Re: [PATCH 5/5] drivers: uio: new driver for fsl_85xx_cache_sram>On Wed, Apr 15, 2020 at 05:33:46AM -0700, Wang Wenhu wrote:

Hi, Greg k-h!
Thank you for you fast reply. All the comments will
be addressed with v2 soon. Detailed explanations are
just below specific comment.

quoted

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@linuxfoundation.org>
Cc: Christophe Leroy <redacted>
Cc: Scott Wood <oss@buserror.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Wang Wenhu <redacted>
---
 drivers/uio/Kconfig                   |   8 ++
 drivers/uio/Makefile                  |   1 +
 drivers/uio/uio_fsl_85xx_cache_sram.c | 195 ++++++++++++++++++++++++++
 3 files changed, 204 insertions(+)
 create mode 100644 drivers/uio/uio_fsl_85xx_cache_sram.c

diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
index 202ee81cfc2b..afd38ec13de0 100644
--- a/drivers/uio/Kconfig
+++ b/drivers/uio/Kconfig

@@ -105,6 +105,14 @@ 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_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..e11202dd5b93
--- /dev/null
+++ b/drivers/uio/uio_fsl_85xx_cache_sram.c

@@ -0,0 +1,195 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Vivo Communication Technology Co. Ltd.
+ * Copyright (C) 2020 Wang Wenhu <wenhu.wang@vivo.com>
+ * All rights reserved.
+ *
+ * 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.

Nit, you don't need this sentance anymore now that you have the SPDX
line above

Got, I will delete it with v2.

quoted

+ */
+
+#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_VERSION	"0.1.0"

Don't do DRIVER_VERSIONs, they never work once the code is in the kernel
tree.

quoted

+#define DRIVER_NAME	"uio_fsl_85xx_cache_sram"

KBUILD_MODNAME?

Yes, and sorry for that I did not get what should have been done?

quoted

+#define UIO_NAME	"uio_cache_sram"
+
+static const struct of_device_id uio_mpc85xx_l2ctlr_of_match[] = {
+	{	.compatible = "uio,fsl,p2020-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,p2010-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,p1020-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,p1011-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,p1013-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,p1022-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,mpc8548-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,mpc8544-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,mpc8572-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,mpc8536-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,p1021-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,p1012-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,p1025-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,p1016-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,p1024-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,p1015-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,p1010-l2-cache-controller",	},
+	{	.compatible = "uio,fsl,bsc9131-l2-cache-controller",	},
+	{},
+};
+
+static void uio_info_free_internal(struct uio_info *info)
+{
+	struct uio_mem *uiomem = &info->mem[0];
+
+	while (uiomem < &info->mem[MAX_UIO_MAPS]) {
+		if (uiomem->size) {
+			mpc85xx_cache_sram_free(uiomem->internal_addr);
+			kfree(uiomem->name);
+		}
+		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;
+	u32 align;
+	void *virt;
+	phys_addr_t phys;
+	int ret = -ENODEV;
+
+	/* alloc uio_info for one device */
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info) {
+		dev_err(&pdev->dev, "kzalloc uio_info failed\n");

kzalloc already says this.

Surely, I will delete with v2.

quoted

+		ret = -ENOMEM;
+		goto err_out;
+	}
+
+	/* 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);
+	if (!info->name) {
+		dev_err(&pdev->dev, "error kstrdup uio_name\n");

kstrdup should have given you an error string already, right?

Surely, I will delete with v2.

quoted

+		ret = -ENOMEM;
+		goto err_info_free;
+	}
+
+	uiomem = &info->mem[0];
+	for_each_child_of_node(parent, node) {
+		if (!node) {
+			dev_err(&pdev->dev, "device's OF-node is NULL\n");

How can this happen?

My fault, this would never happen. I will address it in v2.

quoted

+			continue;

Why not error out?

quoted

+		}
+
+		ret = of_property_read_u32(node, "cache-mem-size", &mem_size);
+		if (ret) {
+			dev_err(&pdev->dev, "missing cache-mem-size value\n");

You don't exit?

quoted

+			continue;
+		}
+
+		if (mem_size == 0) {
+			dev_err(&pdev->dev, "cache-mem-size should not be 0\n");

Again, you don't exit?

quoted

+			continue;
+		}
+
+		align = 2;
+		while (align < mem_size)
+			align *= 2;
+		virt = mpc85xx_cache_sram_alloc(mem_size, &phys, align);
+		if (!virt) {
+			dev_err(&pdev->dev, "allocate 0x%x cache-mem failed\n", mem_size);

You don't exit?

Actual all these situations should error out. For the continue branches,
we got a situation that we accept all the possibly correct child node
configurations, and it works. But it is not the common circumstance.
I have tested all these situations and I will change all these to error
out processes with v2.

quoted

+			continue;
+		}
+
+		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, "device has more than "
+				 __stringify(MAX_UIO_MAPS)
+				 " I/O memory resources.\n");

What can someone do with that?

Surely it should be more friendly. I will address it with v2.

thanks,

greg k-h