Subject: [PATCH 13/23] AT91 DMA OF support

From: [email-masked] (Nicolas Ferre)
Date: Tue, 14 Aug 2012 16:47:05 +0200

Hi Richard,

I am not sure that this one will go further: there is an initiative to
build a pretty generic DMA OF support... It takes time but it is
progressing...

Anyway, there may have some bits to integrate in at_hdmac.c driver: I
will have a closer look later.

Thanks,

On 08/14/2012 03:49 PM, Richard Genoud :
> Signed-off-by: Richard Genoud <[email-masked]>
> ---
>  arch/arm/mach-at91/include/mach/at_hdmac.h |    1 +
>  drivers/of/Kconfig                         |    4 +
>  drivers/of/Makefile                        |    1 +
>  drivers/of/of_atmel.c                      |  112 ++++++++++++++++++++++++++++
>  include/linux/of_atmel.h                   |   29 +++++++
>  5 files changed, 147 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/of/of_atmel.c
>  create mode 100644 include/linux/of_atmel.h
> 
> diff --git a/arch/arm/mach-at91/include/mach/at_hdmac.h b/arch/arm/mach-at91/include/mach/at_hdmac.h
> index cab0997..35667bd 100644
> --- a/arch/arm/mach-at91/include/mach/at_hdmac.h
> +++ b/arch/arm/mach-at91/include/mach/at_hdmac.h
> @@ -52,6 +52,7 @@ struct at_dma_slave {
>  #define		ATC_LOCK_IF_L_CHUNK	(0x0 << 22)
>  #define		ATC_LOCK_IF_L_BUFFER	(0x1 << 22)
>  #define	ATC_AHB_PROT_MASK	(0x7 << 24)	/* AHB Protection */
> +#define	ATC_AHB_PROT(h)		(((h) <<  24) && ATC_AHB_PROT_MASK)
>  #define	ATC_FIFOCFG_MASK	(0x3 << 28)	/* FIFO Request Configuration */
>  #define		ATC_FIFOCFG_LARGESTBURST	(0x0 << 28)
>  #define		ATC_FIFOCFG_HALFFIFO		(0x1 << 28)
> diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
> index dfba3e6..4667960 100644
> --- a/drivers/of/Kconfig
> +++ b/drivers/of/Kconfig
> @@ -83,4 +83,8 @@ config OF_MTD
>  	depends on MTD
>  	def_bool y
>  
> +config OF_ATMEL
> +	depends on AT_HDMAC
> +	def_bool y
> +
>  endmenu # OF
> diff --git a/drivers/of/Makefile b/drivers/of/Makefile
> index e027f44..897de3b 100644
> --- a/drivers/of/Makefile
> +++ b/drivers/of/Makefile
> @@ -11,3 +11,4 @@ obj-$(CONFIG_OF_MDIO)	+= of_mdio.o
>  obj-$(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_ATMEL)	+= of_atmel.o
> diff --git a/drivers/of/of_atmel.c b/drivers/of/of_atmel.c
> new file mode 100644
> index 0000000..bcd3c54a
> --- /dev/null
> +++ b/drivers/of/of_atmel.c
> @@ -0,0 +1,112 @@
> +/*
> + * Copyright (C) 2012 Richard Genoud, Paratronic S.A.
> + *                    <[email-masked]>
> + *
> + * Atmel specifics OF helpers
> + *
> + * 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.
> + *
> + */
> +#include <linux/kernel.h>
> +#include <linux/export.h>
> +#include <linux/device.h>
> +#include <linux/slab.h>
> +#include <linux/printk.h>
> +#include <linux/byteorder/generic.h>
> +#include <mach/at_hdmac.h>
> +#include <linux/of.h>
> +
> +static int of_dev_node_match(struct device *dev, void *data)
> +{
> +	return dev->of_node == data;
> +}
> +
> +/**
> + * of_create_at_dma_slave - Alloc and initialize the struct at_dma_slave
> + * @np: pointer to node to create the struct for
> + * @bus: pointer to the bus type of the DMA device.
> + *
> + * Returns pointer to created DMA slave structure, or NULL in case of error.
> + */
> +struct at_dma_slave *of_create_at_dma_slave(struct device_node *np,
> +					    struct bus_type *bus)
> +{
> +	struct at_dma_slave *atslave;
> +	struct device_node *n;
> +	struct property *prop;
> +	const __be32 *dma_list;
> +	phandle phandle;
> +	int size;
> +	int err = -1;
> +	u32 val;
> +
> +	atslave = kzalloc(sizeof(struct at_dma_slave), GFP_KERNEL);
> +	if (unlikely(!atslave)) {
> +		pr_err("cannot allocate memory\n");
> +		goto error;
> +	}
> +
> +	atslave->cfg |= of_property_read_bool(np, "atc_src_rep") ? ATC_SRC_REP : 0;
> +	atslave->cfg |= of_property_read_bool(np, "atc_dst_rep") ? ATC_DST_REP : 0;
> +	atslave->cfg |= of_property_read_bool(np, "atc_src_h2sel_hw") ? ATC_SRC_H2SEL_HW : 0;
> +	atslave->cfg |= of_property_read_bool(np, "atc_dst_h2sel_hw") ? ATC_DST_H2SEL_HW : 0;
> +	atslave->cfg |= of_property_read_bool(np, "atc_sod") ? ATC_SOD : 0;
> +	atslave->cfg |= of_property_read_bool(np, "atc_lock_if") ? ATC_LOCK_IF : 0;
> +	atslave->cfg |= of_property_read_bool(np, "atc_lock_b") ? ATC_LOCK_B : 0;
> +	atslave->cfg |= of_property_read_bool(np, "atc_lock_if_l") ? ATC_LOCK_IF_L : 0;
> +	atslave->cfg |= of_property_read_bool(np, "atc_lock_if_l_buffer") ? ATC_LOCK_IF_L_BUFFER : 0;
> +	if (of_property_read_bool(np, "atc_fifocfg_halffifo"))
> +		atslave->cfg = (atslave->cfg & ~ATC_FIFOCFG_MASK) | ATC_FIFOCFG_HALFFIFO;
> +	if (of_property_read_bool(np, "atc_fifocfg_enoughspace"))
> +		atslave->cfg = (atslave->cfg & ~ATC_FIFOCFG_MASK) | ATC_FIFOCFG_ENOUGHSPACE;
> +	if (of_property_read_bool(np, "atc_fifocfg_largestburst"))
> +		atslave->cfg = (atslave->cfg & ~ATC_FIFOCFG_MASK) | ATC_FIFOCFG_LARGESTBURST;
> +	if (!of_property_read_u32(np, "atc_ahb_prot", &val))
> +		atslave->cfg |= ATC_AHB_PROT(val);
> +	if (!of_property_read_u32(np, "atc_src_per", &val))
> +		atslave->cfg |= ATC_SRC_PER(val);
> +	if (!of_property_read_u32(np, "atc_dst_per", &val))
> +		atslave->cfg |= ATC_DST_PER(val);
> +
> +	/* we need to associate the wanted dma struct device to
> +	 * atslave->dma_dev. This is needed when searching for
> +	 * a free dma channel
> +	 */
> +	prop = of_find_property(np, "dma", &size);
> +	if (!prop) {
> +		pr_err("can't find the dma child node\n");
> +		goto error;
> +	}
> +	dma_list = prop->value;
> +	size /= sizeof(*dma_list);
> +	if (size != 1) {
> +		pr_err("only one dma handle is supported\n");
> +		goto error;
> +	}
> +
> +	phandle = be32_to_cpup(dma_list);
> +	n = of_find_node_by_phandle(phandle);
> +	if (!n) {
> +		pr_err("unable to find dma device: invalid phandle %s\n",
> +		       prop->name);
> +		goto error;
> +	}
> +
> +	atslave->dma_dev = bus_find_device(bus, NULL, n, of_dev_node_match);
> +	if (!atslave->dma_dev) {
> +		pr_err("can't find struct device for DMA %s\n", prop->name);
> +		goto error;
> +	}
> +
> +	pr_debug("DMA cfg register=0x%x DMA device path=%s\n",
> +		 atslave->cfg, prop->name);
> +	err = 0;
> +error:
> +	if (err)
> +		kfree(atslave);
> +	return atslave;
> +}
> +EXPORT_SYMBOL_GPL(of_create_at_dma_slave);
> +
> diff --git a/include/linux/of_atmel.h b/include/linux/of_atmel.h
> new file mode 100644
> index 0000000..256f336
> --- /dev/null
> +++ b/include/linux/of_atmel.h
> @@ -0,0 +1,29 @@
> +#ifndef _LINUX_OF_ATMEL_H
> +#define _LINUX_OF_ATMEL_H
> +/*
> + * Copyright (C) 2012 Richard Genoud, Paratronic S.A.
> + *                    <[email-masked]>
> + *
> + * Atmel specifics OF helpers
> + *
> + * 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.
> + *
> + */
> +#include <linux/of.h>
> +#include <linux/device.h>
> +#include <mach/at_hdmac.h>
> +
> +#ifdef CONFIG_OF_ATMEL
> +extern struct at_dma_slave *of_create_at_dma_slave(struct device_node *np,
> +						   struct bus_type *bus);
> +#else
> +static struct at_dma_slave *of_create_at_dma_slave(struct device_node *np,
> +						   struct bus_type *bus)
> +{
> +	return NULL;
> +}
> +#endif /* CONFIG_OF_ATMEL */
> +
> +#endif	/* _LINUX_OF_ATMEL_H */
> 

-- 
Nicolas Ferre