Re: [Linaro-mm-sig] [PATCH v2 3/5] drivers: of: implement reserved-memory handling for cma

On Tue, 04 Feb 2014 13:09:31 +0100, Marek Szyprowski m.szyprowski@samsung.com wrote:

From: Josh Cartwright joshc@codeaurora.org

Add support for handling 'shared-dma-pool' reserved-memory nodes using Contiguous Memory Allocator driver.

Cc: Benjamin Herrenschmidt benh@kernel.crashing.org Cc: Laura Abbott lauraa@codeaurora.org Signed-off-by: Josh Cartwright joshc@codeaurora.org Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com

---

drivers/of/Kconfig | 7 ++++ drivers/of/Makefile | 1 + drivers/of/of_reserved_mem_cma.c | 75 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 83 insertions(+) create mode 100644 drivers/of/of_reserved_mem_cma.c

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig index 7ac330473ec9..5dd3a80910d2 100644 --- a/drivers/of/Kconfig +++ b/drivers/of/Kconfig @@ -81,6 +81,13 @@ config OF_RESERVED_MEM help Helpers to allow for reservation of memory regions +config OF_RESERVED_MEM_CMA

• depends on OF_RESERVED_MEM
• depends on DMA_CMA
• def_bool y
• help

•  Helpers for reserving memory regions for DMA use
  

config OF_RESERVED_MEM_DMA depends on OF_RESERVED_MEM depends on HAVE_GENERIC_DMA_COHERENT diff --git a/drivers/of/Makefile b/drivers/of/Makefile index 6142227ca854..49b9078637b8 100644 --- a/drivers/of/Makefile +++ b/drivers/of/Makefile @@ -10,4 +10,5 @@ obj-$(CONFIG_OF_PCI) += of_pci.o obj-$(CONFIG_OF_PCI_IRQ) += of_pci_irq.o obj-$(CONFIG_OF_MTD) += of_mtd.o obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o +obj-$(CONFIG_OF_RESERVED_MEM_CMA) += of_reserved_mem_cma.o obj-$(CONFIG_OF_RESERVED_MEM_DMA) += of_reserved_mem_dma.o diff --git a/drivers/of/of_reserved_mem_cma.c b/drivers/of/of_reserved_mem_cma.c new file mode 100644 index 000000000000..601d80655102 --- /dev/null +++ b/drivers/of/of_reserved_mem_cma.c @@ -0,0 +1,75 @@ +/*

• • Device tree based initialization code for DMA reserved regions.
• • Copyright (c) 2013, The Linux Foundation. All Rights Reserved.
• • Copyright (c) 2013 Samsung Electronics Co., Ltd.

• • http://www.samsung.com
    

• • Author: Marek Szyprowski m.szyprowski@samsung.com
• • Author: Josh Cartwright joshc@codeaurora.org
• • This program is free software; you can redistribute it and/or
• • modify it under the terms of the GNU General Public License as
• • published by the Free Software Foundation; either version 2 of the
• • License or (at your optional) any later version of the license.
• */

+#include <linux/err.h> +#include <linux/of.h> +#include <linux/of_fdt.h> +#include <linux/of_platform.h> +#include <linux/mm.h> +#include <linux/sizes.h> +#include <linux/mm_types.h> +#include <linux/dma-contiguous.h> +#include <linux/of_reserved_mem.h>

+static void rmem_cma_device_init(struct reserved_mem *rmem,

• 		 struct device *dev,
  

• 		 struct of_phandle_args *args)
  

+{

• struct cma *cma = rmem->priv;
• dev_set_cma_area(dev, cma);

+}

+static const struct reserved_mem_ops rmem_cma_ops = {

• .device_init = rmem_cma_device_init,

+};

+static int __init rmem_cma_setup(struct reserved_mem *rmem,

• 		 unsigned long node,
  

• 		 const char *uname)
  

+{

• struct cma *cma;
• int err;
• if (!of_get_flat_dt_prop(node, "reusable", NULL))

• return -EINVAL;
  

• err = of_parse_flat_dt_reg(node, uname, &rmem->base, &rmem->size);
• if (!err)

• goto out_done;
  

• rmem->base = 0;
• err = of_parse_flat_dt_size(node, uname, &rmem->size);
• if (err)

• goto out_err;
  

+out_done:

Please restrict gotos for error handling. Why not the following:

err = of_parse_flat_dt_reg(node, uname, &rmem->base, &rmem->size); if (err) { rmem->base = 0; err = of_parse_flat_dt_size(node, uname, &rmem->size); if (err) goto out_err; }

• err = dma_contiguous_reserve_area(rmem->size, rmem->base, 0,

• 			  &cma);
  

• if (err) {

• pr_err("Reserved memory: unable to setup CMA region\n");
  

• return err;
  

• }
• if (of_get_flat_dt_prop(node, "linux,cma-default", NULL))

• dma_contiguous_set_default(cma);
  

• rmem->ops = &rmem_cma_ops;
• rmem->priv = cma;
• return 0;

+out_err:

• pr_err("Reseved memory: malformed node '%s'.\n", uname);
• return err;

+}

+RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);

1.7.9.5