Re: [RFC PATCH 2/3] remoteproc: imx_rproc: add a NXP/Freescale imx rproc driver

[Oleksij Rempel <ore@pengutronix.de>]

Hi Bjorn,

thank you for review,

On 25.06.2017 22:41, Bjorn Andersson wrote:
> On Wed 14 Jun 13:48 PDT 2017, Oleksij Rempel wrote:
>
>> From: Oleksij Rempel <linux@rempel-privat.de>
>>
>> this driver was tested on NXP imx7d but should work on
>> imx6sx as well.
>> It will upload firmware to OCRAM, which shared memory between
>> Cortex A7 and Cortex M4, then turn M4 on.
>>
>
> This looks very generic, are there any IMX specific parts or is this the
> "default" way of integrating a M4? Could we perhaps come up with a
> common M4-rproc driver?

It is kind of generic. The differences are:
- platform specific clocks/reset/mbox configuration. So, maybe generic 
driver just should provide pre and post start/stop bindings?
- arrays for address translations. Naming seems not to be not really 
important. In my case:
  1) M4 own RAM for best performance. This can be requested immediately 
by rptoc driver.
  2) SRAM. Can be used by other parts of the system. Probably 
application specific, not good for mainline.
  3) limited range of DDR RAM. This should be dynamically allocated on 
request.

For (1) most drivers seem to have nearly identical code which IMO can be 
shared.

> Even though it will be rather short, you need a DT binding document
> defining the compatible and the few properties that you use.
>
>> Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
>> ---
>>  drivers/remoteproc/Kconfig     |   8 ++
>>  drivers/remoteproc/Makefile    |   1 +
>>  drivers/remoteproc/imx_rproc.c | 264 +++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 273 insertions(+)
>>  create mode 100644 drivers/remoteproc/imx_rproc.c
>>
>> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
>> index faad69a1a597..8d33bff4f530 100644
>> --- a/drivers/remoteproc/Kconfig
>> +++ b/drivers/remoteproc/Kconfig
>> @@ -130,6 +130,14 @@ config ST_SLIM_REMOTEPROC
>>  	tristate
>>  	depends on REMOTEPROC
>>
>> +config IMX_REMOTEPROC
>
> Please make an attempt to keep entries in the Kconfig and Makefile
> alphabetically sorted.
>
>> +	tristate "IMX6/7 remoteproc support"
>> +	depends on SOC_IMX6SX || SOC_IMX7D
>> +	depends on REMOTEPROC
>> +	help
>> +	  TODO, write some thing here
>> +	  This can be either built-in or a loadable module.
>> +
>>  endif # REMOTEPROC
>>
>>  endmenu
>> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
>> index ffc5e430df27..d351c25cdb4e 100644
>> --- a/drivers/remoteproc/Makefile
>> +++ b/drivers/remoteproc/Makefile
>> @@ -19,3 +19,4 @@ qcom_wcnss_pil-y			+= qcom_wcnss.o
>>  qcom_wcnss_pil-y			+= qcom_wcnss_iris.o
>>  obj-$(CONFIG_ST_REMOTEPROC)		+= st_remoteproc.o
>>  obj-$(CONFIG_ST_SLIM_REMOTEPROC)	+= st_slim_rproc.o
>> +obj-$(CONFIG_IMX_REMOTEPROC)		+= imx_rproc.o
>> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
>> new file mode 100644
>> index 000000000000..6bef85237a27
>> --- /dev/null
>> +++ b/drivers/remoteproc/imx_rproc.c
>> @@ -0,0 +1,264 @@
>> +/*
>> + * Oleksij Rempel <o.rempel@pengutronix.de>
>> + * 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.
>> + *
>> + * This program is distributed in the hope that 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/err.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/of_device.h>
>> +#include <linux/of_address.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/remoteproc.h>
>> +#include <linux/regmap.h>
>> +#include <linux/mfd/syscon.h>
>> +
>> +#define IMX7D_ENABLE_M4			BIT(3)
>> +#define IMX7D_SW_M4P_RST		BIT(2)
>> +#define IMX7D_SW_M4C_RST		BIT(1)
>> +#define IMX7D_SW_M4C_NON_SCLR_RST	BIT(0)
>> +
>> +#define IMX7D_M4_RST_MASK		0xf
>> +
>> +
>> +#define IMX7D_RPROC_MEM_MAX		2
>> +enum {
>> +	IMX7D_RPROC_IMEM,
>> +	IMX7D_RPROC_DMEM,
>> +};
>> +
>> +static const char *mem_names[IMX7D_RPROC_MEM_MAX] = {
>> +	[IMX7D_RPROC_IMEM]	= "imem",
>> +	[IMX7D_RPROC_DMEM]	= "dmem",
>> +};
>> +
>> +/**
>> + * struct imx_rproc_mem - slim internal memory structure
>> + * @cpu_addr: MPU virtual address of the memory region
>> + * @bus_addr: Bus address used to access the memory region
>> + * @size: Size of the memory region
>> + */
>> +struct imx_rproc_mem {
>> +	void __iomem *cpu_addr;
>> +	phys_addr_t bus_addr;
>> +	size_t size;
>> +};
>> +
>> +struct imx_rproc_dcfg {
>> +	int offset;
>> +};
>
> Unless you foresee this being expanded in the very near future I would
> prefer that you just inline the offset in imx_rproc and put (void*)0xc
> as .data in your of_match (typecast the of_device_get_match_data result
> to unsigned long).
>
>> +
>> +struct imx_rproc {
>> +	struct device			*dev;
>> +	struct regmap			*regmap;
>> +	struct rproc			*rproc;
>> +	const struct imx_rproc_dcfg	*dcfg;
>> +	struct imx_rproc_mem mem[IMX7D_RPROC_MEM_MAX];
>> +	struct clk		*clk;
>> +};
>> +
>> +static const struct imx_rproc_dcfg imx_rproc_cfg_imx7d = {
>> +	.offset = 0xc,
>> +};
>> +
>> +static int imx_rproc_start(struct rproc *rproc)
>> +{
>> +	struct imx_rproc *priv = rproc->priv;
>> +	const struct imx_rproc_dcfg *dcfg = priv->dcfg;
>> +	struct device *dev = priv->dev;
>> +	int ret;
>> +
>> +	ret = clk_enable(priv->clk);
>> +	if (ret) {
>> +		dev_err(&rproc->dev, "Failed to enable clock\n");
>> +		return ret;
>> +	}
>> +
>> +	ret = regmap_update_bits(priv->regmap, dcfg->offset,
>> +				 IMX7D_M4_RST_MASK,
>> +				 IMX7D_SW_M4C_RST | IMX7D_SW_M4P_RST | IMX7D_ENABLE_M4);
>> +	if (ret) {
>> +		dev_err(dev, "Filed to enable M4!\n");
>> +		clk_disable(priv->clk);
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static int imx_rproc_stop(struct rproc *rproc)
>> +{
>> +	struct imx_rproc *priv = rproc->priv;
>> +	const struct imx_rproc_dcfg *dcfg = priv->dcfg;
>> +	struct device *dev = priv->dev;
>> +	int ret;
>> +
>> +	ret = regmap_update_bits(priv->regmap, dcfg->offset,
>> +				 IMX7D_M4_RST_MASK,
>> +				 IMX7D_SW_M4C_NON_SCLR_RST);
>> +	if (ret)
>> +		dev_err(dev, "Filed to stop M4!\n");
>> +
>> +	clk_disable(priv->clk);
>> +
>> +	return ret;
>> +}
>> +
>> +static void *imx_rproc_da_to_va(struct rproc *rproc, u64 da, int len)
>> +{
>> +	struct imx_rproc *priv = rproc->priv;
>> +	void *va = NULL;
>> +	int i;
>> +
>> +	for (i = 0; i < IMX7D_RPROC_MEM_MAX; i++) {
>> +		if (da != priv->mem[i].bus_addr)
>> +			continue;
>> +
>> +		if (len <= priv->mem[i].size) {
>> +			/* __force to make sparse happy with type conversion */
>> +			va = (__force void *)priv->mem[i].cpu_addr;
>> +			break;
>> +		}
>> +	}
>> +
>> +	dev_dbg(&rproc->dev, "da = 0x%llx len = 0x%x va = 0x%p\n", da, len, va);
>> +
>> +	return va;
>> +}
>> +
>> +static const struct rproc_ops imx_rproc_ops = {
>> +	.start		= imx_rproc_start,
>> +	.stop		= imx_rproc_stop,
>> +	.da_to_va       = imx_rproc_da_to_va,
>> +};
>> +
>> +static const struct of_device_id imx_rproc_of_match[] = {
>> +	{ .compatible = "fsl,imx7d-rproc", .data = &imx_rproc_cfg_imx7d },
>
> .data = (void*)0xc
>
>> +	{},
>> +};
>> +MODULE_DEVICE_TABLE(of, imx_rproc_of_match);
>
> By using of_device_get_match_data() you don't need to reference your
> of_device_id table, so please move it down to your definition of
> imx_rproc_driver.
>
> [..]
>> +static int imx_rproc_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct device_node *np = dev->of_node;
>> +	struct imx_rproc *priv;
>> +	struct rproc *rproc;
>> +	struct regmap_config config = { .name = "imx_rproc" };
>> +	const struct imx_rproc_dcfg *dcfg;
>> +	struct regmap *regmap;
>> +	int ret;
>> +
>> +	regmap = syscon_regmap_lookup_by_phandle(np, "syscon");
>> +	if (IS_ERR(regmap)) {
>> +		dev_err(dev, "failed to find syscon\n");
>> +		return PTR_ERR(regmap);
>> +	}
>> +        regmap_attach_dev(dev, regmap, &config);
>
> Indentation...
>
>> +
>> +	/* set some other name then imx */
>> +	rproc = rproc_alloc(dev, "imx_rproc", &imx_rproc_ops, NULL, sizeof(*priv));
>> +	if (!rproc) {
>> +		ret = -ENOMEM;
>> +		goto err;
>> +	}
>> +
>> +	dcfg = of_device_get_match_data(dev);
>
> priv->cfg_offset = (unsigned long)of_device_get_match_data(dev);
>
>> +	if (!dcfg)
>> +		return -EINVAL;
>> +
>> +	priv = rproc->priv;
>> +	priv->rproc = rproc;
>> +	priv->regmap = regmap;
>> +	priv->dcfg = dcfg;
>> +
>> +	dev_set_drvdata(dev, rproc);
>> +
>> +	ret = imx_rproc_addr_init(priv, pdev);
>> +	if (ret) {
>> +		dev_err(dev, "filed on imx_rproc_addr_init\n");
>> +		goto err_put_rproc;
>> +	}
>> +
>> +	priv->clk = devm_clk_get(dev, NULL);
>> +	if (IS_ERR(priv->clk)) {
>> +		dev_err(dev, "Failed to get clock\n");
>
> rproc_free()
>
>> +		return PTR_ERR(priv->clk);
>> +	}
>> +
>> +	ret = rproc_add(rproc);
>> +	if (ret) {
>> +		dev_err(dev, "rproc_add failed\n");
>> +		goto err_put_rproc;
>> +	}
>> +
>> +	ret = clk_prepare(priv->clk);
>
> 1) You're not unpreparing this clock in remove.
>
> 2) Why do you prepare the clock here instead of prepare_enable &
> disable_unprepare it during start/stop?
>
> 3) This is racy as you could have start() being called between
> rproc_add() and clk_prepare() (although highly unlikely...).
>
>> +	if (ret)
>> +		dev_err(dev, "failed to get clock\n");
>
> s/get/prepare/
>
> Regards,
> Bjorn
>