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Date: Mon, 27 May 2013 00:15:53 +0200
From: Stefan Richter <stefanr@...6.in-berlin.de>
To: Stefan Richter <stefanr@...6.in-berlin.de>
Cc: Takashi Sakamoto <o-takashi@...amocchi.jp>,
linux1394-devel@...ts.sourceforge.net,
linux-kernel@...r.kernel.org,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Clemens Ladisch <clemens@...isch.de>
Subject: Re: How to get driver_data of struct ieee1394_device_id in kernel
driver module?
On May 26 Stefan Richter wrote:
> (Adding LKML and Greg KH, in case that there are general opinions about
> how a bus_type should work.)
>
> On May 26 Takashi Sakamoto wrote:
> > Hi all,
> >
> > I'm a newbile for Linux Firewire subsystem and not used to IEEE 1394 bus
> > programing in Linux.
> > So I happy to get your advices.
> >
> > Currently I'm working for some drivers of ALSA in kernel land.
> > Then some devices to which the same module applies need to handle its
> > own operations.
> > To implement these operations, I think it good to utilize driver_data of
> > struct ieee1394_evice_id entry.
> >
> > This is example.
> > For entry:
> > https://github.com/takaswie/snd-firewire-improve/blob/f509e4587c3f7b18eda70d07b616ef01be3546ef/bebob/bebob.c#L462
> > For usage:
> > https://github.com/takaswie/snd-firewire-improve/blob/f509e4587c3f7b18eda70d07b616ef01be3546ef/bebob/bebob.c#L362
> >
> > (In this case, I use the cast between (kernel_ulong_t) and (struct
> > snd_bebob_ops *) but I have no confidence that this is better...)
> >
> > Anyway, this module need to know the id for the current device in
> > device_id table but I have no idea to get the id. Do you know good way
> > to get it in module's probing process?
> >
> >
> > Regards
> >
> > Takashi Sakamoto
>
> I think your approach is sensible. There is of course just the little
> problem that firewire-core keeps the matching device_id table entry as a
> secret to itself. Therefore, struct ieee1394_device_id.driver_data is
> currently totally useless.
>
> How about we make it available like in the following patch?
From: Stefan Richter <stefanr@...6.in-berlin.de>
Subject: firewire: pass matching ieee1394_device_id to drivers via struct fw_unit
FireWire audio unit drivers will need to apply various model-specific
operations. The struct ieee1394_device_id.driver_data member can be
used to store respective flags or function pointer tables.
But until now drivers had no way to know which driver->id_table index
was matched with an fw_unit instance. Other bus subsystems like pci or
usb pass this information via an own driver probe method, whereas the
firewire subsystem uses the stock struct device_driver.probe().
We could introduce a struct fw_driver.probe() which works similarly to
struct pci_driver.probe() or struct usb_driver.probe(). But it seems
simpler to just add a new member to struct fw_unit which caches the
matching ieee1394_device_id, so this is what is done here, and used in
the snd-firewire-speakers driver.
Signed-off-by: Stefan Richter <stefanr@...6.in-berlin.de>
---
drivers/firewire/core-device.c | 7 +++-
include/linux/firewire.h | 5 ++-
sound/firewire/speakers.c | 65 ++++++++++++---------------------
3 files changed, 32 insertions(+), 45 deletions(-)
--- a/drivers/firewire/core-device.c
+++ b/drivers/firewire/core-device.c
@@ -168,21 +168,24 @@ static bool match_ids(const struct ieee1
static bool is_fw_unit(struct device *dev);
static int fw_unit_match(struct device *dev, struct device_driver *drv)
{
+ struct fw_unit *unit = fw_unit(dev);
const struct ieee1394_device_id *id_table =
container_of(drv, struct fw_driver, driver)->id_table;
int id[] = {0, 0, 0, 0};
/* We only allow binding to fw_units. */
if (!is_fw_unit(dev))
return 0;
- get_modalias_ids(fw_unit(dev), id);
+ get_modalias_ids(unit, id);
for (; id_table->match_flags != 0; id_table++)
- if (match_ids(id_table, id))
+ if (match_ids(id_table, id)) {
+ unit->device_id = id_table;
return 1;
+ }
return 0;
}
--- a/include/linux/firewire.h
+++ b/include/linux/firewire.h
@@ -215,14 +215,17 @@ static inline int fw_device_is_shutdown(
}
int fw_device_enable_phys_dma(struct fw_device *device);
+struct ieee1394_device_id;
+
/*
* fw_unit.directory must not be accessed after device_del(&fw_unit.device).
*/
struct fw_unit {
struct device device;
const u32 *directory;
+ const struct ieee1394_device_id *device_id;
struct fw_attribute_group attribute_group;
};
static inline struct fw_unit *fw_unit(struct device *dev)
@@ -246,10 +249,8 @@ static inline struct fw_device *fw_paren
{
return fw_device(unit->device.parent);
}
-struct ieee1394_device_id;
-
struct fw_driver {
struct device_driver driver;
/* Called when the parent device sits through a bus reset. */
void (*update)(struct fw_unit *unit);
--- a/sound/firewire/speakers.c
+++ b/sound/firewire/speakers.c
@@ -657,44 +657,8 @@ static void fwspk_card_free(struct snd_c
fw_unit_put(fwspk->unit);
mutex_destroy(&fwspk->mutex);
}
-static const struct device_info *fwspk_detect(struct fw_device *dev)
-{
- static const struct device_info griffin_firewave = {
- .driver_name = "FireWave",
- .short_name = "FireWave",
- .long_name = "Griffin FireWave Surround",
- .pcm_constraints = firewave_constraints,
- .mixer_channels = 6,
- .mute_fb_id = 0x01,
- .volume_fb_id = 0x02,
- };
- static const struct device_info lacie_speakers = {
- .driver_name = "FWSpeakers",
- .short_name = "FireWire Speakers",
- .long_name = "LaCie FireWire Speakers",
- .pcm_constraints = lacie_speakers_constraints,
- .mixer_channels = 1,
- .mute_fb_id = 0x01,
- .volume_fb_id = 0x01,
- };
- struct fw_csr_iterator i;
- int key, value;
-
- fw_csr_iterator_init(&i, dev->config_rom);
- while (fw_csr_iterator_next(&i, &key, &value))
- if (key == CSR_VENDOR)
- switch (value) {
- case VENDOR_GRIFFIN:
- return &griffin_firewave;
- case VENDOR_LACIE:
- return &lacie_speakers;
- }
-
- return NULL;
-}
-
static int fwspk_probe(struct device *unit_dev)
{
struct fw_unit *unit = fw_unit(unit_dev);
struct fw_device *fw_dev = fw_parent_device(unit);
@@ -711,13 +675,10 @@ static int fwspk_probe(struct device *un
fwspk = card->private_data;
fwspk->card = card;
mutex_init(&fwspk->mutex);
fwspk->unit = fw_unit_get(unit);
- fwspk->device_info = fwspk_detect(fw_dev);
- if (!fwspk->device_info) {
- err = -ENODEV;
- goto err_unit;
- }
+ fwspk->device_info =
+ (const struct device_info *)unit->device_id->driver_data;
err = cmp_connection_init(&fwspk->connection, unit, 0);
if (err < 0)
goto err_unit;
@@ -797,8 +758,28 @@ static void fwspk_bus_reset(struct fw_un
amdtp_stream_update(&fwspk->stream);
}
+static const struct device_info griffin_firewave = {
+ .driver_name = "FireWave",
+ .short_name = "FireWave",
+ .long_name = "Griffin FireWave Surround",
+ .pcm_constraints = firewave_constraints,
+ .mixer_channels = 6,
+ .mute_fb_id = 0x01,
+ .volume_fb_id = 0x02,
+};
+
+static const struct device_info lacie_speakers = {
+ .driver_name = "FWSpeakers",
+ .short_name = "FireWire Speakers",
+ .long_name = "LaCie FireWire Speakers",
+ .pcm_constraints = lacie_speakers_constraints,
+ .mixer_channels = 1,
+ .mute_fb_id = 0x01,
+ .volume_fb_id = 0x01,
+};
+
static const struct ieee1394_device_id fwspk_id_table[] = {
{
.match_flags = IEEE1394_MATCH_VENDOR_ID |
IEEE1394_MATCH_MODEL_ID |
@@ -807,8 +788,9 @@ static const struct ieee1394_device_id f
.vendor_id = VENDOR_GRIFFIN,
.model_id = 0x00f970,
.specifier_id = SPECIFIER_1394TA,
.version = VERSION_AVC,
+ .driver_data = (kernel_ulong_t)&griffin_firewave,
},
{
.match_flags = IEEE1394_MATCH_VENDOR_ID |
IEEE1394_MATCH_MODEL_ID |
@@ -817,8 +799,9 @@ static const struct ieee1394_device_id f
.vendor_id = VENDOR_LACIE,
.model_id = 0x00f970,
.specifier_id = SPECIFIER_1394TA,
.version = VERSION_AVC,
+ .driver_data = (kernel_ulong_t)&lacie_speakers,
},
{ }
};
MODULE_DEVICE_TABLE(ieee1394, fwspk_id_table);
--
Stefan Richter
-=====-===-= -=-= ==-==
http://arcgraph.de/sr/
--
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