Hi, Christophe,
dev_kzalloc really looks better. I will update the patch with the comments
addressed.
Thanks,
Wenhu
From: Christophe Leroy <christophe.le...@c-s.fr> Date: 2020-04-16 19:49:01
To:Wang Wenhu <wenhu.w...@vivo.com>,gre...@linuxfoundation.org,
linux-ker...@vger.kernel.org,o...@buserror.net,linuxppc-dev@lists.ozlabs.org
cc: ker...@vivo.com,Michael Ellerman <m...@ellerman.id.au>
Subject: Re: [PATCH RESEND,v3,4/4] drivers: uio: new driver for
fsl_85xx_cache_sram>
>
>Le 16/04/2020 à 13:16, Wang Wenhu a écrit :
>> 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 <gre...@linuxfoundation.org>
>> Cc: Christophe Leroy <christophe.le...@c-s.fr>
>> Cc: Scott Wood <o...@buserror.net>
>> Cc: Michael Ellerman <m...@ellerman.id.au>
>> Cc: linuxppc-dev@lists.ozlabs.org
>> Signed-off-by: Wang Wenhu <wenhu.w...@vivo.com>
>> ---
>> 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.w...@vivo.com>
>> + * 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.w...@vivo.com>");
>> +MODULE_DESCRIPTION("Freescale MPC85xx Cache-Sram UIO Platform Driver");
>> +MODULE_ALIAS("platform:" DRIVER_NAME);
>> +MODULE_LICENSE("GPL v2");
>>
>
>Christophe
