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authorRafał Miłecki <zajec5@gmail.com>2016-04-26 09:23:12 +0000
committerRafał Miłecki <zajec5@gmail.com>2016-04-26 09:23:12 +0000
commit83ca0efb3e1e5b765d8b8a6bcb2e681f51b7a944 (patch)
treee1090642ca777f9c40bb4b0911586407ccf1ebe1 /target/linux/generic/patches-4.4/080-spi-introduce-accelerated-read-support-for-spi-flash.patch
parente53d533a24552128a0b63fe4ecbdfb2be6a78e37 (diff)
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kernel: backport support for accelerated SPI flash read
Signed-off-by: Rafał Miłecki <zajec5@gmail.com> SVN-Revision: 49233
Diffstat (limited to 'target/linux/generic/patches-4.4/080-spi-introduce-accelerated-read-support-for-spi-flash.patch')
-rw-r--r--target/linux/generic/patches-4.4/080-spi-introduce-accelerated-read-support-for-spi-flash.patch179
1 files changed, 179 insertions, 0 deletions
diff --git a/target/linux/generic/patches-4.4/080-spi-introduce-accelerated-read-support-for-spi-flash.patch b/target/linux/generic/patches-4.4/080-spi-introduce-accelerated-read-support-for-spi-flash.patch
new file mode 100644
index 0000000..5e116b0
--- /dev/null
+++ b/target/linux/generic/patches-4.4/080-spi-introduce-accelerated-read-support-for-spi-flash.patch
@@ -0,0 +1,179 @@
+From 556351f14e74db4cd3ddde386457edce7bf0b27f Mon Sep 17 00:00:00 2001
+From: Vignesh R <vigneshr@ti.com>
+Date: Fri, 11 Dec 2015 09:39:56 +0530
+Subject: [PATCH] spi: introduce accelerated read support for spi flash devices
+
+In addition to providing direct access to SPI bus, some spi controller
+hardwares (like ti-qspi) provide special port (like memory mapped port)
+that are optimized to improve SPI flash read performance.
+This means the controller can automatically send the SPI signals
+required to read data from the SPI flash device.
+For this, SPI controller needs to know flash specific information like
+read command to use, dummy bytes and address width.
+
+Introduce spi_flash_read() interface to support accelerated read
+over SPI flash devices. SPI master drivers can implement this callback to
+support interfaces such as memory mapped read etc. m25p80 flash driver
+and other flash drivers can call this make use of such interfaces. The
+interface should only be used with SPI flashes and cannot be used with
+other SPI devices.
+
+Signed-off-by: Vignesh R <vigneshr@ti.com>
+Signed-off-by: Mark Brown <broonie@kernel.org>
+---
+
+--- a/drivers/spi/spi.c
++++ b/drivers/spi/spi.c
+@@ -1135,6 +1135,7 @@ static void __spi_pump_messages(struct s
+ }
+ }
+
++ mutex_lock(&master->bus_lock_mutex);
+ trace_spi_message_start(master->cur_msg);
+
+ if (master->prepare_message) {
+@@ -1144,6 +1145,7 @@ static void __spi_pump_messages(struct s
+ "failed to prepare message: %d\n", ret);
+ master->cur_msg->status = ret;
+ spi_finalize_current_message(master);
++ mutex_unlock(&master->bus_lock_mutex);
+ return;
+ }
+ master->cur_msg_prepared = true;
+@@ -1153,6 +1155,7 @@ static void __spi_pump_messages(struct s
+ if (ret) {
+ master->cur_msg->status = ret;
+ spi_finalize_current_message(master);
++ mutex_unlock(&master->bus_lock_mutex);
+ return;
+ }
+
+@@ -1160,8 +1163,10 @@ static void __spi_pump_messages(struct s
+ if (ret) {
+ dev_err(&master->dev,
+ "failed to transfer one message from queue\n");
++ mutex_unlock(&master->bus_lock_mutex);
+ return;
+ }
++ mutex_unlock(&master->bus_lock_mutex);
+ }
+
+ /**
+@@ -2329,6 +2334,46 @@ int spi_async_locked(struct spi_device *
+ EXPORT_SYMBOL_GPL(spi_async_locked);
+
+
++int spi_flash_read(struct spi_device *spi,
++ struct spi_flash_read_message *msg)
++
++{
++ struct spi_master *master = spi->master;
++ int ret;
++
++ if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
++ msg->addr_nbits == SPI_NBITS_DUAL) &&
++ !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
++ return -EINVAL;
++ if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
++ msg->addr_nbits == SPI_NBITS_QUAD) &&
++ !(spi->mode & SPI_TX_QUAD))
++ return -EINVAL;
++ if (msg->data_nbits == SPI_NBITS_DUAL &&
++ !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
++ return -EINVAL;
++ if (msg->data_nbits == SPI_NBITS_QUAD &&
++ !(spi->mode & SPI_RX_QUAD))
++ return -EINVAL;
++
++ if (master->auto_runtime_pm) {
++ ret = pm_runtime_get_sync(master->dev.parent);
++ if (ret < 0) {
++ dev_err(&master->dev, "Failed to power device: %d\n",
++ ret);
++ return ret;
++ }
++ }
++ mutex_lock(&master->bus_lock_mutex);
++ ret = master->spi_flash_read(spi, msg);
++ mutex_unlock(&master->bus_lock_mutex);
++ if (master->auto_runtime_pm)
++ pm_runtime_put(master->dev.parent);
++
++ return ret;
++}
++EXPORT_SYMBOL_GPL(spi_flash_read);
++
+ /*-------------------------------------------------------------------------*/
+
+ /* Utility methods for SPI master protocol drivers, layered on
+--- a/include/linux/spi/spi.h
++++ b/include/linux/spi/spi.h
+@@ -25,6 +25,7 @@
+ struct dma_chan;
+ struct spi_master;
+ struct spi_transfer;
++struct spi_flash_read_message;
+
+ /*
+ * INTERFACES between SPI master-side drivers and SPI infrastructure.
+@@ -361,6 +362,8 @@ static inline void spi_unregister_driver
+ * @handle_err: the subsystem calls the driver to handle an error that occurs
+ * in the generic implementation of transfer_one_message().
+ * @unprepare_message: undo any work done by prepare_message().
++ * @spi_flash_read: to support spi-controller hardwares that provide
++ * accelerated interface to read from flash devices.
+ * @cs_gpios: Array of GPIOs to use as chip select lines; one per CS
+ * number. Any individual value may be -ENOENT for CS lines that
+ * are not GPIOs (driven by the SPI controller itself).
+@@ -507,6 +510,8 @@ struct spi_master {
+ struct spi_message *message);
+ int (*unprepare_message)(struct spi_master *master,
+ struct spi_message *message);
++ int (*spi_flash_read)(struct spi_device *spi,
++ struct spi_flash_read_message *msg);
+
+ /*
+ * These hooks are for drivers that use a generic implementation
+@@ -999,6 +1004,42 @@ static inline ssize_t spi_w8r16be(struct
+ return be16_to_cpu(result);
+ }
+
++/**
++ * struct spi_flash_read_message - flash specific information for
++ * spi-masters that provide accelerated flash read interfaces
++ * @buf: buffer to read data
++ * @from: offset within the flash from where data is to be read
++ * @len: length of data to be read
++ * @retlen: actual length of data read
++ * @read_opcode: read_opcode to be used to communicate with flash
++ * @addr_width: number of address bytes
++ * @dummy_bytes: number of dummy bytes
++ * @opcode_nbits: number of lines to send opcode
++ * @addr_nbits: number of lines to send address
++ * @data_nbits: number of lines for data
++ */
++struct spi_flash_read_message {
++ void *buf;
++ loff_t from;
++ size_t len;
++ size_t retlen;
++ u8 read_opcode;
++ u8 addr_width;
++ u8 dummy_bytes;
++ u8 opcode_nbits;
++ u8 addr_nbits;
++ u8 data_nbits;
++};
++
++/* SPI core interface for flash read support */
++static inline bool spi_flash_read_supported(struct spi_device *spi)
++{
++ return spi->master->spi_flash_read ? true : false;
++}
++
++int spi_flash_read(struct spi_device *spi,
++ struct spi_flash_read_message *msg);
++
+ /*---------------------------------------------------------------------------*/
+
+ /*