Re:Re: [PATCH RESEND,v3,4/4] drivers: uio: new driver for fsl_85xx_cache_sram

[çæè]

Hi, Christophe,
dev_kzalloc really looks better. I will update the patch with the comments addressed.

Thanks,
Wenhu

From: Christophe Leroy <christophe.leroy@xxxxxx> Date: 2020-04-16 19:49:01
To:Wang Wenhu <wenhu.wang@xxxxxxxx>,gregkh@xxxxxxxxxxxxxxxxxxx,
linux-kernel@xxxxxxxxxxxxxxx,oss@xxxxxxxxxxxx,linuxppc-dev@xxxxxxxxxxxxxxxx
 cc: kernel@xxxxxxxx,Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Subject: Re: [PATCH RESEND,v3,4/4] drivers: uio: new driver for fsl_85xx_cache_sram>
>
>Le 16/04/2020 Ã 13:16, Wang Wenhu a ÃcritÂ:
>> A driver for freescale 85xx platforms to access the Cache-Sram form
>> user level. This is extremely helpful for some user-space applications
>> that require high performance memory accesses.
>> 
>> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>> Cc: Christophe Leroy <christophe.leroy@xxxxxx>
>> Cc: Scott Wood <oss@xxxxxxxxxxxx>
>> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
>> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
>> Signed-off-by: Wang Wenhu <wenhu.wang@xxxxxxxx>
>> ---
>> Changes since v1:
>>   * Addressed comments from Greg K-H
>>   * Moved kfree(info->name) into uio_info_free_internal()
>> Changes since v2:
>>   * Addressed comments from Greg, Scott and Christophe
>>   * Use "uiomem->internal_addr" as if condition for sram memory free,
>>     and memset the uiomem entry
>>   * Modified of_match_table make the driver apart from Cache-Sram HW info
>>     which belong to the HW level driver fsl_85xx_cache_sram to match
>>   * Use roundup_pow_of_two for align calculation
>>   * Remove useless clear block of uiomem entries.
>>   * Use UIO_INFO_VER micro for info->version, and define it as
>>     "devicetree,pseudo", meaning this is pseudo device and probed from
>>     device tree configuration
>>   * Select FSL_85XX_CACHE_SRAM rather than depends on it
>> ---
>>   drivers/uio/Kconfig                   |   9 ++
>>   drivers/uio/Makefile                  |   1 +
>>   drivers/uio/uio_fsl_85xx_cache_sram.c | 158 ++++++++++++++++++++++++++
>>   3 files changed, 168 insertions(+)
>>   create mode 100644 drivers/uio/uio_fsl_85xx_cache_sram.c
>> 
>> diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
>> index 202ee81cfc2b..9c3b47461b71 100644
>> --- a/drivers/uio/Kconfig
>> +++ b/drivers/uio/Kconfig
>> @@ -105,6 +105,15 @@ config UIO_NETX
>>   	  To compile this driver as a module, choose M here; the module
>>   	  will be called uio_netx.
>>   
>> +config UIO_FSL_85XX_CACHE_SRAM
>> +	tristate "Freescale 85xx Cache-Sram driver"
>> +	depends on FSL_SOC_BOOKE && PPC32
>> +	select FSL_85XX_CACHE_SRAM
>> +	help
>> +	  Generic driver for accessing the Cache-Sram form user level. This
>> +	  is extremely helpful for some user-space applications that require
>> +	  high performance memory accesses.
>> +
>>   config UIO_FSL_ELBC_GPCM
>>   	tristate "eLBC/GPCM driver"
>>   	depends on FSL_LBC
>> diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile
>> index c285dd2a4539..be2056cffc21 100644
>> --- a/drivers/uio/Makefile
>> +++ b/drivers/uio/Makefile
>> @@ -10,4 +10,5 @@ obj-$(CONFIG_UIO_NETX)	+= uio_netx.o
>>   obj-$(CONFIG_UIO_PRUSS)         += uio_pruss.o
>>   obj-$(CONFIG_UIO_MF624)         += uio_mf624.o
>>   obj-$(CONFIG_UIO_FSL_ELBC_GPCM)	+= uio_fsl_elbc_gpcm.o
>> +obj-$(CONFIG_UIO_FSL_85XX_CACHE_SRAM)	+= uio_fsl_85xx_cache_sram.o
>>   obj-$(CONFIG_UIO_HV_GENERIC)	+= uio_hv_generic.o
>> diff --git a/drivers/uio/uio_fsl_85xx_cache_sram.c b/drivers/uio/uio_fsl_85xx_cache_sram.c
>> new file mode 100644
>> index 000000000000..8701df695307
>> --- /dev/null
>> +++ b/drivers/uio/uio_fsl_85xx_cache_sram.c
>> @@ -0,0 +1,158 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (C) 2020 Vivo Communication Technology Co. Ltd.
>> + * Copyright (C) 2020 Wang Wenhu <wenhu.wang@xxxxxxxx>
>> + * All rights reserved.
>> + */
>> +
>> +#include <linux/platform_device.h>
>> +#include <linux/uio_driver.h>
>> +#include <linux/stringify.h>
>> +#include <linux/module.h>
>> +#include <linux/kernel.h>
>> +#include <asm/fsl_85xx_cache_sram.h>
>> +
>> +#define DRIVER_NAME	"uio_fsl_85xx_cache_sram"
>> +#define UIO_INFO_VER	"devicetree,pseudo"
>> +#define UIO_NAME	"uio_cache_sram"
>> +
>> +static void uio_info_free_internal(struct uio_info *info)
>> +{
>> +	struct uio_mem *uiomem = info->mem;
>> +
>> +	while (uiomem < &info->mem[MAX_UIO_MAPS]) {
>
>As suggested by Scott, maybe it would be better to use a loop with an 
>index, something like
>
>	for (i = 0; i < MAX_UIO_MAPS; i++, uiomem++) {
>		struct uio_mem *uiomem = info->mem[i];
>
>> +		if (uiomem->internal_addr) {
>> +			mpc85xx_cache_sram_free(uiomem->internal_addr);
>> +			kfree(uiomem->name);
>
>Unneeded when using devm_kstrdup(), see in the probe function.
>
>> +			memset(uiomem, 0, sizeof(*uiomem));
>> +		}
>> +		uiomem++;
>> +	}
>> +
>> +	kfree(info->name);
>
>That's a bit unbalanced. This function is handy for the things allocated 
>inside the loop, but for the info->name allocated outside the loop, it 
>should be released outside this function.
>
>At the end if you use devm_kstrdup(), it will void anyway.
>
>> +}
>> +
>> +static int uio_fsl_85xx_cache_sram_probe(struct platform_device *pdev)
>> +{
>> +	struct device_node *parent = pdev->dev.of_node;
>> +	struct device_node *node = NULL;
>> +	struct uio_info *info;
>> +	struct uio_mem *uiomem;
>> +	const char *dt_name;
>> +	u32 mem_size;
>> +	int ret;
>> +
>> +	/* alloc uio_info for one device */
>> +	info = kzalloc(sizeof(*info), GFP_KERNEL);
>
>Maybe use devm_kzalloc(). That way, it will be automatically freed when 
>the driver is released, both a normal release and on probe failure.
>
>> +	if (!info)
>> +		return -ENOMEM;
>> +
>> +	/* get optional uio name */
>> +	if (of_property_read_string(parent, "uio_name", &dt_name))
>> +		dt_name = UIO_NAME;
>> +
>> +	info->name = kstrdup(dt_name, GFP_KERNEL);
>
>Can use devm_kstrdup()
>
>> +	if (!info->name) {
>> +		ret = -ENOMEM;
>
>If using devm_kzalloc(), you can then directly do return -ENOMEM, and 
>the release will be automatic.
>
>> +		goto err_info_free;
>> +	}
>> +
>> +	uiomem = info->mem;
>> +	for_each_child_of_node(parent, node) {
>> +		void *virt;
>> +		phys_addr_t phys;
>> +
>> +		ret = of_property_read_u32(node, "cache-mem-size", &mem_size);
>> +		if (ret) {
>> +			ret = -EINVAL;
>> +			goto err_info_free_internal;
>> +		}
>> +
>> +		if (mem_size == 0) {
>> +			dev_err(&pdev->dev, "cache-mem-size should not be 0\n");
>> +			ret = -EINVAL;
>> +			goto err_info_free_internal;
>> +		}
>> +
>> +		virt = mpc85xx_cache_sram_alloc(mem_size,
>> +						&phys,
>
>I think &phys can fit on first line.
>
>> +						roundup_pow_of_two(mem_size));
>> +		if (!virt) {
>> +			/* mpc85xx_cache_sram_alloc to define the real cause */
>> +			ret = -ENOMEM;
>> +			goto err_info_free_internal;
>> +		}
>> +
>> +		uiomem->memtype = UIO_MEM_PHYS;
>> +		uiomem->addr = phys;
>> +		uiomem->size = mem_size;
>> +		uiomem->name = kstrdup(node->name, GFP_KERNEL);;
>
>Use devm_kstrdup()
>
>> +		uiomem->internal_addr = virt;
>> +		uiomem++;
>> +
>> +		if (uiomem >= &info->mem[MAX_UIO_MAPS]) {
>> +			dev_warn(&pdev->dev, "more than %d uio-maps for device.\n",
>> +				 MAX_UIO_MAPS);
>> +			break;
>> +		}
>> +	}
>> +
>> +	if (uiomem == info->mem) {
>> +		dev_err(&pdev->dev, "error no valid uio-map configured\n");
>> +		ret = -EINVAL;
>> +		goto err_info_free_internal;
>
>Is there anything to free up if nothing has been allocated ?
>
>> +	}
>> +
>> +	info->version = UIO_INFO_VER;
>> +
>> +	/* register uio device */
>> +	if (uio_register_device(&pdev->dev, info)) {
>> +		dev_err(&pdev->dev, "uio registration failed\n");
>> +		ret = -ENODEV;
>> +		goto err_info_free_internal;
>> +	}
>> +
>> +	platform_set_drvdata(pdev, info);
>> +
>> +	return 0;
>> +err_info_free_internal:
>> +	uio_info_free_internal(info);
>> +err_info_free:
>> +	kfree(info);
>
>Shouldn't be needed when using devm_kzalloc().
>
>> +	return ret;
>> +}
>> +
>> +static int uio_fsl_85xx_cache_sram_remove(struct platform_device *pdev)
>> +{
>> +	struct uio_info *info = platform_get_drvdata(pdev);
>> +
>> +	uio_unregister_device(info);
>> +
>> +	uio_info_free_internal(info);
>> +
>> +	kfree(info);
>
>Not needed when using dev_kzalloc()
>
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id uio_mpc85xx_l2ctlr_of_match[] = {
>> +	{	.compatible = "uio,mpc85xx-cache-sram",	},
>> +	{},
>> +};
>> +
>> +static struct platform_driver uio_fsl_85xx_cache_sram = {
>> +	.probe = uio_fsl_85xx_cache_sram_probe,
>> +	.remove = uio_fsl_85xx_cache_sram_remove,
>> +	.driver = {
>> +		.name = DRIVER_NAME,
>> +		.owner = THIS_MODULE,
>> +		.of_match_table	= uio_mpc85xx_l2ctlr_of_match,
>> +	},
>> +};
>> +
>> +module_platform_driver(uio_fsl_85xx_cache_sram);
>> +
>> +MODULE_AUTHOR("Wang Wenhu <wenhu.wang@xxxxxxxx>");
>> +MODULE_DESCRIPTION("Freescale MPC85xx Cache-Sram UIO Platform Driver");
>> +MODULE_ALIAS("platform:" DRIVER_NAME);
>> +MODULE_LICENSE("GPL v2");
>> 
>
>Christophe