Re: [PATCH v2 1/2] staging: ion: Add generic ion-physmem driver

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Sat, Apr 11, 2015 at 12:12:59AM +0300, Andrew Andrianov wrote:
> Signed-off-by: Andrew Andrianov <andrew@ncrmnt.org>

You need something here in the changelog entry, you just added a whole
new driver.  Please give some information as to what it does, why we
need it, and how to use it.

> ---
>  drivers/staging/android/ion/Kconfig       |    7 +
>  drivers/staging/android/ion/Makefile      |    5 +-
>  drivers/staging/android/ion/ion_physmem.c |  226 +++++++++++++++++++++++++++++
>  include/dt-bindings/ion,physmem.h         |   17 +++
>  4 files changed, 253 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/staging/android/ion/ion_physmem.c
>  create mode 100644 include/dt-bindings/ion,physmem.h
> 
> diff --git a/drivers/staging/android/ion/Kconfig b/drivers/staging/android/ion/Kconfig
> index 3452346..c558cf8 100644
> --- a/drivers/staging/android/ion/Kconfig
> +++ b/drivers/staging/android/ion/Kconfig
> @@ -33,3 +33,10 @@ config ION_TEGRA
>  	help
>  	  Choose this option if you wish to use ion on an nVidia Tegra.
>  
> +config ION_PHYSMEM
> +	bool "Generic PhysMem ION driver"
> +	depends on ION
> +	help
> +	  Provides a generic ION driver that registers the
> +	  /dev/ion device with heaps from devicetree entries.
> +	  This heaps are made of chunks of physical memory
> diff --git a/drivers/staging/android/ion/Makefile b/drivers/staging/android/ion/Makefile
> index b56fd2b..ac9856d 100644
> --- a/drivers/staging/android/ion/Makefile
> +++ b/drivers/staging/android/ion/Makefile
> @@ -5,6 +5,7 @@ ifdef CONFIG_COMPAT
>  obj-$(CONFIG_ION) += compat_ion.o
>  endif
>  
> -obj-$(CONFIG_ION_DUMMY) += ion_dummy_driver.o
> -obj-$(CONFIG_ION_TEGRA) += tegra/
> +obj-$(CONFIG_ION_DUMMY)   += ion_dummy_driver.o
> +obj-$(CONFIG_ION_PHYSMEM) += ion_physmem.o
> +obj-$(CONFIG_ION_TEGRA)   += tegra/
>  
> diff --git a/drivers/staging/android/ion/ion_physmem.c b/drivers/staging/android/ion/ion_physmem.c
> new file mode 100644
> index 0000000..5ebcd85
> --- /dev/null
> +++ b/drivers/staging/android/ion/ion_physmem.c
> @@ -0,0 +1,226 @@
> +/*
> + * Copyright (C) 2015 RC Module
> + * Andrew Andrianov <andrew@ncrmnt.org>
> + *
> + * 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.
> + *
> + * Generic devicetree physmem driver for ION Memory Manager
> + *
> + */
> +
> +#include <linux/init.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/of_address.h>
> +#include <linux/clk.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/io.h>
> +#include "ion.h"
> +#include "ion_priv.h"
> +
> +#define DRVNAME "ion-physmem"
> +
> +static struct ion_device *idev;
> +static int num_heaps_registered;
> +static uint32_t claimed_heap_ids;
> +
> +static const struct of_device_id of_match_table[] = {
> +	{ .compatible = "ion,physmem", },
> +	{ /* end of list */ }
> +};
> +
> +struct physmem_ion_dev {
> +	struct ion_platform_heap  data;
> +	struct ion_heap          *heap;
> +	int                       need_free_coherent;
> +	void                     *freepage_ptr;
> +	struct clk               *clk;
> +};
> +
> +static int ion_physmem_probe(struct platform_device *pdev)
> +{
> +	int ret;
> +	u32 ion_heap_id, ion_heap_align, ion_heap_type;
> +	ion_phys_addr_t addr;
> +	size_t size = 0;
> +	const char *ion_heap_name = NULL;
> +	struct resource *res;
> +	struct physmem_ion_dev *ipdev;
> +
> +	/*
> +	   Looks like we can only have one ION device in our system.
> +	   Therefore we call ion_device_create on first probe and only
> +	   add heaps to it on subsequent probe calls.
> +	   FixMe:
> +	   1. Do we need to hold a spinlock here?
> +	   2. Can several probes race here on SMP?
> +	*/
> +
> +	if (!idev) {
> +		idev = ion_device_create(NULL);
> +		dev_info(&pdev->dev, "ION PhysMem Driver. (c) RC Module 2015\n");
> +		if (!idev)
> +			return -ENOMEM;
> +	}
> +
> +	ipdev = kzalloc(sizeof(struct physmem_ion_dev), GFP_KERNEL);
> +	if (!ipdev)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, ipdev);
> +
> +	/* Read out name first for the sake of sane error-reporting */
> +	ret =  of_property_read_string(pdev->dev.of_node, "ion-heap-name",
> +				       &ion_heap_name);
> +	if (ret != 0)
> +		goto errfreeipdev;
> +
> +	ret =  of_property_read_u32(pdev->dev.of_node, "ion-heap-id",
> +				    &ion_heap_id);
> +	if (ret != 0)
> +		goto errfreeipdev;
> +
> +	/* Check id to be sane first */
> +	if ((ion_heap_id < 0) || (ion_heap_id >= ION_NUM_HEAP_IDS)) {
> +		dev_err(&pdev->dev, "bad heap id specified: %d\n",
> +			ion_heap_id);
> +		goto errfreeipdev;
> +	}
> +
> +	if ((1 << ion_heap_id) & claimed_heap_ids) {
> +		dev_err(&pdev->dev, "heap id %d is already claimed\n",
> +			ion_heap_id);
> +		goto errfreeipdev;
> +	}
> +
> +	ret =  of_property_read_u32(pdev->dev.of_node, "ion-heap-type",
> +				    &ion_heap_type);
> +	if (ret != 0)
> +		goto errfreeipdev;
> +
> +	ret =  of_property_read_u32(pdev->dev.of_node, "ion-heap-align",
> +				    &ion_heap_align);
> +	if (ret != 0)
> +		goto errfreeipdev;
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "memory");
> +	/* Not always needed, throw no error if missing */
> +	if (res) {
> +		/* Fill in some defaults */
> +		addr = res->start;
> +		size = resource_size(res);
> +	}
> +
> +	switch (ion_heap_type) {
> +	case ION_HEAP_TYPE_DMA:
> +		if (res) {
> +			ret = dma_declare_coherent_memory(&pdev->dev,
> +							  res->start,
> +							  res->start,
> +							  resource_size(res),
> +							  DMA_MEMORY_MAP |
> +							  DMA_MEMORY_EXCLUSIVE);
> +			if (ret == 0) {
> +				ret = -ENODEV;
> +				goto errfreeipdev;
> +			}
> +		}
> +		/*
> +		 *  If no memory region declared in dt we assume that
> +		 *  the user is okay with plain dma_alloc_coherent.
> +		 */
> +		break;
> +	case ION_HEAP_TYPE_CARVEOUT:
> +	case ION_HEAP_TYPE_CHUNK:
> +	{

Why this unneeded brace?

> +		if (size == 0) {
> +			ret = -EIO;
> +			goto errfreeipdev;
> +		}
> +		ipdev->freepage_ptr = alloc_pages_exact(size, GFP_KERNEL);
> +		if (ipdev->freepage_ptr) {
> +			addr = virt_to_phys(ipdev->freepage_ptr);
> +		} else {
> +			ret = -ENOMEM;
> +			goto errfreeipdev;
> +		}
> +		break;
> +	}
> +	}
> +
> +	ipdev->data.id    = ion_heap_id;
> +	ipdev->data.type  = ion_heap_type;
> +	ipdev->data.name  = ion_heap_name;
> +	ipdev->data.align = ion_heap_align;
> +	ipdev->data.base  = addr;
> +	ipdev->data.size  = size;
> +
> +	/* This one make dma_declare_coherent_memory actually work */
> +	ipdev->data.priv  = &pdev->dev;
> +
> +	ipdev->heap = ion_heap_create(&ipdev->data);
> +	if (!ipdev->heap)
> +		goto errfreeipdev;
> +
> +	/* If it's needed - take care enable clocks */
> +	ipdev->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(ipdev->clk))
> +		ipdev->clk = NULL;
> +	else
> +		clk_prepare_enable(ipdev->clk);
> +
> +	ion_device_add_heap(idev, ipdev->heap);
> +	num_heaps_registered++;
> +	claimed_heap_ids |= (1 << ion_heap_id);
> +
> +	dev_info(&pdev->dev, "heap %s id %d type %d align 0x%x at phys 0x%lx len %lu KiB\n",
> +	       ion_heap_name, ion_heap_id, ion_heap_type, ion_heap_align,
> +	       (unsigned long int) addr, ((unsigned long int) size / 1024));

Don't be noisy for "normal" operations, this should be debug only as no
one really cares.

> +	return 0;
> +
> +errfreeipdev:
> +	kfree(ipdev);
> +	dev_err(&pdev->dev, "Failed to register heap: %s\n",
> +		ion_heap_name);
> +	return -ENOMEM;
> +}
> +
> +static int ion_physmem_remove(struct platform_device *pdev)
> +{
> +	struct physmem_ion_dev *ipdev = platform_get_drvdata(pdev);
> +
> +	ion_heap_destroy(ipdev->heap);
> +	if (ipdev->need_free_coherent)
> +		dma_release_declared_memory(&pdev->dev);
> +	if (ipdev->freepage_ptr)
> +		free_pages_exact(ipdev->freepage_ptr, ipdev->data.size);
> +	kfree(ipdev->heap);
> +	if (ipdev->clk)
> +		clk_disable_unprepare(ipdev->clk);
> +	kfree(ipdev);
> +	num_heaps_registered--;
> +	if (0 == num_heaps_registered) {
> +		ion_device_destroy(idev);
> +		idev = NULL;
> +	}

We really have no other way to do allocation/cleanup than a simple
integer value?  Shouldn't the ion device have reference counting in it?

thanks,

greg k-h