Date:   Thu, 11 Jun 2020 16:47:32 -0500
From:   Suman Anna <s-anna@...com>
To:     Paul Cercueil <paul@...pouillou.net>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Ohad Ben-Cohen <ohad@...ery.com>,
        Arnaud Pouliquen <arnaud.pouliquen@...com>
CC:     <od@...c.me>, <linux-remoteproc@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>
Subject: Re: [PATCH v7 4/5] remoteproc: ingenic: Added remoteproc driver

Hi Paul,

On 5/15/20 5:43 AM, Paul Cercueil wrote:
> This driver is used to boot, communicate with and load firmwares to the
> MIPS co-processor found in the VPU hardware of the JZ47xx SoCs from
> Ingenic.

I have a few comments w.r.t pm_runtime usage in this driver.

> 
> Signed-off-by: Paul Cercueil <paul@...pouillou.net>
> Acked-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> ---
> 
> Notes:
>      v2: Remove exception for always-mapped memories
>      v3: - Use clk_bulk API
>      	- Move device-managed code to its own patch [3/4]
>      	- Move devicetree table right above ingenic_rproc_driver
>      	- Removed #ifdef CONFIG_OF around devicetree table
>      	- Removed .owner = THIS_MODULE in ingenic_rproc_driver
>      	- Removed useless platform_set_drvdata()
>      v4: - Add fix reported by Julia
>      	- Change Kconfig symbol to INGENIC_VPU_RPROC
>      	- Add documentation to struct vpu
>      	- disable_irq_nosync() -> disable_irq()
>      v5: No change
>      v6: Instead of prepare/unprepare callbacks, use PM runtime callbacks
>      v7: - Remove use of of_match_ptr()
>      	- Move Kconfig symbol so that it's in alphabetical order
>      	- Add missing doc for private structure field aux_base
>      	- Don't check for (len <= 0) in da_to_va()
>      	- Add missing \n in dev_info/dev_err messages
> 
>   drivers/remoteproc/Kconfig         |   9 +
>   drivers/remoteproc/Makefile        |   1 +
>   drivers/remoteproc/ingenic_rproc.c | 280 +++++++++++++++++++++++++++++
>   3 files changed, 290 insertions(+)
>   create mode 100644 drivers/remoteproc/ingenic_rproc.c
> 
> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> index fbaed079b299..c4d1731295eb 100644
> --- a/drivers/remoteproc/Kconfig
> +++ b/drivers/remoteproc/Kconfig
> @@ -23,6 +23,15 @@ config IMX_REMOTEPROC
>   
>   	  It's safe to say N here.
>   
> +config INGENIC_VPU_RPROC
> +	tristate "Ingenic JZ47xx VPU remoteproc support"
> +	depends on MIPS || COMPILE_TEST
> +	help
> +	  Say y or m here to support the VPU in the JZ47xx SoCs from Ingenic.
> +
> +	  This can be either built-in or a loadable module.
> +	  If unsure say N.
> +
>   config MTK_SCP
>   	tristate "Mediatek SCP support"
>   	depends on ARCH_MEDIATEK
> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
> index 0effd3825035..e8b886e511f0 100644
> --- a/drivers/remoteproc/Makefile
> +++ b/drivers/remoteproc/Makefile
> @@ -10,6 +10,7 @@ remoteproc-y				+= remoteproc_sysfs.o
>   remoteproc-y				+= remoteproc_virtio.o
>   remoteproc-y				+= remoteproc_elf_loader.o
>   obj-$(CONFIG_IMX_REMOTEPROC)		+= imx_rproc.o
> +obj-$(CONFIG_INGENIC_VPU_RPROC)		+= ingenic_rproc.o
>   obj-$(CONFIG_MTK_SCP)			+= mtk_scp.o mtk_scp_ipi.o
>   obj-$(CONFIG_OMAP_REMOTEPROC)		+= omap_remoteproc.o
>   obj-$(CONFIG_WKUP_M3_RPROC)		+= wkup_m3_rproc.o
> diff --git a/drivers/remoteproc/ingenic_rproc.c b/drivers/remoteproc/ingenic_rproc.c
> new file mode 100644
> index 000000000000..189020d77b25
> --- /dev/null
> +++ b/drivers/remoteproc/ingenic_rproc.c
> @@ -0,0 +1,280 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Ingenic JZ47xx remoteproc driver
> + * Copyright 2019, Paul Cercueil <paul@...pouillou.net>
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/remoteproc.h>
> +
> +#include "remoteproc_internal.h"
> +
> +#define REG_AUX_CTRL		0x0
> +#define REG_AUX_MSG_ACK		0x10
> +#define REG_AUX_MSG		0x14
> +#define REG_CORE_MSG_ACK	0x18
> +#define REG_CORE_MSG		0x1C
> +
> +#define AUX_CTRL_SLEEP		BIT(31)
> +#define AUX_CTRL_MSG_IRQ_EN	BIT(3)
> +#define AUX_CTRL_NMI_RESETS	BIT(2)
> +#define AUX_CTRL_NMI		BIT(1)
> +#define AUX_CTRL_SW_RESET	BIT(0)
> +
> +struct vpu_mem_map {
> +	const char *name;
> +	unsigned int da;
> +};
> +
> +struct vpu_mem_info {
> +	const struct vpu_mem_map *map;
> +	unsigned long len;
> +	void __iomem *base;
> +};
> +
> +static const struct vpu_mem_map vpu_mem_map[] = {
> +	{ "tcsm0", 0x132b0000 },
> +	{ "tcsm1", 0xf4000000 },
> +	{ "sram",  0x132f0000 },
> +};
> +
> +/**
> + * struct vpu - Ingenic VPU remoteproc private structure
> + * @irq: interrupt number
> + * @clks: pointers to the VPU and AUX clocks
> + * @aux_base: raw pointer to the AUX interface registers
> + * @mem_info: array of struct vpu_mem_info, which contain the mapping info of
> + *            each of the external memories
> + * @dev: private pointer to the device
> + */
> +struct vpu {
> +	int irq;
> +	struct clk_bulk_data clks[2];
> +	void __iomem *aux_base;
> +	struct vpu_mem_info mem_info[ARRAY_SIZE(vpu_mem_map)];
> +	struct device *dev;
> +};
> +
> +static int ingenic_rproc_start(struct rproc *rproc)
> +{
> +	struct vpu *vpu = rproc->priv;
> +	u32 ctrl;
> +
> +	enable_irq(vpu->irq);
> +
> +	/* Reset the AUX and enable message IRQ */
> +	ctrl = AUX_CTRL_NMI_RESETS | AUX_CTRL_NMI | AUX_CTRL_MSG_IRQ_EN;
> +	writel(ctrl, vpu->aux_base + REG_AUX_CTRL);
> +
> +	return 0;
> +}
> +
> +static int ingenic_rproc_stop(struct rproc *rproc)
> +{
> +	struct vpu *vpu = rproc->priv;
> +
> +	disable_irq(vpu->irq);
> +
> +	/* Keep AUX in reset mode */
> +	writel(AUX_CTRL_SW_RESET, vpu->aux_base + REG_AUX_CTRL);
> +
> +	return 0;
> +}
> +
> +static void ingenic_rproc_kick(struct rproc *rproc, int vqid)
> +{
> +	struct vpu *vpu = rproc->priv;
> +
> +	writel(vqid, vpu->aux_base + REG_CORE_MSG);
> +}
> +
> +static void *ingenic_rproc_da_to_va(struct rproc *rproc, u64 da, size_t len)
> +{
> +	struct vpu *vpu = rproc->priv;
> +	void __iomem *va = NULL;
> +	unsigned int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(vpu_mem_map); i++) {
> +		const struct vpu_mem_info *info = &vpu->mem_info[i];
> +		const struct vpu_mem_map *map = info->map;
> +
> +		if (da >= map->da && (da + len) < (map->da + info->len)) {
> +			va = info->base + (da - map->da);
> +			break;
> +		}
> +	}
> +
> +	return (__force void *)va;
> +}
> +
> +static struct rproc_ops ingenic_rproc_ops = {
> +	.start = ingenic_rproc_start,
> +	.stop = ingenic_rproc_stop,
> +	.kick = ingenic_rproc_kick,
> +	.da_to_va = ingenic_rproc_da_to_va,
> +};
> +
> +static irqreturn_t vpu_interrupt(int irq, void *data)
> +{
> +	struct rproc *rproc = data;
> +	struct vpu *vpu = rproc->priv;
> +	u32 vring;
> +
> +	vring = readl(vpu->aux_base + REG_AUX_MSG);
> +
> +	/* Ack the interrupt */
> +	writel(0, vpu->aux_base + REG_AUX_MSG_ACK);
> +
> +	return rproc_vq_interrupt(rproc, vring);
> +}
> +
> +static void ingenic_rproc_disable_clks(void *data)
> +{
> +	struct vpu *vpu = data;
> +
> +	pm_runtime_resume(vpu->dev);
> +	pm_runtime_disable(vpu->dev);
> +
> +	clk_bulk_disable_unprepare(ARRAY_SIZE(vpu->clks), vpu->clks);
> +}
> +
> +static int ingenic_rproc_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct resource *mem;
> +	struct rproc *rproc;
> +	struct vpu *vpu;
> +	unsigned int i;
> +	int ret;
> +
> +	rproc = devm_rproc_alloc(dev, "ingenic-vpu",
> +				 &ingenic_rproc_ops, NULL, sizeof(*vpu));
> +	if (!rproc)
> +		return -ENOMEM;
> +
> +	vpu = rproc->priv;
> +	vpu->dev = &pdev->dev;
> +	platform_set_drvdata(pdev, vpu);
> +
> +	mem = platform_get_resource_byname(pdev, IORESOURCE_MEM, "aux");
> +	vpu->aux_base = devm_ioremap_resource(dev, mem);
> +	if (IS_ERR(vpu->aux_base)) {
> +		dev_err(dev, "Failed to ioremap\n");
> +		return PTR_ERR(vpu->aux_base);
> +	}
> +
> +	for (i = 0; i < ARRAY_SIZE(vpu_mem_map); i++) {
> +		mem = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> +						   vpu_mem_map[i].name);
> +
> +		vpu->mem_info[i].base = devm_ioremap_resource(dev, mem);
> +		if (IS_ERR(vpu->mem_info[i].base)) {
> +			ret = PTR_ERR(vpu->mem_info[i].base);
> +			dev_err(dev, "Failed to ioremap\n");
> +			return ret;
> +		}
> +
> +		vpu->mem_info[i].len = resource_size(mem);
> +		vpu->mem_info[i].map = &vpu_mem_map[i];
> +	}
> +
> +	vpu->clks[0].id = "vpu";
> +	vpu->clks[1].id = "aux";
> +
> +	ret = devm_clk_bulk_get(dev, ARRAY_SIZE(vpu->clks), vpu->clks);
> +	if (ret) {
> +		dev_err(dev, "Failed to get clocks\n");
> +		return ret;
> +	}
> +
> +	vpu->irq = platform_get_irq(pdev, 0);
> +	if (vpu->irq < 0)
> +		return vpu->irq;
> +
> +	ret = devm_request_irq(dev, vpu->irq, vpu_interrupt, 0, "VPU", rproc);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to request IRQ\n");
> +		return ret;
> +	}
> +
> +	disable_irq(vpu->irq);
> +
> +	/* The clocks must be enabled for the firmware to be loaded in TCSM */
> +	ret = clk_bulk_prepare_enable(ARRAY_SIZE(vpu->clks), vpu->clks);
> +	if (ret) {
> +		dev_err(dev, "Unable to start clocks\n");
> +		return ret;
> +	}

You are enabling the clocks directly here and also trying to manage them 
through pm_runtime callbacks again.

> +
> +	pm_runtime_irq_safe(dev);

Nothing wrong with this, but this does take an additional reference 
count on the parent device (a bus device for you??), and also implies 
that your clk driver code can all run in atomic context so unless you 
have a strong reason, it is safe to drop this.

> +	pm_runtime_set_active(dev);

The get_sync below would have been sufficient if you had either limited 
the clk API above to just clk_prepare, or you could have moved the whole 
clk API above into your runtime resume callback.

> +	pm_runtime_enable(dev);
> +	pm_runtime_get_sync(dev);

If the intention was to increment the usage count with the above 
sequence, pm_runtime_get_noresume() is better. But dropping all of the 
above and just using get_sync would have been sufficient.

> +	pm_runtime_use_autosuspend(dev);

I don't see any setting of the autosuspend delay (default value is 0). 
So, you might have as well just not used this at all, and just used 
pm_runtime_put() below.

> +
> +	ret = devm_add_action_or_reset(dev, ingenic_rproc_disable_clks, vpu);
> +	if (ret) {
> +		dev_err(dev, "Unable to register action\n");
> +		goto out_pm_put;
> +	}
> +
> +	ret = devm_rproc_add(dev, rproc);
> +	if (ret) {
> +		dev_err(dev, "Failed to register remote processor\n");
> +		goto out_pm_put;
> +	}

You are using auto-boot, so the firmware loading is an asynchronous 
event and most probably you would run through below sequence first, and 
end up disabling the clocks with an incorrect rpm status.

> +
> +out_pm_put:
> +	pm_runtime_put_autosuspend(dev);

And finally, with the remoteproc core rpm patch, this would all have 
been unnecessary.

> +
> +	return ret;
> +}
> +
> +static const struct of_device_id ingenic_rproc_of_matches[] = {
> +	{ .compatible = "ingenic,jz4770-vpu-rproc", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, ingenic_rproc_of_matches);
> +
> +static int __maybe_unused ingenic_rproc_suspend(struct device *dev)
> +{
> +	struct vpu *vpu = dev_get_drvdata(dev);
> +
> +	clk_bulk_disable(ARRAY_SIZE(vpu->clks), vpu->clks);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused ingenic_rproc_resume(struct device *dev)
> +{
> +	struct vpu *vpu = dev_get_drvdata(dev);
> +
> +	return clk_bulk_enable(ARRAY_SIZE(vpu->clks), vpu->clks);
> +}
> +
> +static const struct dev_pm_ops __maybe_unused ingenic_rproc_pm = {
> +	SET_RUNTIME_PM_OPS(ingenic_rproc_suspend, ingenic_rproc_resume, NULL)
> +};
> +
> +static struct platform_driver ingenic_rproc_driver = {
> +	.probe = ingenic_rproc_probe,
> +	.driver = {
> +		.name = "ingenic-vpu",
> +#ifdef CONFIG_PM

Not sure why you would want to maintain this conditional, because 
runtime_pm is a core dependency now for your driver to work properly.

regards
Suman

> +		.pm = &ingenic_rproc_pm,
> +#endif
> +		.of_match_table = ingenic_rproc_of_matches,
> +	},
> +};
> +module_platform_driver(ingenic_rproc_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Paul Cercueil <paul@...pouillou.net>");
> +MODULE_DESCRIPTION("Ingenic JZ47xx Remote Processor control driver");
> 

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