Attachment 728075 Details for Bug 1043231

[patch] 0017-spi-expose-master-transfer-size-limitation.patch

0017-spi-expose-master-transfer-size-limitation.patch (text/plain), 2.00 KB, created by Matwey Kornilov on 2017-06-07 19:37:50 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Matwey Kornilov

Created: 2017-06-07 19:37:50 UTC

Size: 2.00 KB

patch

obsolete

>From d8bc7d596514a9e63404cf6e6caa39f605e792df Mon Sep 17 00:00:00 2001
>From: Michal Suchanek <hramrach@gmail.com>
>Date: Wed, 2 Dec 2015 10:38:21 +0000
>Subject: [PATCH 17/19] spi: expose master transfer size limitation.
>
>On some SPI controllers it is not feasible to transfer arbitrary amount
>of data at once.
>
>When the limit on transfer size is a few kilobytes at least it makes
>sense to use the SPI hardware rather than reverting to gpio driver.
>
>The protocol drivers need a way to check that they do not sent overly
>long messages, though.
>
>Signed-off-by: Michal Suchanek <hramrach@gmail.com>
>Signed-off-by: Mark Brown <broonie@kernel.org>
>Git-commit: 4acad4aae10d1fa79a075b38b5c73772c44f576c
>Patch-mainline: v4.5-rc1
>Signed-off-by: Matwey V. Kornilov <matwey.kornilov@gmail.com>
>---
> include/linux/spi/spi.h | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
>diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
>index cce80e6dc7d1..3eebc6c235fb 100644
>--- a/include/linux/spi/spi.h
>+++ b/include/linux/spi/spi.h
>@@ -425,6 +425,12 @@ struct spi_master {
> #define SPI_MASTER_MUST_RX      BIT(3)		/* requires rx */
> #define SPI_MASTER_MUST_TX      BIT(4)		/* requires tx */
> 
>+	/*
>+	 * on some hardware transfer size may be constrained
>+	 * the limit may depend on device transfer settings
>+	 */
>+	size_t (*max_transfer_size)(struct spi_device *spi);
>+
> 	/* lock and mutex for SPI bus locking */
> 	spinlock_t		bus_lock_spinlock;
> 	struct mutex		bus_lock_mutex;
>@@ -832,6 +838,15 @@ extern int spi_async(struct spi_device *spi, struct spi_message *message);
> extern int spi_async_locked(struct spi_device *spi,
> 			    struct spi_message *message);
> 
>+static inline size_t
>+spi_max_transfer_size(struct spi_device *spi)
>+{
>+	struct spi_master *master = spi->master;
>+	if (!master->max_transfer_size)
>+		return SIZE_MAX;
>+	return master->max_transfer_size(spi);
>+}
>+
> /*---------------------------------------------------------------------------*/
> 
> /* All these synchronous SPI transfer routines are utilities layered
>-- 
>2.12.0
>

Actions: View | Diff

Attachments on bug 1043231: 728059 | 728060 | 728061 | 728062 | 728063 | 728064 | 728065 | 728066 | 728067 | 728068 | 728069 | 728070 | 728071 | 728072 | 728073 | 728074 | 728075 | 728076 | 728077 | 728521 | 728695 | 728770