The SPI subsystem core now manages message queues internally. Remove the
local message queue implementation from the spi-bitbang driver and
migrate to the common one.
Signed-off-by: Guennadi Liakhovetski <g.liakhovet...@gmx.de>
---
On Fri, 16 Mar 2012, Linus Walleij wrote:
> On Thu, Mar 15, 2012 at 10:29 AM, Grant Likely
> <grant.lik...@secretlab.ca> wrote:
> > On Wed, 14 Mar 2012 22:04:25 +0100 (CET), Guennadi Liakhovetski
> > <g.liakhovet...@gmx.de> wrote:
> >> This patch adds a PM QoS requirement to the spi-bitbang driver, preventing
> >> the underlying SPI hardware driver to suspend for too long a time, as long
> >> as there are transfers on the queue.
> >>
> >> Signed-off-by: Guennadi Liakhovetski <g.liakhovet...@gmx.de>
> >
> > Shouldn't this be part of the core spi infrastructure? Particularly since
> > queuing
> > is moving into the core.
>
> Hm, the spi-bitbang driver needs to be converted to use the central
> message queue, Guennadi can you look into that since you're using it?
>
> The spi-pl022.c and also Samsung spi-s3c64xx.c is converted showing
> examples on how go about with that.
Something like this? Tested with spi-sh-msiof on SuperH and sh-mobile ARM
and with spi-gpio.
drivers/spi/spi-bitbang.c | 280 +++++++++++++++------------------------
include/linux/spi/spi_bitbang.h | 7 -
2 files changed, 108 insertions(+), 179 deletions(-)
diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c
index 6c0ec81..5f163d9 100644
--- a/drivers/spi/spi-bitbang.c
+++ b/drivers/spi/spi-bitbang.c
@@ -244,162 +244,125 @@ static int spi_bitbang_bufs(struct spi_device *spi,
struct spi_transfer *t)
/*----------------------------------------------------------------------*/
-/*
- * SECOND PART ... simple transfer queue runner.
- *
- * This costs a task context per controller, running the queue by
- * performing each transfer in sequence. Smarter hardware can queue
- * several DMA transfers at once, and process several controller queues
- * in parallel; this driver doesn't match such hardware very well.
- *
- * Drivers can provide word-at-a-time i/o primitives, or provide
- * transfer-at-a-time ones to leverage dma or fifo hardware.
- */
-static void bitbang_work(struct work_struct *work)
+static int spi_bitbang_transfer_one_message(struct spi_master *master,
+ struct spi_message *msg)
{
- struct spi_bitbang *bitbang =
- container_of(work, struct spi_bitbang, work);
+ struct spi_bitbang *bitbang = spi_master_get_devdata(master);
+ struct spi_device *spi = msg->spi;
+ unsigned nsecs;
+ struct spi_transfer *t = NULL;
unsigned long flags;
- struct spi_message *m, *_m;
+ unsigned cs_change;
+ int status;
+ int do_setup = -1;
+ /* Protect against chip-select release in .setup() */
spin_lock_irqsave(&bitbang->lock, flags);
bitbang->busy = 1;
- list_for_each_entry_safe(m, _m, &bitbang->queue, queue) {
- struct spi_device *spi;
- unsigned nsecs;
- struct spi_transfer *t = NULL;
- unsigned tmp;
- unsigned cs_change;
- int status;
- int do_setup = -1;
-
- list_del(&m->queue);
- spin_unlock_irqrestore(&bitbang->lock, flags);
-
- /* FIXME this is made-up ... the correct value is known to
- * word-at-a-time bitbang code, and presumably chipselect()
- * should enforce these requirements too?
- */
- nsecs = 100;
+ spin_unlock_irqrestore(&bitbang->lock, flags);
- spi = m->spi;
- tmp = 0;
- cs_change = 1;
- status = 0;
+ /* FIXME this is made-up ... the correct value is known to
+ * word-at-a-time bitbang code, and presumably chipselect()
+ * should enforce these requirements too?
+ */
+ nsecs = 100;
- list_for_each_entry (t, &m->transfers, transfer_list) {
-
- /* override speed or wordsize? */
- if (t->speed_hz || t->bits_per_word)
- do_setup = 1;
-
- /* init (-1) or override (1) transfer params */
- if (do_setup != 0) {
- status = bitbang->setup_transfer(spi, t);
- if (status < 0)
- break;
- if (do_setup == -1)
- do_setup = 0;
- }
-
- /* set up default clock polarity, and activate chip;
- * this implicitly updates clock and spi modes as
- * previously recorded for this device via setup().
- * (and also deselects any other chip that might be
- * selected ...)
- */
- if (cs_change) {
- bitbang->chipselect(spi, BITBANG_CS_ACTIVE);
- ndelay(nsecs);
- }
- cs_change = t->cs_change;
- if (!t->tx_buf && !t->rx_buf && t->len) {
- status = -EINVAL;
- break;
- }
+ cs_change = 1;
+ status = 0;
- /* transfer data. the lower level code handles any
- * new dma mappings it needs. our caller always gave
- * us dma-safe buffers.
- */
- if (t->len) {
- /* REVISIT dma API still needs a designated
- * DMA_ADDR_INVALID; ~0 might be better.
- */
- if (!m->is_dma_mapped)
- t->rx_dma = t->tx_dma = 0;
- status = bitbang->txrx_bufs(spi, t);
- }
- if (status > 0)
- m->actual_length += status;
- if (status != t->len) {
- /* always report some kind of error */
- if (status >= 0)
- status = -EREMOTEIO;
+ list_for_each_entry (t, &msg->transfers, transfer_list) {
+
+ /* override speed or wordsize? */
+ if (t->speed_hz || t->bits_per_word)
+ do_setup = 1;
+
+ /* init (-1) or override (1) transfer params */
+ if (do_setup != 0) {
+ status = bitbang->setup_transfer(spi, t);
+ if (status < 0)
break;
- }
- status = 0;
-
- /* protocol tweaks before next transfer */
- if (t->delay_usecs)
- udelay(t->delay_usecs);
-
- if (cs_change && !list_is_last(&t->transfer_list,
&m->transfers)) {
- /* sometimes a short mid-message deselect of
the chip
- * may be needed to terminate a mode or command
- */
- ndelay(nsecs);
- bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
- ndelay(nsecs);
- }
+ if (do_setup == -1)
+ do_setup = 0;
}
- m->status = status;
- m->complete(m->context);
+ /* set up default clock polarity, and activate chip;
+ * this implicitly updates clock and spi modes as
+ * previously recorded for this device via setup().
+ * (and also deselects any other chip that might be
+ * selected ...)
+ */
+ if (cs_change) {
+ bitbang->chipselect(spi, BITBANG_CS_ACTIVE);
+ ndelay(nsecs);
+ }
+ cs_change = t->cs_change;
+ if (!t->tx_buf && !t->rx_buf && t->len) {
+ status = -EINVAL;
+ break;
+ }
- /* normally deactivate chipselect ... unless no error and
- * cs_change has hinted that the next message will probably
- * be for this chip too.
+ /* transfer data. the lower level code handles any
+ * new dma mappings it needs. our caller always gave
+ * us dma-safe buffers.
*/
- if (!(status == 0 && cs_change) ||
- spi->flags & SPI_BOARD_FLAG_RELEASE_CS) {
+ if (t->len) {
+ /* REVISIT dma API still needs a designated
+ * DMA_ADDR_INVALID; ~0 might be better.
+ */
+ if (!msg->is_dma_mapped)
+ t->rx_dma = t->tx_dma = 0;
+ status = bitbang->txrx_bufs(spi, t);
+ }
+ if (status > 0)
+ msg->actual_length += status;
+ if (status != t->len) {
+ /* always report some kind of error */
+ if (status >= 0)
+ status = -EREMOTEIO;
+ break;
+ }
+ status = 0;
+
+ /* protocol tweaks before next transfer */
+ if (t->delay_usecs)
+ udelay(t->delay_usecs);
+
+ if (cs_change && !list_is_last(&t->transfer_list,
&msg->transfers)) {
+ /* sometimes a short mid-message deselect of the chip
+ * may be needed to terminate a mode or command
+ */
ndelay(nsecs);
bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
ndelay(nsecs);
}
-
- spin_lock_irqsave(&bitbang->lock, flags);
}
- bitbang->busy = 0;
- spin_unlock_irqrestore(&bitbang->lock, flags);
-}
-/**
- * spi_bitbang_transfer - default submit to transfer queue
- */
-int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m)
-{
- struct spi_bitbang *bitbang;
- unsigned long flags;
- int status = 0;
-
- m->actual_length = 0;
- m->status = -EINPROGRESS;
+ msg->status = status;
- bitbang = spi_master_get_devdata(spi->master);
+ /* normally deactivate chipselect ... unless no error and
+ * cs_change has hinted that the next message will probably
+ * be for this chip too.
+ */
+ if (!(status == 0 && cs_change) ||
+ spi->flags & SPI_BOARD_FLAG_RELEASE_CS) {
+ ndelay(nsecs);
+ bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
+ ndelay(nsecs);
+ }
spin_lock_irqsave(&bitbang->lock, flags);
- if (!spi->max_speed_hz)
- status = -ENETDOWN;
- else {
- list_add_tail(&m->queue, &bitbang->queue);
- queue_work(bitbang->workqueue, &bitbang->work);
- }
+ bitbang->busy = 0;
spin_unlock_irqrestore(&bitbang->lock, flags);
- return status;
+ spi_finalize_current_message(master);
+
+ return 0;
+}
+
+static int spi_bitbang_dummy_prepare(struct spi_master *master)
+{
+ return 0;
}
-EXPORT_SYMBOL_GPL(spi_bitbang_transfer);
/*----------------------------------------------------------------------*/
@@ -408,9 +371,7 @@ EXPORT_SYMBOL_GPL(spi_bitbang_transfer);
* @bitbang: driver handle
*
* Caller should have zero-initialized all parts of the structure, and then
- * provided callbacks for chip selection and I/O loops. If the master has
- * a transfer method, its final step should call spi_bitbang_transfer; or,
- * that's the default if the transfer routine is not initialized. It should
+ * provided callbacks for chip selection and I/O loops. It should
* also set up the bus number and number of chipselects.
*
* For i/o loops, provide callbacks either per-word (for bitbanging, or for
@@ -428,58 +389,37 @@ EXPORT_SYMBOL_GPL(spi_bitbang_transfer);
*/
int spi_bitbang_start(struct spi_bitbang *bitbang)
{
- int status;
+ struct spi_master *master = bitbang->master;
- if (!bitbang->master || !bitbang->chipselect)
+ if (!master || !bitbang->chipselect)
return -EINVAL;
- INIT_WORK(&bitbang->work, bitbang_work);
spin_lock_init(&bitbang->lock);
- INIT_LIST_HEAD(&bitbang->queue);
- if (!bitbang->master->mode_bits)
- bitbang->master->mode_bits = SPI_CPOL | SPI_CPHA |
bitbang->flags;
+ if (!master->mode_bits)
+ master->mode_bits = SPI_CPOL | SPI_CPHA | bitbang->flags;
+
+ master->transfer_one_message = spi_bitbang_transfer_one_message;
+ master->prepare_transfer_hardware = spi_bitbang_dummy_prepare;
+ master->unprepare_transfer_hardware = spi_bitbang_dummy_prepare;
- if (!bitbang->master->transfer)
- bitbang->master->transfer = spi_bitbang_transfer;
if (!bitbang->txrx_bufs) {
bitbang->use_dma = 0;
bitbang->txrx_bufs = spi_bitbang_bufs;
- if (!bitbang->master->setup) {
+ if (!master->setup) {
if (!bitbang->setup_transfer)
bitbang->setup_transfer =
spi_bitbang_setup_transfer;
- bitbang->master->setup = spi_bitbang_setup;
- bitbang->master->cleanup = spi_bitbang_cleanup;
+ master->setup = spi_bitbang_setup;
+ master->cleanup = spi_bitbang_cleanup;
}
- } else if (!bitbang->master->setup)
- return -EINVAL;
- if (bitbang->master->transfer == spi_bitbang_transfer &&
- !bitbang->setup_transfer)
+ } else if (!master->setup)
return -EINVAL;
- /* this task is the only thing to touch the SPI bits */
- bitbang->busy = 0;
- bitbang->workqueue = create_singlethread_workqueue(
- dev_name(bitbang->master->dev.parent));
- if (bitbang->workqueue == NULL) {
- status = -EBUSY;
- goto err1;
- }
-
/* driver may get busy before register() returns, especially
* if someone registered boardinfo for devices
*/
- status = spi_register_master(bitbang->master);
- if (status < 0)
- goto err2;
-
- return status;
-
-err2:
- destroy_workqueue(bitbang->workqueue);
-err1:
- return status;
+ return spi_register_master(master);
}
EXPORT_SYMBOL_GPL(spi_bitbang_start);
@@ -490,10 +430,6 @@ int spi_bitbang_stop(struct spi_bitbang *bitbang)
{
spi_unregister_master(bitbang->master);
- WARN_ON(!list_empty(&bitbang->queue));
-
- destroy_workqueue(bitbang->workqueue);
-
return 0;
}
EXPORT_SYMBOL_GPL(spi_bitbang_stop);
diff --git a/include/linux/spi/spi_bitbang.h b/include/linux/spi/spi_bitbang.h
index f987a2b..f85a7b8 100644
--- a/include/linux/spi/spi_bitbang.h
+++ b/include/linux/spi/spi_bitbang.h
@@ -1,14 +1,8 @@
#ifndef __SPI_BITBANG_H
#define __SPI_BITBANG_H
-#include <linux/workqueue.h>
-
struct spi_bitbang {
- struct workqueue_struct *workqueue;
- struct work_struct work;
-
spinlock_t lock;
- struct list_head queue;
u8 busy;
u8 use_dma;
u8 flags; /* extra spi->mode support */
@@ -41,7 +35,6 @@ struct spi_bitbang {
*/
extern int spi_bitbang_setup(struct spi_device *spi);
extern void spi_bitbang_cleanup(struct spi_device *spi);
-extern int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m);
extern int spi_bitbang_setup_transfer(struct spi_device *spi,
struct spi_transfer *t);
--
1.7.2.5
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