[PATCH V2 05/12] ARM: SAMSUNG: Add common DMA operations
Boojin Kim
boojin.kim at samsung.com
Fri Jul 15 20:39:31 EDT 2011
Grant Likely wrote:
> On Wed, Jul 13, 2011 at 05:47:30PM +0900, Kukjin Kim wrote:
> > From: Boojin Kim <boojin.kim at samsung.com>
> >
> > This patch adds common DMA operations which are used for Samsung DMA
> > drivers. Currently there are two types of DMA driver for Samsung SoCs.
> > The one is S3C-DMA for S3C SoCs and the other is PL330-DMA for S5P SoCs.
> > This patch provides funcion pointers for common DMA operations to DMA
> > client driver like SPI and Audio. It makes DMA client drivers support
> > multi-platform.
> > In addition, this common DMA operations implement the shared actions
> > that are needed for DMA client driver. For example shared actions are
> > filter() function for dma_request_channel() and parameter passing for
> > device_prep_slave_sg().
> >
> > Signed-off-by: Boojin Kim <boojin.kim at samsung.com>
> > Signed-off-by: Kukjin Kim <kgene.kim at samsung.com>
> > ---
> > arch/arm/mach-s3c2410/include/mach/dma.h | 3 +-
> > arch/arm/plat-samsung/Makefile | 6 +-
> > arch/arm/plat-samsung/dma-ops.c | 131
> +++++++++++++++++++++++
> > arch/arm/plat-samsung/include/plat/dma-ops.h | 47 +++++++++
> > arch/arm/plat-samsung/include/plat/dma-pl330.h | 3 +
> > arch/arm/plat-samsung/include/plat/dma.h | 2 +-
> > arch/arm/plat-samsung/s3c-dma-ops.c | 132
> ++++++++++++++++++++++++
> > 7 files changed, 320 insertions(+), 4 deletions(-)
> > create mode 100644 arch/arm/plat-samsung/dma-ops.c
> > create mode 100644 arch/arm/plat-samsung/include/plat/dma-ops.h
> > create mode 100644 arch/arm/plat-samsung/s3c-dma-ops.c
> >
> > diff --git a/arch/arm/mach-s3c2410/include/mach/dma.h b/arch/arm/mach-
> s3c2410/include/mach/dma.h
> > index b2b2a5b..71a662d 100644
> > --- a/arch/arm/mach-s3c2410/include/mach/dma.h
> > +++ b/arch/arm/mach-s3c2410/include/mach/dma.h
> > @@ -13,7 +13,6 @@
> > #ifndef __ASM_ARCH_DMA_H
> > #define __ASM_ARCH_DMA_H __FILE__
> >
> > -#include <plat/dma.h>
> > #include <linux/sysdev.h>
> >
> > #define MAX_DMA_TRANSFER_SIZE 0x100000 /* Data Unit is half word */
> > @@ -51,6 +50,8 @@ enum dma_ch {
> > DMACH_MAX, /* the end entry */
> > };
> >
> > +#include <plat/dma.h>
> > +
> > #define DMACH_LOW_LEVEL (1<<28) /* use this to specifiy hardware
> ch no */
> >
> > /* we have 4 dma channels */
> > diff --git a/arch/arm/plat-samsung/Makefile b/arch/arm/plat-
> samsung/Makefile
> > index 53eb15b..9ecf2aa 100644
> > --- a/arch/arm/plat-samsung/Makefile
> > +++ b/arch/arm/plat-samsung/Makefile
> > @@ -62,9 +62,11 @@ obj-$(CONFIG_SAMSUNG_DEV_PWM) += dev-pwm.o
> >
> > # DMA support
> >
> > -obj-$(CONFIG_S3C_DMA) += dma.o
> > +obj-$(CONFIG_S3C_DMA) += dma.o s3c-dma-ops.o
> >
> > -obj-$(CONFIG_S3C_PL330_DMA) += s3c-pl330.o
> > +obj-$(CONFIG_DMADEV_PL330) += dma-ops.o
> > +
> > +obj-$(CONFIG_S3C_PL330_DMA) += s3c-pl330.o s3c-dma-ops.o
> >
> > # PM support
> >
> > diff --git a/arch/arm/plat-samsung/dma-ops.c b/arch/arm/plat-
> samsung/dma-ops.c
> > new file mode 100644
> > index 0000000..94a9d33
> > --- /dev/null
> > +++ b/arch/arm/plat-samsung/dma-ops.c
> > @@ -0,0 +1,131 @@
> > +/* linux/arch/arm/plat-samsung/dma-ops.c
> > + *
> > + * Copyright (c) 2011 Samsung Electronics Co., Ltd.
> > + * http://www.samsung.com
> > + *
> > + * Samsung DMA Operations
> > + *
> > + * 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/errno.h>
> > +#include <linux/dmaengine.h>
> > +#include <linux/amba/pl330.h>
> > +
> > +#include <mach/dma.h>
> > +
> > +static bool filter(struct dma_chan *chan, void *param)
> > +{
> > + struct dma_pl330_peri *peri = (struct dma_pl330_peri *)chan-
> >private;
>
> Is this code pl330 specific? If so, 'pl330' should probably be
> referenced in the function name.
I will address your comment.
>
> > + unsigned dma_ch = (unsigned)param;
> > +
> > + if (peri->peri_id != dma_ch)
> > + return false;
> > +
> > + return true;
> > +}
> > +
> > +static unsigned dma_request(enum dma_ch dma_ch, struct samsung_dma_info
> *info)
> > +{
> > + struct dma_chan *chan;
> > + dma_cap_mask_t mask;
> > + struct dma_slave_config slave_config;
> > +
> > + dma_cap_zero(mask);
> > + dma_cap_set(info->cap, mask);
> > +
> > + chan = dma_request_channel(mask, filter, (void *)dma_ch);
> > +
> > + if (info->direction == DMA_FROM_DEVICE) {
> > + memset(&slave_config, 0, sizeof(struct dma_slave_config));
> > + slave_config.direction = info->direction;
> > + slave_config.src_addr = info->fifo;
> > + slave_config.src_addr_width = info->width;
> > + dmaengine_slave_config(chan, &slave_config);
> > + } else if (info->direction == DMA_TO_DEVICE) {
> > + memset(&slave_config, 0, sizeof(struct dma_slave_config));
> > + slave_config.direction = info->direction;
> > + slave_config.dst_addr = info->fifo;
> > + slave_config.dst_addr_width = info->width;
> > + dmaengine_slave_config(chan, &slave_config);
> > + }
> > +
> > + return (unsigned)chan;
> > +}
> > +
> > +static int dma_release(unsigned ch, struct s3c2410_dma_client *client)
> > +{
> > + dma_release_channel((struct dma_chan *)ch);
> > +
> > + return 0;
> > +}
> > +
> > +static int dma_prepare(unsigned ch, struct samsung_dma_prep_info *info)
> > +{
> > + struct scatterlist sg;
> > + struct dma_chan *chan = (struct dma_chan *)ch;
> > + struct dma_async_tx_descriptor *desc;
> > +
> > + switch (info->cap) {
> > + case DMA_SLAVE:
> > + sg_init_table(&sg, 1);
> > + sg_dma_len(&sg) = info->len;
> > + sg_set_page(&sg, pfn_to_page(PFN_DOWN(info->buf)),
> > + info->len, offset_in_page(info->buf));
> > + sg_dma_address(&sg) = info->buf;
> > +
> > + desc = chan->device->device_prep_slave_sg(chan,
> > + &sg, 1, info->direction, DMA_PREP_INTERRUPT);
> > + break;
> > + case DMA_CYCLIC:
> > + desc = chan->device->device_prep_dma_cyclic(chan,
> > + info->buf, info->len, info->period,
info->direction);
> > + break;
> > + default:
> > + dev_err(&chan->dev->device, "unsupported format\n");
> > + return -EFAULT;
> > + }
> > +
> > + if (!desc) {
> > + dev_err(&chan->dev->device, "cannot prepare cyclic dma\n");
> > + return -EFAULT;
> > + }
> > +
> > + desc->callback = info->fp;
> > + desc->callback_param = info->fp_param;
> > +
> > + dmaengine_submit((struct dma_async_tx_descriptor *)desc);
> > +
> > + return 0;
> > +}
> > +
> > +static inline int dma_trigger(unsigned ch)
> > +{
> > + dma_async_issue_pending((struct dma_chan *)ch);
> > +
> > + return 0;
> > +}
> > +
> > +static inline int dma_flush(unsigned ch)
> > +{
> > + return dmaengine_terminate_all((struct dma_chan *)ch);
> > +}
> > +
> > +static struct samsung_dma_ops dmaeng_ops = {
> > + .request = dma_request,
> > + .release = dma_release,
> > + .prepare = dma_prepare,
> > + .trigger = dma_trigger,
> > + .started = NULL,
> > + .flush = dma_flush,
> > + .stop = dma_flush,
> > +};
>
> Even though these function are all local statics, you should use a
> samsung prefix to avoid namespace collisions. So, they should be
> named something like: samsung_dmaeng_ops, samsung_dmaeng_request(),
> samsung_dmaeng_release(), etc. The ops structure and the functions
> should have the same prefix.
I will address your comment.
>
> > +
> > +void *samsung_dma_get_ops(void)
> > +{
> > + return (void *)&dmaeng_ops;
> > +}
> > +EXPORT_SYMBOL(samsung_dma_get_ops);
>
> If all that is needed is a reference to the dma ops, then you could
> simply export samsung_dmaeng_ops() without a separate function.
Grant, Thanks for your comments. I can't understand this comment well.
Do you mean to change function name from 'samsung_dma_get_ops()' to
'samsung_dmaeng_ops()' ?
Or export 'dmaeng_ops' variable instead of making this
'samsung_dma_get_ops()' function
>
> > diff --git a/arch/arm/plat-samsung/include/plat/dma-ops.h
> b/arch/arm/plat-samsung/include/plat/dma-ops.h
> > new file mode 100644
> > index 0000000..eea4130
> > --- /dev/null
> > +++ b/arch/arm/plat-samsung/include/plat/dma-ops.h
> > @@ -0,0 +1,47 @@
> > +/* arch/arm/plat-samsung/include/plat/dma-ops.h
> > + *
> > + * Copyright (c) 2011 Samsung Electronics Co., Ltd.
> > + * http://www.samsung.com
> > + *
> > + * Samsung DMA support
> > + *
> > + * 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/dmaengine.h>
> > +
> > +struct samsung_dma_prep_info {
> > + enum dma_transaction_type cap;
> > + enum dma_data_direction direction;
> > + unsigned buf;
> > + unsigned long period;
> > + unsigned long len;
> > + void (*fp)(void *data);
> > + void *fp_param;
> > +};
> > +
> > +struct samsung_dma_info {
> > + enum dma_transaction_type cap;
> > + enum dma_data_direction direction;
> > + enum dma_slave_buswidth width;
> > + unsigned fifo;
> > + struct s3c2410_dma_client *client;
> > +};
> > +
> > +struct samsung_dma_ops {
> > + unsigned (*request)(enum dma_ch ch, struct samsung_dma_info *info);
> > + int (*release)(unsigned ch, struct s3c2410_dma_client *client);
> > + int (*prepare)(unsigned ch, struct samsung_dma_prep_info *info);
> > + int (*trigger)(unsigned ch);
> > + int (*started)(unsigned ch);
> > + int (*flush)(unsigned ch);
> > + int (*stop)(unsigned ch);
> > +};
> > +
> > +/*
> > + * samsung_dma_get_ops
> > + * get the set of dma operations
> > + */
> > +extern void *samsung_dma_get_ops(void);
> > diff --git a/arch/arm/plat-samsung/include/plat/dma-pl330.h
> b/arch/arm/plat-samsung/include/plat/dma-pl330.h
> > index c402719..be84bec 100644
> > --- a/arch/arm/plat-samsung/include/plat/dma-pl330.h
> > +++ b/arch/arm/plat-samsung/include/plat/dma-pl330.h
> > @@ -1,4 +1,7 @@
> > /*
> > + * Copyright (c) 2011 Samsung Electronics Co., Ltd.
> > + * http://www.samsung.com
> > + *
> > * Copyright (C) 2010 Samsung Electronics Co. Ltd.
> > * Jaswinder Singh <jassi.brar at samsung.com>
> > *
>
>
> Heh, this patch doesn't make any changes to this file, and samsung
> already has a copyright notice on it anyway. You should probably drop
> this hunk.
I will address your comment.
>
> > diff --git a/arch/arm/plat-samsung/include/plat/dma.h b/arch/arm/plat-
> samsung/include/plat/dma.h
> > index 2e8f8c6..90da162 100644
> > --- a/arch/arm/plat-samsung/include/plat/dma.h
> > +++ b/arch/arm/plat-samsung/include/plat/dma.h
> > @@ -124,4 +124,4 @@ extern int s3c2410_dma_getposition(unsigned int
> channel,
> > extern int s3c2410_dma_set_opfn(unsigned int, s3c2410_dma_opfn_t rtn);
> > extern int s3c2410_dma_set_buffdone_fn(unsigned int, s3c2410_dma_cbfn_t
> rtn);
> >
> > -
>
> nitpick: Unrelated whitespace change. One blank line of whitespace is
> sufficient anyway.
I will address your comment.
> > +#include <plat/dma-ops.h>
> > diff --git a/arch/arm/plat-samsung/s3c-dma-ops.c b/arch/arm/plat-
> samsung/s3c-dma-ops.c
> > new file mode 100644
> > index 0000000..17b1be0
> > --- /dev/null
> > +++ b/arch/arm/plat-samsung/s3c-dma-ops.c
> > @@ -0,0 +1,132 @@
> > +/* linux/arch/arm/plat-samsung/s3c-dma-ops.c
> > + *
> > + * Copyright (c) 2011 Samsung Electronics Co., Ltd.
> > + * http://www.samsung.com
> > + *
> > + * Samsung S3C-DMA Operations
> > + *
> > + * 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/errno.h>
> > +#include <linux/slab.h>
> > +#include <linux/types.h>
> > +
> > +#include <mach/dma.h>
> > +
> > +struct cb_data {
>
> struct s3c2410_cb_data {
>
> > + void (*fp) (void *);
> > + void *fp_param;
> > + unsigned ch;
> > + struct list_head node;
> > +};
> > +
> > +static LIST_HEAD(dma_list);
> > +
> > +static void dma_cb(struct s3c2410_dma_chan *channel,
> > + void *param, int size, enum s3c2410_dma_buffresult res)
> > +{
> > + struct cb_data *data = (struct cb_data *)param;
>
> param is a void*. The (struct cb_data*) cast is not needed.
>
> > +
> > + data->fp(data->fp_param);
> > +}
> > +
> > +static unsigned dma_request(enum dma_ch dma_ch, struct samsung_dma_info
> *info)
>
> These functions should *definitely* be named differently from the
> dma_* ops in the other file so that you can differentiate between
> them, and to make them grep-friendly. This goes for *all* file-scope
> symbols.
I will address your comment.
>
> > +{
> > + struct cb_data *data;
> > +
> > + if (s3c2410_dma_request(dma_ch, info->client, NULL) < 0) {
> > + s3c2410_dma_free(dma_ch, info->client);
> > + return 0;
> > + }
> > +
> > + data = kmalloc(sizeof(struct cb_data), GFP_KERNEL);
>
> kzalloc()
>
> > + data->fp = NULL;
>
> Drop this line after converting to kzalloc()
I will address your comment.
>
> > + data->ch = (unsigned)dma_ch;
>
> Is the cast necessary?
>
> > + list_add_tail(&data->node, &dma_list);
> > +
> > + if (info->direction == DMA_FROM_DEVICE)
> > + s3c2410_dma_devconfig(dma_ch, S3C2410_DMASRC_HW,
info->fifo);
> > + else
> > + s3c2410_dma_devconfig(dma_ch, S3C2410_DMASRC_MEM, info-
> >fifo);
>
> From arch/arm/plat-samsung/include/plat/dma.h:
> enum s3c2410_dmasrc {
> S3C2410_DMASRC_HW, /* source is memory */
> S3C2410_DMASRC_MEM /* source is hardware */
> };
>
> from dma-mapping.h:
> enum dma_data_direction {
> DMA_BIDIRECTIONAL = 0,
> DMA_TO_DEVICE = 1,
> DMA_FROM_DEVICE = 2,
> DMA_NONE = 3,
> };
>
> /me thinks it would all look nicer if s3c2410 dma just replaced
> s3c2410_dmasrc to dma_data_direction, and from what I can tell it
> would just be a simple search and replace. :-)
>
I will address your comment.
> > +
> > + if (info->cap == DMA_CYCLIC)
> > + s3c2410_dma_setflags(dma_ch, S3C2410_DMAF_CIRCULAR);
> > +
> > + s3c2410_dma_config(dma_ch, info->width);
> > +
> > + return (unsigned)dma_ch;
> > +}
> > +
> > +static int dma_release(unsigned ch, struct s3c2410_dma_client *client)
>
> unsigned int
>
> > +{
> > + struct cb_data *data;
> > +
> > + list_for_each_entry(data, &dma_list, node)
> > + if (data->ch == ch)
> > + break;
>
> nit: incorrect indentation. Use tab characters instead of spaces.
> I've got "set list" and "set listchars=tab:\|-,trail:-" in my ~/.vimrc
> so I can see the difference between tabs and spaces.
>
I will address your comment.
> > + list_del(&data->node);
>
> What happens if the channel isn't found in the list? Can that
> situation happen?
>
> What happens if two drivers call dma_release simultaneously? It
> looks like a mutex is needed to protext the dma_list.
>
> > +
> > + s3c2410_dma_free((enum dma_ch)ch, client);
>
> All the casting in this patch makes me nervous. When a lot of casting
> is required, I wonder if the API needs to be changed.
I will remove casting to "enum dma_ch"
>
> > + kfree(data);
> > +
> > + return 0;
> > +}
> > +
> > +static int dma_prepare(unsigned ch, struct samsung_dma_prep_info *info)
> > +{
> > + struct cb_data *data;
> > +
> > + list_for_each_entry(data, &dma_list, node)
> > + if (data->ch == ch)
> > + break;
> > +
> > + if (!data->fp) {
> > + s3c2410_dma_set_buffdone_fn((enum dma_ch)ch, dma_cb);
> > + data->fp = info->fp;
> > + data->fp_param = info->fp_param;
> > + }
> > + s3c2410_dma_enqueue((enum dma_ch)ch, (void *)data, info->buf,
> > + info->period);
> > +
> > + return 0;
> > +}
> > +
> > +static inline int dma_trigger(unsigned ch)
> > +{
> > + return s3c2410_dma_ctrl(ch, S3C2410_DMAOP_START);
> > +}
> > +
> > +static inline int dma_started(unsigned ch)
> > +{
> > + return s3c2410_dma_ctrl(ch, S3C2410_DMAOP_STARTED);
> > +}
> > +
> > +static inline int dma_flush(unsigned ch)
> > +{
> > + return s3c2410_dma_ctrl(ch, S3C2410_DMAOP_FLUSH);
> > +}
> > +
> > +static inline int dma_stop(unsigned ch)
> > +{
> > + return s3c2410_dma_ctrl(ch, S3C2410_DMAOP_STOP);
> > +}
> > +
> > +static struct samsung_dma_ops s3c_dma_ops = {
> > + .request = dma_request,
> > + .release = dma_release,
> > + .prepare = dma_prepare,
> > + .trigger = dma_trigger,
> > + .started = dma_started,
> > + .flush = dma_flush,
> > + .stop = dma_stop,
> > +};
> > +
> > +void *samsung_dma_get_ops(void)
> > +{
> > + return (void *)&s3c_dma_ops;
> > +}
> > +EXPORT_SYMBOL(samsung_dma_get_ops);
>
> This is a problem. This patch adds two implementations of
> samsung_dma_get_ops(). New code needs to be multiplatform friendly.
> That means that the code nees to handle both dma-ops.c and
> s3c-dma-ops.c compiled into the kernel at the same time and select the
> correct one at runtime.
>
I will address your comment.
> g.
>
> > --
> > 1.7.1
> >
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