Re:[PATCH v5,4/4] drivers: uio: new driver for fsl_85xx_cache_sram

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>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
>Reviewed-by: Christophe Leroy <christophe.leroy@xxxxxx>
>Signed-off-by: Wang Wenhu <wenhu.wang@xxxxxxxx>

Hi, Christophe,
I labeled you Reviewed comment.

Regards,
Wenhu

>---
>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
> * of_match_table modified to be apart from HW info which belong to
>   the HW level driver fsl_85xx_cache_sram to match
> * Use roundup_pow_of_two for align calc
> * 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
>Changes since v3:
> * Addressed comments from Christophe(use devm_xxx memory alloc interfaces)
>Changes since v4:
> * Use module_param_string for of_match_table, no binding to devicetree
>---
> drivers/uio/Kconfig                   |   9 ++
> drivers/uio/Makefile                  |   1 +
> drivers/uio/uio_fsl_85xx_cache_sram.c | 154 ++++++++++++++++++++++++++
> 3 files changed, 164 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..4db3648629b3
>--- /dev/null
>+++ b/drivers/uio/uio_fsl_85xx_cache_sram.c
>@@ -0,0 +1,154 @@
>+// 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)
>+{
>+	int i;
>+
>+	for (i = 0; i < MAX_UIO_MAPS; i++) {
>+		struct uio_mem *uiomem = &info->mem[i];
>+
>+		if (uiomem->internal_addr) {
>+			mpc85xx_cache_sram_free(uiomem->internal_addr);
>+			memset(uiomem, 0, sizeof(*uiomem));
>+		}
>+	}
>+}
>+
>+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 = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
>+	if (!info)
>+		return -ENOMEM;
>+
>+	/* get optional uio name */
>+	if (of_property_read_string(parent, "uio_name", &dt_name))
>+		dt_name = UIO_NAME;
>+
>+	info->name = devm_kstrdup(&pdev->dev, dt_name, GFP_KERNEL);
>+	if (!info->name)
>+		return -ENOMEM;
>+
>+	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_out;
>+		}
>+
>+		if (mem_size == 0) {
>+			dev_err(&pdev->dev, "error cache-mem-size should not be 0\n");
>+			ret = -EINVAL;
>+			goto err_out;
>+		}
>+
>+		virt = mpc85xx_cache_sram_alloc(mem_size, &phys,
>+						roundup_pow_of_two(mem_size));
>+		if (!virt) {
>+			/* mpc85xx_cache_sram_alloc to define the real cause */
>+			ret = -ENOMEM;
>+			goto err_out;
>+		}
>+
>+		uiomem->memtype = UIO_MEM_PHYS;
>+		uiomem->addr = phys;
>+		uiomem->size = mem_size;
>+		uiomem->name = kstrdup(node->name, GFP_KERNEL);
>+		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 configuration found\n");
>+		return -EINVAL;
>+	}
>+
>+	info->version = UIO_INFO_VER;
>+
>+	/* register uio device */
>+	if (uio_register_device(&pdev->dev, info)) {
>+		dev_err(&pdev->dev, "error uio,cache-sram registration failed\n");
>+		ret = -ENODEV;
>+		goto err_out;
>+	}
>+
>+	platform_set_drvdata(pdev, info);
>+
>+	return 0;
>+err_out:
>+	uio_info_free_internal(info);
>+	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);
>+
>+	return 0;
>+}
>+
>+#ifdef CONFIG_OF
>+static struct of_device_id uio_fsl_85xx_cache_sram_of_match[] = {
>+	{ /* This is filled with module_parm */ },
>+	{ /* Sentinel */ },
>+};
>+MODULE_DEVICE_TABLE(of, uio_fsl_85xx_cache_sram_of_match);
>+
>+module_param_string(of_id, uio_fsl_85xx_cache_sram_of_match[0].compatible,
>+		    sizeof(uio_fsl_85xx_cache_sram_of_match[0].compatible), 0);
>+MODULE_PARM_DESC(of_id, "platform device id to be handled by cache-sram-uio");
>+#endif
>+
>+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,
>+		.of_match_table	= of_match_ptr(uio_fsl_85xx_cache_sram_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");
>-- 
>2.17.1
>