Message-ID: <55E8A517.6040807@ti.com>
Date:	Thu, 3 Sep 2015 14:52:55 -0500
From:	Suman Anna <s-anna@...com>
To:	Lee Jones <lee.jones@...aro.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:	"kernel@...inux.com" <kernel@...inux.com>,
	"ohad@...ery.com" <ohad@...ery.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"Nathan_Lynch@...tor.com" <Nathan_Lynch@...tor.com>,
	"f.fainelli@...il.com" <f.fainelli@...il.com>,
	Ludovic Barre <ludovic.barre@...com>
Subject: Re: [PATCH v3 3/6] remoteproc: Supply controller driver for ST's
 Remote Processors

Hi Lee,

On 09/02/2015 10:38 AM, Lee Jones wrote:
> Signed-off-by: Ludovic Barre <ludovic.barre@...com>
> Signed-off-by: Lee Jones <lee.jones@...aro.org>
> ---
>  drivers/remoteproc/Kconfig         |   9 ++
>  drivers/remoteproc/Makefile        |   1 +
>  drivers/remoteproc/st_remoteproc.c | 307 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 317 insertions(+)
>  create mode 100644 drivers/remoteproc/st_remoteproc.c
> 
> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> index 28c711f..72e97d7 100644
> --- a/drivers/remoteproc/Kconfig
> +++ b/drivers/remoteproc/Kconfig
> @@ -77,4 +77,13 @@ config DA8XX_REMOTEPROC
>  	  It's safe to say n here if you're not interested in multimedia
>  	  offloading.
>  
> +config ST_REMOTEPROC
> +	tristate "ST remoteproc support"
> +	depends on ARCH_STI
> +	select REMOTEPROC
> +	help
> +	  Say y here to support ST's adjunct processors via the remote
> +	  processor framework.
> +	  This can be either built-in or a loadable module.
> +
>  endmenu
> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
> index 81b04d1..279cb2e 100644
> --- a/drivers/remoteproc/Makefile
> +++ b/drivers/remoteproc/Makefile
> @@ -11,3 +11,4 @@ obj-$(CONFIG_OMAP_REMOTEPROC)		+= omap_remoteproc.o
>  obj-$(CONFIG_STE_MODEM_RPROC)	 	+= ste_modem_rproc.o
>  obj-$(CONFIG_WKUP_M3_RPROC)		+= wkup_m3_rproc.o
>  obj-$(CONFIG_DA8XX_REMOTEPROC)		+= da8xx_remoteproc.o
> +obj-$(CONFIG_ST_REMOTEPROC)		+= st_remoteproc.o
> diff --git a/drivers/remoteproc/st_remoteproc.c b/drivers/remoteproc/st_remoteproc.c
> new file mode 100644
> index 0000000..24ae6d3
> --- /dev/null
> +++ b/drivers/remoteproc/st_remoteproc.c
> @@ -0,0 +1,307 @@
> +/*
> + * ST's Remote Processor Control Driver
> + *
> + * Copyright (C) 2015 STMicroelectronics - All Rights Reserved
> + *
> + * Author: Ludovic Barre <ludovic.barre@...com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/remoteproc.h>
> +#include <linux/reset.h>
> +
> +struct st_rproc_config {
> +	bool			sw_reset;
> +	bool			pwr_reset;
> +	u32			bootaddr_mask;
> +};
> +
> +struct st_rproc {
> +	struct st_rproc_config	*config;
> +	struct reset_control	*sw_reset;
> +	struct reset_control	*pwr_reset;
> +	struct clk		*clk;
> +	u32			clk_rate;
> +	struct regmap		*boot_base;
> +	u32			boot_offset;
> +};
> +
> +static int st_rproc_stop(struct rproc *rproc)
> +{
> +	struct st_rproc *ddata = rproc->priv;
> +	int sw_err = 0, pwr_err = 0;
> +
> +	if (ddata->config->sw_reset) {
> +		sw_err = reset_control_assert(ddata->sw_reset);
> +		if (sw_err)
> +			dev_err(&rproc->dev, "Failed to assert S/W Reset\n");
> +	}
> +
> +	if (ddata->config->pwr_reset) {
> +		pwr_err = reset_control_assert(ddata->pwr_reset);
> +		if (pwr_err)
> +			dev_err(&rproc->dev, "Failed to assert Power Reset\n");
> +	}
> +
> +	clk_disable(ddata->clk);
> +
> +	return sw_err ?: pwr_err;
> +}

nit, can you please move st_rproc_stop function after st_rproc_start,
same order as in fw_ops, for better flow.

> +
> +static int st_rproc_start(struct rproc *rproc)
> +{
> +	struct st_rproc *ddata = rproc->priv;
> +	int err;
> +
> +	regmap_update_bits(ddata->boot_base, ddata->boot_offset,
> +			   ddata->config->bootaddr_mask, rproc->bootaddr);
> +
> +	err = clk_enable(ddata->clk);
> +	if (err) {
> +		dev_err(&rproc->dev, "Failed to enable clock\n");
> +		return err;
> +	}
> +
> +	if (ddata->config->sw_reset) {
> +		err = reset_control_deassert(ddata->sw_reset);
> +		if (err) {
> +			dev_err(&rproc->dev, "Failed to deassert S/W Reset\n");
> +			goto sw_reset_fail;
> +		}
> +	}
> +
> +	if (ddata->config->pwr_reset) {
> +		err = reset_control_deassert(ddata->pwr_reset);
> +		if (err) {
> +			dev_err(&rproc->dev, "Failed to deassert Power Reset\n");
> +			goto pwr_reset_fail;
> +		}
> +	}
> +
> +	dev_info(&rproc->dev, "Started from 0x%x\n", rproc->bootaddr);
> +
> +	return 0;
> +
> +
> +pwr_reset_fail:
> +	reset_control_assert(ddata->sw_reset);

Should this be under a check for (ddata->config->sw_reset). It is not
clear from code whether the sw_reset and pwr_reset are exclusive of each
of other or have both.

> +sw_reset_fail:
> +	clk_disable(ddata->clk);
> +
> +	return err;
> +}
> +
> +static struct rproc_ops st_rproc_ops = {
> +	.start		= st_rproc_start,
> +	.stop		= st_rproc_stop,
> +};
> +
> +/*
> + * Fetch state of the processor: 0 is off, 1 is on.
> + */
> +static int st_rproc_state(struct platform_device *pdev)
> +{
> +	struct rproc *rproc = platform_get_drvdata(pdev);
> +	struct st_rproc *ddata = rproc->priv;
> +	int reset_sw = 0, reset_pwr = 0;
> +
> +	if (ddata->config->sw_reset)
> +		reset_sw = reset_control_status(ddata->sw_reset);
> +
> +	if (ddata->config->pwr_reset)
> +		reset_pwr = reset_control_status(ddata->pwr_reset);
> +
> +	if (reset_sw < 0 || reset_pwr < 0)
> +		return -EINVAL;
> +
> +	return !reset_sw && !reset_pwr;
> +}
> +
> +static const struct st_rproc_config st40_rproc_cfg = {
> +	.sw_reset = true,
> +	.pwr_reset = true,
> +	.bootaddr_mask = GENMASK(28, 1),
> +};
> +
> +static const struct st_rproc_config st231_rproc_cfg = {
> +	.sw_reset = true,
> +	.pwr_reset = false,
> +	.bootaddr_mask = GENMASK(31, 6),
> +};
> +
> +static const struct of_device_id st_rproc_match[] = {
> +	{ .compatible = "st,st40-rproc", .data = &st40_rproc_cfg },
> +	{ .compatible = "st,st231-rproc", .data = &st231_rproc_cfg },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, st_rproc_match);
> +
> +static int st_rproc_parse_dt(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct rproc *rproc = platform_get_drvdata(pdev);
> +	struct st_rproc *ddata = rproc->priv;
> +	struct device_node *np = dev->of_node;
> +	struct resource	*mem;
> +	int err;
> +
> +	if (ddata->config->sw_reset) {
> +		ddata->sw_reset = devm_reset_control_get(dev, "sw_reset");
> +		if (IS_ERR(ddata->sw_reset)) {
> +			dev_err(dev, "Failed to get S/W Reset\n");
> +			return PTR_ERR(ddata->sw_reset);
> +		}
> +	}
> +
> +	if (ddata->config->pwr_reset) {
> +		ddata->pwr_reset = devm_reset_control_get(dev, "pwr_reset");
> +		if (IS_ERR(ddata->pwr_reset)) {
> +			dev_err(dev, "Failed to get Power Reset\n");
> +			return PTR_ERR(ddata->pwr_reset);
> +		}
> +	}
> +
> +	ddata->clk = devm_clk_get(dev, NULL);
> +	if (IS_ERR(ddata->clk)) {
> +		dev_err(dev, "Failed to get clock\n");
> +		return PTR_ERR(ddata->clk);
> +	}
> +
> +	err = of_property_read_u32(np, "clock-frequency", &ddata->clk_rate);
> +	if (err) {
> +		dev_err(dev, "failed to get clock frequency\n");
> +		return err;
> +	}
> +
> +	ddata->boot_base = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
> +	if (!ddata->boot_base) {
> +		dev_err(dev, "Boot base not found\n");
> +		return -EINVAL;
> +	}
> +
> +	err = of_property_read_u32_index(np, "st,syscfg", 1,
> +					 &ddata->boot_offset);
> +	if (err) {
> +		dev_err(dev, "Boot offset not found\n");
> +		return -EINVAL;
> +	}
> +
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!mem) {
> +		dev_err(dev, "no rproc memory definition\n");
> +		return -ENXIO;
> +	}
> +
> +	if (!devm_request_mem_region(dev, mem->start,
> +				     resource_size(mem), pdev->name)) {
> +		dev_err(dev, "failed to get memory region resource\n");
> +		return -EBUSY;
> +	}
> +	err = dmam_declare_coherent_memory(dev, mem->start, mem->start,
> +					  resource_size(mem),
> +					  DMA_MEMORY_MAP |
> +					  DMA_MEMORY_EXCLUSIVE);
> +	if (err < 0) {
> +		dev_err(dev, "cannot declare coherent memory: %d\n", err);
> +		return -ENXIO;
> +	}

What kind of memory will this be? If this a carveout memory being
set-aside from DDR, you may want to use a reserved-memory node entry,
with a "memory-region" property added to the rproc device node and use
of_reserved_mem_device_init() and of_reserved_mem_device_release() API,
following the standard semantics of reserved-memory as in
Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt.

Obviously that will need a change in the binding as well.

> +
> +	err = clk_prepare(ddata->clk);
> +	if (err)
> +		dev_err(dev, "failed to get clock\n");
> +
> +	return err;
> +}
> +
> +static int st_rproc_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	const struct of_device_id *match;
> +	struct st_rproc *ddata;
> +	struct device_node *np = dev->of_node;
> +	struct rproc *rproc;
> +	int enabled;
> +	int ret;
> +
> +	match = of_match_device((st_rproc_match), dev);
> +	if (!match || !match->data) {
> +		dev_err(dev, "No device match found\n");
> +		return -ENODEV;
> +	}
> +
> +	rproc = rproc_alloc(dev, np->name, &st_rproc_ops, NULL, sizeof(*ddata));
> +	if (!rproc)
> +		return -ENOMEM;
> +
> +	ddata = rproc->priv;
> +	ddata->config = (struct st_rproc_config *)match->data;

I believe Ohad's preference is to explicitly set rproc->has_iommu to false.

> +
> +	platform_set_drvdata(pdev, rproc);
> +
> +	ret = st_rproc_parse_dt(pdev);
> +	if (ret)
> +		goto free_rproc;
> +
> +	enabled = st_rproc_state(pdev);
> +	if (enabled < 0)
> +		goto free_rproc;
> +
> +	if (enabled) {
> +		atomic_inc(&rproc->power);
> +		rproc->state = RPROC_RUNNING;

I am curious about this change, who are you expecting to have booted the
processor before the driver is probed?

> +	} else {
> +		clk_set_rate(ddata->clk, ddata->clk_rate);
> +	}
> +
> +	ret = rproc_add(rproc);
> +	if (ret)
> +		goto free_rproc;
> +
> +	return 0;
> +
> +free_rproc:
> +	rproc_put(rproc);
> +	return ret;
> +}
> +
> +static int st_rproc_remove(struct platform_device *pdev)
> +{
> +	struct rproc *rproc = platform_get_drvdata(pdev);
> +	struct st_rproc *ddata = rproc->priv;
> +
> +	rproc_del(rproc);
> +
> +	clk_disable_unprepare(ddata->clk);
> +
> +	rproc_put(rproc);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver st_rproc_driver = {
> +	.probe = st_rproc_probe,
> +	.remove = st_rproc_remove,
> +	.driver = {
> +		.name = "st-rproc",
> +		.of_match_table = of_match_ptr(st_rproc_match),
> +	},
> +};
> +module_platform_driver(st_rproc_driver);
> +
> +MODULE_DESCRIPTION("ST Remote Processor Control Driver");
> +MODULE_AUTHOR("Ludovic Barre <ludovic.barre@...com>");
> +MODULE_LICENSE("GPL v2");
> 

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