_nb);
>>>>>>> +
>>>>>>> +       if (event == DEVFREQ_PRECHANGE) {
>>>>>>> +               /*
>>>>>>> +                * check if vop in enable or disable process,
>>>>>>> +                * if yes, wait until it finishes, use 200ms as
>>>>>>> +                * timeout.
>>>>>>> +                */
>>>>>>> +               if (!wait_event_timeout(vop->wait_vop_switch_queue,
>>>>>>> +                                       !vop->vop_switch_status, HZ /
>>>>>>> 5))
>>>>>>> +                       dev_warn(vop->dev,
>>>>>>> +                                "Timeout waiting for vop swtich
>>>>>>> status\n");
>>>>>>> +               vop->dmc_in_process = 1;
>>>>>>> +       } else if (event == DEVFREQ_POSTCHANGE) {
>>>>>>> +               vop->dmc_in_process = 0;
>>>>>>> +               wake_up(&vop->wait_dmc_queue);
>>>>>>> +       }
>>>>>>> +
>>>>>>> +       return NOTIFY_OK;
>>>>>>> +}
>>>>>>> +
>>>>>>>    static int vop_enable(struct drm_crtc *crtc)
>>>>>>>    {
>>>>>>>           struct vop *vop = to_vop(crtc);
>>>>>>> +       int num_enabled_crtc = 0;
>>>>>>>           int ret;
>>>>>>>
>>>>>>> +       /*
>>>>>>> +        * if in dmc scaling frequency process, wait until it finishes
>>>>>>> +        * use 200ms as timeout time.
>>>>>>> +        */
>>>>>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>>>>>> +                               !vop->dmc_in_process, HZ / 5))
>>>>>>> +               dev_warn(vop->dev,
>>>>>>> +                        "Timeout waiting for dmc when vop enable\n");
>>>>>>> +
>>>>>>
>>>>>>
>>>>>> This wait_event_timeout code is terribly racey (same goes above and
>>>>>> below).
>>>>>
>>>>>    No i use the vop_switch_status and dmc_in_progress to handle the vop
>>>>> and
>>>>> dmc racey,
>>>>
>>>>
>>>> So what happens if dmc_in_progress becomes 1 right here, or anywhere
>>>> during vop_enable()?
>>>
>>> In dmc_notify(), i will check the vop_switch_status, so in the vop_enable()
>>> and vop_crtc_disable(),
>>> the dmc_in_progress can not change value.
>>>
>>
>>
>> THREAD 1 - wait_event_timeout (vop_switch_status)
>> THREAD 2 - wait_event_timeout(wait_dmc_queue)
>> THREAD 2 - vop_switch_status = 1
>> THREAD 1 - dmc_in_progress = 1
>>
>> Sean
>>
>
> I've thought about how to handle these timeout conditions, and it
> might be best to get rid of them. These would actually be error
> conditions, and we don't plan to hit them.
>
> Also, if something goes wrong with DMC frequency transitions, we are
> likely out of luck and going to panic anyways.

Yeah, I'm not sure if the timeouts are recoverable (makes sense that
they're not), but this code has several different variations of the
race I described above.

I'm working on something a little more buttoned down to hopefully sync
things up better.

Sean


>
>>
>>>> Sean
>>>>
>>>>
>>>>
>>>>
>>>>>     I assume this can fix the racey now. I do not better a idea now.
>>>>>>
>>>>>>
>>>>>>
>>>>>>> +       vop->vop_switch_status = 1;
>>>>>>> +
>>>>>>>           ret = pm_runtime_get_sync(vop->dev);
>>>>>>>           if (ret < 0) {
>>>>>>>                   dev_err(vop->dev, "failed to get pm runtime: %d\n",
>>>>>>> ret);
>>>>>>> @@ -479,6 +524,21 @@ static int vop_enable(struct drm_crtc *crtc)
>>>>>>>
>>>>>>>           drm_crtc_vblank_on(crtc);
>>>>>>>
>>>>>>> +       vop->vop_switch_status = 0;
>>>>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>>>>> +
>>>>>>> +       /* check how many VOPs in use now */
>>>>>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>>>>>> +               if (crtc->state->enable)
>>>>>>
>>>>>> I think you really want to check active, instead of enable.
>>>>>
>>>>> Okay, i will check it, thanks.
>>>>>
>>>>>>> +                       num_enabled_crtc++;
>>>>>>> +       }
>>>>>>> +
>>>>>>> +       /* if enable two vop, need to disable dmc */
>>>>>>> +       if ((num_enabled_crtc > 1) && vop->devfreq) {
>>>>>>> +               if (vop->devfreq_event_dev)
>>>>>>> +
>>>>>>> devfreq_event_disable_edev(vop->devfreq_event_dev);
>>>>>>> +               devfreq_suspend_device(vop->devfreq);
>>>>>>> +       }
>>>>>>
>>>>>> This really feels like something that should be handled somewhere
>>>>>> else. I don't fully understand how this works, but it seems like this
>>>>>> dependency should be handled where it actually matters, rather than
>>>>>> building in a seemingly arbitrary restriction in the vop driver.
>>>>>>
>>>>>> Even if this is the best place for it, this needs to be refactored to
>>>>>> eliminate the races that exist now.
>>>>>>
>>>>>> Sean
>>>>>>
>>>>>>>           return 0;
>>>>>>>
>>>>>>>    err_disable_aclk:
>>>>>>> @@ -489,17 +549,31 @@ err_disable_hclk:
>>>>>>>           clk_disable(vop->hclk);
>>>>>>>    err_put_pm_runtime:
>>>>>>>           pm_runtime_put_sync(vop->dev);
>>>>>>> +       vop->vop_switch_status = 0;
>>>>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>>>>>           return ret;
>>>>>>>    }
>>>>>>>
>>>>>>>    static void vop_crtc_disable(struct drm_crtc *crtc)
>>>>>>>    {
>>>>>>>           struct vop *vop = to_vop(crtc);
>>>>>>> +       int num_enabled_crtc = 0;
>>>>>>>           int i;
>>>>>>>
>>>>>>>           WARN_ON(vop->event);
>>>>>>>
>>>>>>>           /*
>>>>>>> +        * if in dmc scaling frequency process, wait until it finish
>>>>>>> +        * use 200ms as timeout time.
>>>>>>> +        */
>>>>>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>>>>>> +                               !vop->dmc_in_process, HZ / 5))
>>>>>>> +               dev_warn(vop->dev,
>>>>>>> +                        "Timeout waiting for dmc when vop disable\n");
>>>>>>> +
>>>>>>> +       vop->vop_switch_status = 1;
>>>>>>> +
>>>>>>> +       /*
>>>>>>>            * We need to make sure that all windows are disabled before
>>>>>>> we
>>>>>>>            * disable that crtc. Otherwise we might try to scan from a
>>>>>>> destroyed
>>>>>>>            * buffer later.
>>>>>>> @@ -555,6 +629,24 @@ static void vop_crtc_disable(struct drm_crtc
>>>>>>> *crtc)
>>>>>>>                   spin_unlock_irq(&crtc->dev->event_lock);
>>>>>>>
>>>>>>>                   crtc->state->event = NULL;
>>>>>>> +
>>>>>>> +       vop->vop_switch_status = 0;
>>>>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>>>>> +
>>>>>>> +       /* check how many VOPs in use now */
>>>>>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>>>>>> +               if (crtc->state->enable)
>>>>>>> +                       num_enabled_crtc++;
>>>>>>> +       }
>>>>>>> +
>>>>>>> +       /*
>>>>>>> +        * if num_enabled_crtc = 1 now, it means 2 vop enabled
>>>>>>> +        * change to 1 vop enabled  need to enable dmc again.
>>>>>>> +        */
>>>>>>> +       if ((num_enabled_crtc == 1) && vop->devfreq) {
>>>>>>> +               if (vop->devfreq_event_dev)
>>>>>>> +
>>>>>>> devfreq_event_enable_edev(vop->devfreq_event_dev);
>>>>>>> +               devfreq_resume_device(vop->devfreq);
>>>>>>>           }
>>>>>>>    }
>>>>>>>
>>>>>>> @@ -1413,6 +1505,8 @@ static int vop_bind(struct device *dev, struct
>>>>>>> device *master, void *data)
>>>>>>>           struct drm_device *drm_dev = data;
>>>>>>>           struct vop *vop;
>>>>>>>           struct resource *res;
>>>>>>> +       struct devfreq *devfreq;
>>>>>>> +       struct devfreq_event_dev *event_dev;
>>>>>>>           size_t alloc_size;
>>>>>>>           int ret, irq;
>>>>>>>
>>>>>>> @@ -1474,6 +1568,28 @@ static int vop_bind(struct device *dev, struct
>>>>>>> device *master, void *data)
>>>>>>>                   return ret;
>>>>>>>
>>>>>>>           pm_runtime_enable(&pdev->dev);
>>>>>>> +
>>>>>>> +       init_waitqueue_head(&vop->wait_vop_switch_queue);
>>>>>>> +       vop->vop_switch_status = 0;
>>>>>>> +       init_waitqueue_head(&vop->wait_dmc_queue);
>>>>>>> +       vop->dmc_in_process = 0;
>>>>>>> +
>>>>>>> +       devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
>>>>>>> +       if (IS_ERR(devfreq))
>>>>>>> +               goto out;
>>>>>>> +
>>>>>>> +       vop->devfreq = devfreq;
>>>>>>> +       vop->dmc_nb.notifier_call = dmc_notify;
>>>>>>> +       devfreq_register_notifier(vop->devfreq, &vop->dmc_nb,
>>>>>>> +                                 DEVFREQ_TRANSITION_NOTIFIER);
>>>>>>> +
>>>>>>> +       event_dev =
>>>>>>> devfreq_event_get_edev_by_phandle(vop->devfreq->dev.parent,
>>>>>>> +                                                     0);
>>>>>>> +       if (IS_ERR(event_dev))
>>>>>>> +               goto out;
>>>>>>> +
>>>>>>> +       vop->devfreq_event_dev = event_dev;
>>>>>>> +out:
>>>>>>>           return 0;
>>>>>>>    }
>>>>>>>
>>>>>>> --
>>>>>>> 2.6.6
>>>>>>>
>>>>>>
>>>>> --
>>>>> Lin Huang
>>>>>
>>>>>
>>>>
>>>>
>>>
>>> --
>>> Lin Huang
>>>
>>>

Re: [PATCH v10 5/5] drm/rockchip: Add dmc notifier in vop driver

[dbasehore .]

On Tue, Sep 6, 2016 at 10:18 AM, Sean Paul <seanpaul@google.com> wrote:
> On Mon, Sep 5, 2016 at 1:06 AM, Lin Huang <hl@rock-chips.com> wrote:
>> when in ddr frequency scaling process, vop can not do enable or
>> disable operation, since in dcf we check vop clock to see whether
>> vop work. If vop work, dcf do ddr frequency scaling when vop
>> in vblank status, and we need to read vop register to check whether
>> vop go into vblank status. If vop not work, dcf can do ddr frequency
>> any time. So when do ddr frequency scaling, you disabled or enable
>> vop, there may two bad thing happen: 1, the panel flicker(when vop from
>> disable status change to enable). 2, kernel hang (when vop from enable
>> status change to disable, dcf need to read vblank status, but if you disable
>> vop clock, it can not get the status, it will lead soc dead) So we need
>> register to devfreq notifier, and we can get the dmc status. Also, when
>> there have two vop enabled, we need to disable dmc, since dcf only base
>> on one vop vblank time, so the other panel will flicker when do ddr
>> frequency scaling.
>>
>> Signed-off-by: Lin Huang <hl@rock-chips.com>
>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
>> ---
>> Changes in v10:
>> - None
>>
>> Changes in v9:
>> - None
>>
>> Changes in v8:
>> - None
>>
>> Changes in v7:
>> - None
>>
>> Changes in v6:
>> - fix a build error
>>
>> Changes in v5:
>> - improve some nits
>>
>> Changes in v4:
>> - register notifier to devfreq_register_notifier
>> - use DEVFREQ_PRECHANGE and DEVFREQ_POSTCHANGE to get dmc status
>> - when two vop enable, disable dmc
>> - when two vop back to one vop, enable dmc
>>
>> Changes in v3:
>> - when do vop eanble/disable, dmc will wait until it finish
>>
>> Changes in v2:
>> - None
>>
>> Changes in v1:
>> - use wait_event instead usleep
>>
>>  drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 116 ++++++++++++++++++++++++++++
>>  1 file changed, 116 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> index efbc41a..a73f3aa 100644
>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> @@ -19,6 +19,8 @@
>>  #include <drm/drm_crtc_helper.h>
>>  #include <drm/drm_plane_helper.h>
>>
>> +#include <linux/devfreq.h>
>> +#include <linux/devfreq-event.h>
>>  #include <linux/kernel.h>
>>  #include <linux/module.h>
>>  #include <linux/platform_device.h>
>> @@ -118,6 +120,13 @@ struct vop {
>>
>>         const struct vop_data *data;
>>
>> +       struct devfreq *devfreq;
>> +       struct devfreq_event_dev *devfreq_event_dev;
>> +       struct notifier_block dmc_nb;
>> +       int dmc_in_process;
>> +       int vop_switch_status;
>> +       wait_queue_head_t wait_dmc_queue;
>> +       wait_queue_head_t wait_vop_switch_queue;
>>         uint32_t *regsbak;
>>         void __iomem *regs;
>>
>> @@ -428,11 +437,47 @@ static void vop_dsp_hold_valid_irq_disable(struct vop *vop)
>>         spin_unlock_irqrestore(&vop->irq_lock, flags);
>>  }
>>
>> +static int dmc_notify(struct notifier_block *nb, unsigned long event,
>> +                     void *data)
>> +{
>> +       struct vop *vop = container_of(nb, struct vop, dmc_nb);
>> +
>> +       if (event == DEVFREQ_PRECHANGE) {
>> +               /*
>> +                * check if vop in enable or disable process,
>> +                * if yes, wait until it finishes, use 200ms as
>> +                * timeout.
>> +                */
>> +               if (!wait_event_timeout(vop->wait_vop_switch_queue,
>> +                                       !vop->vop_switch_status, HZ / 5))
>> +                       dev_warn(vop->dev,
>> +                                "Timeout waiting for vop swtich status\n");
>> +               vop->dmc_in_process = 1;
>> +       } else if (event == DEVFREQ_POSTCHANGE) {
>> +               vop->dmc_in_process = 0;
>> +               wake_up(&vop->wait_dmc_queue);
>> +       }
>> +
>> +       return NOTIFY_OK;
>> +}
>> +
>>  static int vop_enable(struct drm_crtc *crtc)
>>  {
>>         struct vop *vop = to_vop(crtc);
>> +       int num_enabled_crtc = 0;
>>         int ret;
>>
>> +       /*
>> +        * if in dmc scaling frequency process, wait until it finishes
>> +        * use 200ms as timeout time.
>> +        */
>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>> +                               !vop->dmc_in_process, HZ / 5))
>> +               dev_warn(vop->dev,
>> +                        "Timeout waiting for dmc when vop enable\n");
>> +
>
>
> This wait_event_timeout code is terribly racey (same goes above and below).
>
>
>> +       vop->vop_switch_status = 1;
>> +
>>         ret = pm_runtime_get_sync(vop->dev);
>>         if (ret < 0) {
>>                 dev_err(vop->dev, "failed to get pm runtime: %d\n", ret);
>> @@ -479,6 +524,21 @@ static int vop_enable(struct drm_crtc *crtc)
>>
>>         drm_crtc_vblank_on(crtc);
>>
>> +       vop->vop_switch_status = 0;
>> +       wake_up(&vop->wait_vop_switch_queue);
>> +
>> +       /* check how many VOPs in use now */
>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>> +               if (crtc->state->enable)
>
> I think you really want to check active, instead of enable.
>
>> +                       num_enabled_crtc++;
>> +       }
>> +
>> +       /* if enable two vop, need to disable dmc */
>> +       if ((num_enabled_crtc > 1) && vop->devfreq) {
>> +               if (vop->devfreq_event_dev)
>> +                       devfreq_event_disable_edev(vop->devfreq_event_dev);
>> +               devfreq_suspend_device(vop->devfreq);
>> +       }
>
> This really feels like something that should be handled somewhere
> else. I don't fully understand how this works, but it seems like this
> dependency should be handled where it actually matters, rather than
> building in a seemingly arbitrary restriction in the vop driver.
>
> Even if this is the best place for it, this needs to be refactored to
> eliminate the races that exist now.
>
> Sean

DMC transitions can't happen when there is more than one display. You
would have to synchronize with more than one vblank on the DCF (which
actually changes the DDR frequency), and that's probably not going to
happen.

If this code should be done somewhere else, it needs to still be able
to check the number of displays and avoid race conditions with
displays getting enabled or disabled. I don't know enough about DRM to
know if that's possible outside of this code.

>
>>         return 0;
>>
>>  err_disable_aclk:
>> @@ -489,17 +549,31 @@ err_disable_hclk:
>>         clk_disable(vop->hclk);
>>  err_put_pm_runtime:
>>         pm_runtime_put_sync(vop->dev);
>> +       vop->vop_switch_status = 0;
>> +       wake_up(&vop->wait_vop_switch_queue);
>>         return ret;
>>  }
>>
>>  static void vop_crtc_disable(struct drm_crtc *crtc)
>>  {
>>         struct vop *vop = to_vop(crtc);
>> +       int num_enabled_crtc = 0;
>>         int i;
>>
>>         WARN_ON(vop->event);
>>
>>         /*
>> +        * if in dmc scaling frequency process, wait until it finish
>> +        * use 200ms as timeout time.
>> +        */
>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>> +                               !vop->dmc_in_process, HZ / 5))
>> +               dev_warn(vop->dev,
>> +                        "Timeout waiting for dmc when vop disable\n");
>> +
>> +       vop->vop_switch_status = 1;
>> +
>> +       /*
>>          * We need to make sure that all windows are disabled before we
>>          * disable that crtc. Otherwise we might try to scan from a destroyed
>>          * buffer later.
>> @@ -555,6 +629,24 @@ static void vop_crtc_disable(struct drm_crtc *crtc)
>>                 spin_unlock_irq(&crtc->dev->event_lock);
>>
>>                 crtc->state->event = NULL;
>> +
>> +       vop->vop_switch_status = 0;
>> +       wake_up(&vop->wait_vop_switch_queue);
>> +
>> +       /* check how many VOPs in use now */
>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>> +               if (crtc->state->enable)
>> +                       num_enabled_crtc++;
>> +       }
>> +
>> +       /*
>> +        * if num_enabled_crtc = 1 now, it means 2 vop enabled
>> +        * change to 1 vop enabled  need to enable dmc again.
>> +        */
>> +       if ((num_enabled_crtc == 1) && vop->devfreq) {
>> +               if (vop->devfreq_event_dev)
>> +                       devfreq_event_enable_edev(vop->devfreq_event_dev);
>> +               devfreq_resume_device(vop->devfreq);
>>         }
>>  }
>>
>> @@ -1413,6 +1505,8 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
>>         struct drm_device *drm_dev = data;
>>         struct vop *vop;
>>         struct resource *res;
>> +       struct devfreq *devfreq;
>> +       struct devfreq_event_dev *event_dev;
>>         size_t alloc_size;
>>         int ret, irq;
>>
>> @@ -1474,6 +1568,28 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
>>                 return ret;
>>
>>         pm_runtime_enable(&pdev->dev);
>> +
>> +       init_waitqueue_head(&vop->wait_vop_switch_queue);
>> +       vop->vop_switch_status = 0;
>> +       init_waitqueue_head(&vop->wait_dmc_queue);
>> +       vop->dmc_in_process = 0;
>> +
>> +       devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
>> +       if (IS_ERR(devfreq))
>> +               goto out;
>> +
>> +       vop->devfreq = devfreq;
>> +       vop->dmc_nb.notifier_call = dmc_notify;
>> +       devfreq_register_notifier(vop->devfreq, &vop->dmc_nb,
>> +                                 DEVFREQ_TRANSITION_NOTIFIER);
>> +
>> +       event_dev = devfreq_event_get_edev_by_phandle(vop->devfreq->dev.parent,
>> +                                                     0);
>> +       if (IS_ERR(event_dev))
>> +               goto out;
>> +
>> +       vop->devfreq_event_dev = event_dev;
>> +out:
>>         return 0;
>>  }
>>
>> --
>> 2.6.6
>>

Re: [PATCH v10 5/5] drm/rockchip: Add dmc notifier in vop driver

[Sean Paul]

On Wed, Sep 7, 2016 at 2:13 PM, dbasehore . <dbasehore@chromium.org> wrote:
> On Tue, Sep 6, 2016 at 10:18 AM, Sean Paul <seanpaul@google.com> wrote:
>> On Mon, Sep 5, 2016 at 1:06 AM, Lin Huang <hl@rock-chips.com> wrote:
>>> when in ddr frequency scaling process, vop can not do enable or
>>> disable operation, since in dcf we check vop clock to see whether
>>> vop work. If vop work, dcf do ddr frequency scaling when vop
>>> in vblank status, and we need to read vop register to check whether
>>> vop go into vblank status. If vop not work, dcf can do ddr frequency
>>> any time. So when do ddr frequency scaling, you disabled or enable
>>> vop, there may two bad thing happen: 1, the panel flicker(when vop from
>>> disable status change to enable). 2, kernel hang (when vop from enable
>>> status change to disable, dcf need to read vblank status, but if you disable
>>> vop clock, it can not get the status, it will lead soc dead) So we need
>>> register to devfreq notifier, and we can get the dmc status. Also, when
>>> there have two vop enabled, we need to disable dmc, since dcf only base
>>> on one vop vblank time, so the other panel will flicker when do ddr
>>> frequency scaling.
>>>
>>> Signed-off-by: Lin Huang <hl@rock-chips.com>
>>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
>>> ---
>>> Changes in v10:
>>> - None
>>>
>>> Changes in v9:
>>> - None
>>>
>>> Changes in v8:
>>> - None
>>>
>>> Changes in v7:
>>> - None
>>>
>>> Changes in v6:
>>> - fix a build error
>>>
>>> Changes in v5:
>>> - improve some nits
>>>
>>> Changes in v4:
>>> - register notifier to devfreq_register_notifier
>>> - use DEVFREQ_PRECHANGE and DEVFREQ_POSTCHANGE to get dmc status
>>> - when two vop enable, disable dmc
>>> - when two vop back to one vop, enable dmc
>>>
>>> Changes in v3:
>>> - when do vop eanble/disable, dmc will wait until it finish
>>>
>>> Changes in v2:
>>> - None
>>>
>>> Changes in v1:
>>> - use wait_event instead usleep
>>>
>>>  drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 116 ++++++++++++++++++++++++++++
>>>  1 file changed, 116 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>> index efbc41a..a73f3aa 100644
>>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>> @@ -19,6 +19,8 @@
>>>  #include <drm/drm_crtc_helper.h>
>>>  #include <drm/drm_plane_helper.h>
>>>
>>> +#include <linux/devfreq.h>
>>> +#include <linux/devfreq-event.h>
>>>  #include <linux/kernel.h>
>>>  #include <linux/module.h>
>>>  #include <linux/platform_device.h>
>>> @@ -118,6 +120,13 @@ struct vop {
>>>
>>>         const struct vop_data *data;
>>>
>>> +       struct devfreq *devfreq;
>>> +       struct devfreq_event_dev *devfreq_event_dev;
>>> +       struct notifier_block dmc_nb;
>>> +       int dmc_in_process;
>>> +       int vop_switch_status;
>>> +       wait_queue_head_t wait_dmc_queue;
>>> +       wait_queue_head_t wait_vop_switch_queue;
>>>         uint32_t *regsbak;
>>>         void __iomem *regs;
>>>
>>> @@ -428,11 +437,47 @@ static void vop_dsp_hold_valid_irq_disable(struct vop *vop)
>>>         spin_unlock_irqrestore(&vop->irq_lock, flags);
>>>  }
>>>
>>> +static int dmc_notify(struct notifier_block *nb, unsigned long event,
>>> +                     void *data)
>>> +{
>>> +       struct vop *vop = container_of(nb, struct vop, dmc_nb);
>>> +
>>> +       if (event == DEVFREQ_PRECHANGE) {
>>> +               /*
>>> +                * check if vop in enable or disable process,
>>> +                * if yes, wait until it finishes, use 200ms as
>>> +                * timeout.
>>> +                */
>>> +               if (!wait_event_timeout(vop->wait_vop_switch_queue,
>>> +                                       !vop->vop_switch_status, HZ / 5))
>>> +                       dev_warn(vop->dev,
>>> +                                "Timeout waiting for vop swtich status\n");
>>> +               vop->dmc_in_process = 1;
>>> +       } else if (event == DEVFREQ_POSTCHANGE) {
>>> +               vop->dmc_in_process = 0;
>>> +               wake_up(&vop->wait_dmc_queue);
>>> +       }
>>> +
>>> +       return NOTIFY_OK;
>>> +}
>>> +
>>>  static int vop_enable(struct drm_crtc *crtc)
>>>  {
>>>         struct vop *vop = to_vop(crtc);
>>> +       int num_enabled_crtc = 0;
>>>         int ret;
>>>
>>> +       /*
>>> +        * if in dmc scaling frequency process, wait until it finishes
>>> +        * use 200ms as timeout time.
>>> +        */
>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>> +                               !vop->dmc_in_process, HZ / 5))
>>> +               dev_warn(vop->dev,
>>> +                        "Timeout waiting for dmc when vop enable\n");
>>> +
>>
>>
>> This wait_event_timeout code is terribly racey (same goes above and below).
>>
>>
>>> +       vop->vop_switch_status = 1;
>>> +
>>>         ret = pm_runtime_get_sync(vop->dev);
>>>         if (ret < 0) {
>>>                 dev_err(vop->dev, "failed to get pm runtime: %d\n", ret);
>>> @@ -479,6 +524,21 @@ static int vop_enable(struct drm_crtc *crtc)
>>>
>>>         drm_crtc_vblank_on(crtc);
>>>
>>> +       vop->vop_switch_status = 0;
>>> +       wake_up(&vop->wait_vop_switch_queue);
>>> +
>>> +       /* check how many VOPs in use now */
>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>> +               if (crtc->state->enable)
>>
>> I think you really want to check active, instead of enable.
>>
>>> +                       num_enabled_crtc++;
>>> +       }
>>> +
>>> +       /* if enable two vop, need to disable dmc */
>>> +       if ((num_enabled_crtc > 1) && vop->devfreq) {
>>> +               if (vop->devfreq_event_dev)
>>> +                       devfreq_event_disable_edev(vop->devfreq_event_dev);
>>> +               devfreq_suspend_device(vop->devfreq);
>>> +       }
>>
>> This really feels like something that should be handled somewhere
>> else. I don't fully understand how this works, but it seems like this
>> dependency should be handled where it actually matters, rather than
>> building in a seemingly arbitrary restriction in the vop driver.
>>
>> Even if this is the best place for it, this needs to be refactored to
>> eliminate the races that exist now.
>>
>> Sean
>
> DMC transitions can't happen when there is more than one display. You
> would have to synchronize with more than one vblank on the DCF (which
> actually changes the DDR frequency), and that's probably not going to
> happen.
>
> If this code should be done somewhere else, it needs to still be able
> to check the number of displays and avoid race conditions with
> displays getting enabled or disabled. I don't know enough about DRM to
> know if that's possible outside of this code.
>

Yeah, so I suppose that's another race, since we aren't necessarily
guaranteed to be enabling/disabling the crtcs in the order this patch
assumes.

I think we can probably handle this better by doing this up a level
where we have a more global view of which vops are enabled/disabled
and the order in which they will be processed.

I'm working on this now, stay tuned.

Sean



>>
>>>         return 0;
>>>
>>>  err_disable_aclk:
>>> @@ -489,17 +549,31 @@ err_disable_hclk:
>>>         clk_disable(vop->hclk);
>>>  err_put_pm_runtime:
>>>         pm_runtime_put_sync(vop->dev);
>>> +       vop->vop_switch_status = 0;
>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>         return ret;
>>>  }
>>>
>>>  static void vop_crtc_disable(struct drm_crtc *crtc)
>>>  {
>>>         struct vop *vop = to_vop(crtc);
>>> +       int num_enabled_crtc = 0;
>>>         int i;
>>>
>>>         WARN_ON(vop->event);
>>>
>>>         /*
>>> +        * if in dmc scaling frequency process, wait until it finish
>>> +        * use 200ms as timeout time.
>>> +        */
>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>> +                               !vop->dmc_in_process, HZ / 5))
>>> +               dev_warn(vop->dev,
>>> +                        "Timeout waiting for dmc when vop disable\n");
>>> +
>>> +       vop->vop_switch_status = 1;
>>> +
>>> +       /*
>>>          * We need to make sure that all windows are disabled before we
>>>          * disable that crtc. Otherwise we might try to scan from a destroyed
>>>          * buffer later.
>>> @@ -555,6 +629,24 @@ static void vop_crtc_disable(struct drm_crtc *crtc)
>>>                 spin_unlock_irq(&crtc->dev->event_lock);
>>>
>>>                 crtc->state->event = NULL;
>>> +
>>> +       vop->vop_switch_status = 0;
>>> +       wake_up(&vop->wait_vop_switch_queue);
>>> +
>>> +       /* check how many VOPs in use now */
>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>> +               if (crtc->state->enable)
>>> +                       num_enabled_crtc++;
>>> +       }
>>> +
>>> +       /*
>>> +        * if num_enabled_crtc = 1 now, it means 2 vop enabled
>>> +        * change to 1 vop enabled  need to enable dmc again.
>>> +        */
>>> +       if ((num_enabled_crtc == 1) && vop->devfreq) {
>>> +               if (vop->devfreq_event_dev)
>>> +                       devfreq_event_enable_edev(vop->devfreq_event_dev);
>>> +               devfreq_resume_device(vop->devfreq);
>>>         }
>>>  }
>>>
>>> @@ -1413,6 +1505,8 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
>>>         struct drm_device *drm_dev = data;
>>>         struct vop *vop;
>>>         struct resource *res;
>>> +       struct devfreq *devfreq;
>>> +       struct devfreq_event_dev *event_dev;
>>>         size_t alloc_size;
>>>         int ret, irq;
>>>
>>> @@ -1474,6 +1568,28 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
>>>                 return ret;
>>>
>>>         pm_runtime_enable(&pdev->dev);
>>> +
>>> +       init_waitqueue_head(&vop->wait_vop_switch_queue);
>>> +       vop->vop_switch_status = 0;
>>> +       init_waitqueue_head(&vop->wait_dmc_queue);
>>> +       vop->dmc_in_process = 0;
>>> +
>>> +       devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
>>> +       if (IS_ERR(devfreq))
>>> +               goto out;
>>> +
>>> +       vop->devfreq = devfreq;
>>> +       vop->dmc_nb.notifier_call = dmc_notify;
>>> +       devfreq_register_notifier(vop->devfreq, &vop->dmc_nb,
>>> +                                 DEVFREQ_TRANSITION_NOTIFIER);
>>> +
>>> +       event_dev = devfreq_event_get_edev_by_phandle(vop->devfreq->dev.parent,
>>> +                                                     0);
>>> +       if (IS_ERR(event_dev))
>>> +               goto out;
>>> +
>>> +       vop->devfreq_event_dev = event_dev;
>>> +out:
>>>         return 0;
>>>  }
>>>
>>> --
>>> 2.6.6
>>>

Re: [PATCH v10 5/5] drm/rockchip: Add dmc notifier in vop driver

[dbasehore .]

On Wed, Sep 7, 2016 at 1:31 PM, Sean Paul <seanpaul@google.com> wrote:
> On Wed, Sep 7, 2016 at 2:13 PM, dbasehore . <dbasehore@chromium.org> wrote:
>> On Tue, Sep 6, 2016 at 10:18 AM, Sean Paul <seanpaul@google.com> wrote:
>>> On Mon, Sep 5, 2016 at 1:06 AM, Lin Huang <hl@rock-chips.com> wrote:
>>>> when in ddr frequency scaling process, vop can not do enable or
>>>> disable operation, since in dcf we check vop clock to see whether
>>>> vop work. If vop work, dcf do ddr frequency scaling when vop
>>>> in vblank status, and we need to read vop register to check whether
>>>> vop go into vblank status. If vop not work, dcf can do ddr frequency
>>>> any time. So when do ddr frequency scaling, you disabled or enable
>>>> vop, there may two bad thing happen: 1, the panel flicker(when vop from
>>>> disable status change to enable). 2, kernel hang (when vop from enable
>>>> status change to disable, dcf need to read vblank status, but if you disable
>>>> vop clock, it can not get the status, it will lead soc dead) So we need
>>>> register to devfreq notifier, and we can get the dmc status. Also, when
>>>> there have two vop enabled, we need to disable dmc, since dcf only base
>>>> on one vop vblank time, so the other panel will flicker when do ddr
>>>> frequency scaling.
>>>>
>>>> Signed-off-by: Lin Huang <hl@rock-chips.com>
>>>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
>>>> ---
>>>> Changes in v10:
>>>> - None
>>>>
>>>> Changes in v9:
>>>> - None
>>>>
>>>> Changes in v8:
>>>> - None
>>>>
>>>> Changes in v7:
>>>> - None
>>>>
>>>> Changes in v6:
>>>> - fix a build error
>>>>
>>>> Changes in v5:
>>>> - improve some nits
>>>>
>>>> Changes in v4:
>>>> - register notifier to devfreq_register_notifier
>>>> - use DEVFREQ_PRECHANGE and DEVFREQ_POSTCHANGE to get dmc status
>>>> - when two vop enable, disable dmc
>>>> - when two vop back to one vop, enable dmc
>>>>
>>>> Changes in v3:
>>>> - when do vop eanble/disable, dmc will wait until it finish
>>>>
>>>> Changes in v2:
>>>> - None
>>>>
>>>> Changes in v1:
>>>> - use wait_event instead usleep
>>>>
>>>>  drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 116 ++++++++++++++++++++++++++++
>>>>  1 file changed, 116 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>> index efbc41a..a73f3aa 100644
>>>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>>>> @@ -19,6 +19,8 @@
>>>>  #include <drm/drm_crtc_helper.h>
>>>>  #include <drm/drm_plane_helper.h>
>>>>
>>>> +#include <linux/devfreq.h>
>>>> +#include <linux/devfreq-event.h>
>>>>  #include <linux/kernel.h>
>>>>  #include <linux/module.h>
>>>>  #include <linux/platform_device.h>
>>>> @@ -118,6 +120,13 @@ struct vop {
>>>>
>>>>         const struct vop_data *data;
>>>>
>>>> +       struct devfreq *devfreq;
>>>> +       struct devfreq_event_dev *devfreq_event_dev;
>>>> +       struct notifier_block dmc_nb;
>>>> +       int dmc_in_process;
>>>> +       int vop_switch_status;
>>>> +       wait_queue_head_t wait_dmc_queue;
>>>> +       wait_queue_head_t wait_vop_switch_queue;
>>>>         uint32_t *regsbak;
>>>>         void __iomem *regs;
>>>>
>>>> @@ -428,11 +437,47 @@ static void vop_dsp_hold_valid_irq_disable(struct vop *vop)
>>>>         spin_unlock_irqrestore(&vop->irq_lock, flags);
>>>>  }
>>>>
>>>> +static int dmc_notify(struct notifier_block *nb, unsigned long event,
>>>> +                     void *data)
>>>> +{
>>>> +       struct vop *vop = container_of(nb, struct vop, dmc_nb);
>>>> +
>>>> +       if (event == DEVFREQ_PRECHANGE) {
>>>> +               /*
>>>> +                * check if vop in enable or disable process,
>>>> +                * if yes, wait until it finishes, use 200ms as
>>>> +                * timeout.
>>>> +                */
>>>> +               if (!wait_event_timeout(vop->wait_vop_switch_queue,
>>>> +                                       !vop->vop_switch_status, HZ / 5))
>>>> +                       dev_warn(vop->dev,
>>>> +                                "Timeout waiting for vop swtich status\n");
>>>> +               vop->dmc_in_process = 1;
>>>> +       } else if (event == DEVFREQ_POSTCHANGE) {
>>>> +               vop->dmc_in_process = 0;
>>>> +               wake_up(&vop->wait_dmc_queue);
>>>> +       }
>>>> +
>>>> +       return NOTIFY_OK;
>>>> +}
>>>> +
>>>>  static int vop_enable(struct drm_crtc *crtc)
>>>>  {
>>>>         struct vop *vop = to_vop(crtc);
>>>> +       int num_enabled_crtc = 0;
>>>>         int ret;
>>>>
>>>> +       /*
>>>> +        * if in dmc scaling frequency process, wait until it finishes
>>>> +        * use 200ms as timeout time.
>>>> +        */
>>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>>> +                               !vop->dmc_in_process, HZ / 5))
>>>> +               dev_warn(vop->dev,
>>>> +                        "Timeout waiting for dmc when vop enable\n");
>>>> +
>>>
>>>
>>> This wait_event_timeout code is terribly racey (same goes above and below).
>>>
>>>
>>>> +       vop->vop_switch_status = 1;
>>>> +
>>>>         ret = pm_runtime_get_sync(vop->dev);
>>>>         if (ret < 0) {
>>>>                 dev_err(vop->dev, "failed to get pm runtime: %d\n", ret);
>>>> @@ -479,6 +524,21 @@ static int vop_enable(struct drm_crtc *crtc)
>>>>
>>>>         drm_crtc_vblank_on(crtc);
>>>>
>>>> +       vop->vop_switch_status = 0;
>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>> +
>>>> +       /* check how many VOPs in use now */
>>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>>> +               if (crtc->state->enable)
>>>
>>> I think you really want to check active, instead of enable.
>>>
>>>> +                       num_enabled_crtc++;
>>>> +       }
>>>> +
>>>> +       /* if enable two vop, need to disable dmc */
>>>> +       if ((num_enabled_crtc > 1) && vop->devfreq) {
>>>> +               if (vop->devfreq_event_dev)
>>>> +                       devfreq_event_disable_edev(vop->devfreq_event_dev);
>>>> +               devfreq_suspend_device(vop->devfreq);
>>>> +       }
>>>
>>> This really feels like something that should be handled somewhere
>>> else. I don't fully understand how this works, but it seems like this
>>> dependency should be handled where it actually matters, rather than
>>> building in a seemingly arbitrary restriction in the vop driver.
>>>
>>> Even if this is the best place for it, this needs to be refactored to
>>> eliminate the races that exist now.
>>>
>>> Sean
>>
>> DMC transitions can't happen when there is more than one display. You
>> would have to synchronize with more than one vblank on the DCF (which
>> actually changes the DDR frequency), and that's probably not going to
>> happen.
>>
>> If this code should be done somewhere else, it needs to still be able
>> to check the number of displays and avoid race conditions with
>> displays getting enabled or disabled. I don't know enough about DRM to
>> know if that's possible outside of this code.
>>
>
> Yeah, so I suppose that's another race, since we aren't necessarily
> guaranteed to be enabling/disabling the crtcs in the order this patch
> assumes.
>
> I think we can probably handle this better by doing this up a level
> where we have a more global view of which vops are enabled/disabled
> and the order in which they will be processed.
>
> I'm working on this now, stay tuned.
>
> Sean
>

Can there be concurrent calls to vop enable/disable for different
displays? If so, we could also hit a race between calculating
num_enabled_crtc and calling devfreq_suspend_device. That section
might have to be protected by a lock.

>
>
>>>
>>>>         return 0;
>>>>
>>>>  err_disable_aclk:
>>>> @@ -489,17 +549,31 @@ err_disable_hclk:
>>>>         clk_disable(vop->hclk);
>>>>  err_put_pm_runtime:
>>>>         pm_runtime_put_sync(vop->dev);
>>>> +       vop->vop_switch_status = 0;
>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>>         return ret;
>>>>  }
>>>>
>>>>  static void vop_crtc_disable(struct drm_crtc *crtc)
>>>>  {
>>>>         struct vop *vop = to_vop(crtc);
>>>> +       int num_enabled_crtc = 0;
>>>>         int i;
>>>>
>>>>         WARN_ON(vop->event);
>>>>
>>>>         /*
>>>> +        * if in dmc scaling frequency process, wait until it finish
>>>> +        * use 200ms as timeout time.
>>>> +        */
>>>> +       if (!wait_event_timeout(vop->wait_dmc_queue,
>>>> +                               !vop->dmc_in_process, HZ / 5))
>>>> +               dev_warn(vop->dev,
>>>> +                        "Timeout waiting for dmc when vop disable\n");
>>>> +
>>>> +       vop->vop_switch_status = 1;
>>>> +
>>>> +       /*
>>>>          * We need to make sure that all windows are disabled before we
>>>>          * disable that crtc. Otherwise we might try to scan from a destroyed
>>>>          * buffer later.
>>>> @@ -555,6 +629,24 @@ static void vop_crtc_disable(struct drm_crtc *crtc)
>>>>                 spin_unlock_irq(&crtc->dev->event_lock);
>>>>
>>>>                 crtc->state->event = NULL;
>>>> +
>>>> +       vop->vop_switch_status = 0;
>>>> +       wake_up(&vop->wait_vop_switch_queue);
>>>> +
>>>> +       /* check how many VOPs in use now */
>>>> +       drm_for_each_crtc(crtc, vop->drm_dev) {
>>>> +               if (crtc->state->enable)
>>>> +                       num_enabled_crtc++;
>>>> +       }
>>>> +
>>>> +       /*
>>>> +        * if num_enabled_crtc = 1 now, it means 2 vop enabled
>>>> +        * change to 1 vop enabled  need to enable dmc again.
>>>> +        */
>>>> +       if ((num_enabled_crtc == 1) && vop->devfreq) {
>>>> +               if (vop->devfreq_event_dev)
>>>> +                       devfreq_event_enable_edev(vop->devfreq_event_dev);
>>>> +               devfreq_resume_device(vop->devfreq);

This is the section I'm referring to.

>>>>         }
>>>>  }
>>>>
>>>> @@ -1413,6 +1505,8 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
>>>>         struct drm_device *drm_dev = data;
>>>>         struct vop *vop;
>>>>         struct resource *res;
>>>> +       struct devfreq *devfreq;
>>>> +       struct devfreq_event_dev *event_dev;
>>>>         size_t alloc_size;
>>>>         int ret, irq;
>>>>
>>>> @@ -1474,6 +1568,28 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
>>>>                 return ret;
>>>>
>>>>         pm_runtime_enable(&pdev->dev);
>>>> +
>>>> +       init_waitqueue_head(&vop->wait_vop_switch_queue);
>>>> +       vop->vop_switch_status = 0;
>>>> +       init_waitqueue_head(&vop->wait_dmc_queue);
>>>> +       vop->dmc_in_process = 0;
>>>> +
>>>> +       devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
>>>> +       if (IS_ERR(devfreq))
>>>> +               goto out;
>>>> +
>>>> +       vop->devfreq = devfreq;
>>>> +       vop->dmc_nb.notifier_call = dmc_notify;
>>>> +       devfreq_register_notifier(vop->devfreq, &vop->dmc_nb,
>>>> +                                 DEVFREQ_TRANSITION_NOTIFIER);
>>>> +
>>>> +       event_dev = devfreq_event_get_edev_by_phandle(vop->devfreq->dev.parent,
>>>> +                                                     0);
>>>> +       if (IS_ERR(event_dev))
>>>> +               goto out;
>>>> +
>>>> +       vop->devfreq_event_dev = event_dev;
>>>> +out:
>>>>         return 0;
>>>>  }
>>>>
>>>> --
>>>> 2.6.6
>>>>

RE: [PATCH v10 5/5] drm/rockchip: Add dmc notifier in vop driver

[MyungJoo Ham]

[-- Attachment #1: Type: text/plain, Size: 2131 bytes --]

> when in ddr frequency scaling process, vop can not do enable or
> disable operation, since in dcf we check vop clock to see whether
> vop work. If vop work, dcf do ddr frequency scaling when vop
> in vblank status, and we need to read vop register to check whether
> vop go into vblank status. If vop not work, dcf can do ddr frequency
> any time. So when do ddr frequency scaling, you disabled or enable
> vop, there may two bad thing happen: 1, the panel flicker(when vop from
> disable status change to enable). 2, kernel hang (when vop from enable
> status change to disable, dcf need to read vblank status, but if you disable
> vop clock, it can not get the status, it will lead soc dead) So we need
> register to devfreq notifier, and we can get the dmc status. Also, when
> there have two vop enabled, we need to disable dmc, since dcf only base
> on one vop vblank time, so the other panel will flicker when do ddr
> frequency scaling.
> 
> Signed-off-by: Lin Huang <hl@rock-chips.com>
> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>


Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>


The code looks fine, but I've just found that I cannot merge this
code as I am not handling drivers/gpu/drm.

Please try to merge this piece into drivers/gpu/drm tree.

For the other 4 piecies (1/5 to 4/5) I'm ok with them. I'm merging them now.


> ---
> Changes in v10:
> - None
> 
> Changes in v9:
> - None
> 
> Changes in v8:
> - None
> 
> Changes in v7:
> - None
> 
> Changes in v6:
> - fix a build error
> 
> Changes in v5:
> - improve some nits
> 
> Changes in v4:
> - register notifier to devfreq_register_notifier
> - use DEVFREQ_PRECHANGE and DEVFREQ_POSTCHANGE to get dmc status
> - when two vop enable, disable dmc
> - when two vop back to one vop, enable dmc
> 
> Changes in v3:
> - when do vop eanble/disable, dmc will wait until it finish
> 
> Changes in v2:
> - None
> 
> Changes in v1:
> - use wait_event instead usleep
> 
>  drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 116 ++++++++++++++++++++++++++++
>  1 file changed, 116 insertions(+)
>