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kernel: backport support for accelerated SPI flash read

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Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

SVN-Revision: 49233
This commit is contained in:
Rafał Miłecki 2016-04-26 09:23:12 +00:00
parent e53d533a24
commit 83ca0efb3e
3 changed files with 382 additions and 0 deletions
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46
target/linux/generic/patches-4.4/045-mtd-devices-m25p80-add-support-for-mmap-read-request.patch Normal file
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@ -0,0 +1,46 @@
From 08922f644878c9163ada8df3ef9def89be1d5e90 Mon Sep 17 00:00:00 2001
From: Vignesh R <vigneshr@ti.com>
Date: Tue, 29 Mar 2016 11:16:17 +0530
Subject: [PATCH] mtd: devices: m25p80: add support for mmap read request
Certain SPI controllers may provide accelerated hardware interface to
read from m25p80 type flash devices in order to provide better read
performance. SPI core supports such devices with spi_flash_read() API.
Call spi_flash_read(), if supported, to make use of such interface.
Signed-off-by: Vignesh R <vigneshr@ti.com>
[Brian: add memset()]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
---
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -131,6 +131,28 @@ static int m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
/* convert the dummy cycles to the number of bytes */
dummy /= 8;
+ if (spi_flash_read_supported(spi)) {
+ struct spi_flash_read_message msg;
+ int ret;
+
+ memset(&msg, 0, sizeof(msg));
+
+ msg.buf = buf;
+ msg.from = from;
+ msg.len = len;
+ msg.read_opcode = nor->read_opcode;
+ msg.addr_width = nor->addr_width;
+ msg.dummy_bytes = dummy;
+ /* TODO: Support other combinations */
+ msg.opcode_nbits = SPI_NBITS_SINGLE;
+ msg.addr_nbits = SPI_NBITS_SINGLE;
+ msg.data_nbits = m25p80_rx_nbits(nor);
+
+ ret = spi_flash_read(spi, &msg);
+ *retlen = msg.retlen;
+ return ret;
+ }
+
spi_message_init(&m);
memset(t, 0, (sizeof t));

179
target/linux/generic/patches-4.4/080-spi-introduce-accelerated-read-support-for-spi-flash.patch Normal file
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@ -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);
+
/*---------------------------------------------------------------------------*/
/*

157
target/linux/generic/patches-4.4/081-spi-bcm53xx-add-spi_flash_read-callback-for-MMIO-bas.patch Normal file
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@ -0,0 +1,157 @@
From a7b221d8f0d75511c5f959584712a5dd35f88a86 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>
Date: Mon, 18 Apr 2016 14:39:30 +0200
Subject: [PATCH] spi: bcm53xx: add spi_flash_read callback for MMIO-based
reads
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
This implements more efficient reads of SPI-attached flash content.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
--- a/drivers/spi/spi-bcm53xx.c
+++ b/drivers/spi/spi-bcm53xx.c
@@ -10,6 +10,7 @@
#include "spi-bcm53xx.h"
#define BCM53XXSPI_MAX_SPI_BAUD 13500000 /* 216 MHz? */
+#define BCM53XXSPI_FLASH_WINDOW SZ_32M
/* The longest observed required wait was 19 ms */
#define BCM53XXSPI_SPE_TIMEOUT_MS 80
@@ -17,8 +18,10 @@
struct bcm53xxspi {
struct bcma_device *core;
struct spi_master *master;
+ void __iomem *mmio_base;
size_t read_offset;
+ bool bspi; /* Boot SPI mode with memory mapping */
};
static inline u32 bcm53xxspi_read(struct bcm53xxspi *b53spi, u16 offset)
@@ -32,6 +35,50 @@ static inline void bcm53xxspi_write(struct bcm53xxspi *b53spi, u16 offset,
bcma_write32(b53spi->core, offset, value);
}
+static void bcm53xxspi_disable_bspi(struct bcm53xxspi *b53spi)
+{
+ struct device *dev = &b53spi->core->dev;
+ unsigned long deadline;
+ u32 tmp;
+
+ if (!b53spi->bspi)
+ return;
+
+ tmp = bcm53xxspi_read(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL);
+ if (tmp & 0x1)
+ return;
+
+ deadline = jiffies + usecs_to_jiffies(200);
+ do {
+ tmp = bcm53xxspi_read(b53spi, B53SPI_BSPI_BUSY_STATUS);
+ if (!(tmp & 0x1)) {
+ bcm53xxspi_write(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL,
+ 0x1);
+ ndelay(200);
+ b53spi->bspi = false;
+ return;
+ }
+ udelay(1);
+ } while (!time_after_eq(jiffies, deadline));
+
+ dev_warn(dev, "Timeout disabling BSPI\n");
+}
+
+static void bcm53xxspi_enable_bspi(struct bcm53xxspi *b53spi)
+{
+ u32 tmp;
+
+ if (b53spi->bspi)
+ return;
+
+ tmp = bcm53xxspi_read(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL);
+ if (!(tmp & 0x1))
+ return;
+
+ bcm53xxspi_write(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL, 0x0);
+ b53spi->bspi = true;
+}
+
static inline unsigned int bcm53xxspi_calc_timeout(size_t len)
{
/* Do some magic calculation based on length and buad. Add 10% and 1. */
@@ -176,6 +223,8 @@ static int bcm53xxspi_transfer_one(struct spi_master *master,
u8 *buf;
size_t left;
+ bcm53xxspi_disable_bspi(b53spi);
+
if (t->tx_buf) {
buf = (u8 *)t->tx_buf;
left = t->len;
@@ -206,6 +255,22 @@ static int bcm53xxspi_transfer_one(struct spi_master *master,
return 0;
}
+static int bcm53xxspi_flash_read(struct spi_device *spi,
+ struct spi_flash_read_message *msg)
+{
+ struct bcm53xxspi *b53spi = spi_master_get_devdata(spi->master);
+ int ret = 0;
+
+ if (msg->from + msg->len > BCM53XXSPI_FLASH_WINDOW)
+ return -EINVAL;
+
+ bcm53xxspi_enable_bspi(b53spi);
+ memcpy_fromio(msg->buf, b53spi->mmio_base + msg->from, msg->len);
+ msg->retlen = msg->len;
+
+ return ret;
+}
+
/**************************************************
* BCMA
**************************************************/
@@ -222,6 +287,7 @@ MODULE_DEVICE_TABLE(bcma, bcm53xxspi_bcma_tbl);
static int bcm53xxspi_bcma_probe(struct bcma_device *core)
{
+ struct device *dev = &core->dev;
struct bcm53xxspi *b53spi;
struct spi_master *master;
int err;
@@ -231,7 +297,7 @@ static int bcm53xxspi_bcma_probe(struct bcma_device *core)
return -ENOTSUPP;
}
- master = spi_alloc_master(&core->dev, sizeof(*b53spi));
+ master = spi_alloc_master(dev, sizeof(*b53spi));
if (!master)
return -ENOMEM;
@@ -239,11 +305,19 @@ static int bcm53xxspi_bcma_probe(struct bcma_device *core)
b53spi->master = master;
b53spi->core = core;
+ if (core->addr_s[0])
+ b53spi->mmio_base = devm_ioremap(dev, core->addr_s[0],
+ BCM53XXSPI_FLASH_WINDOW);
+ b53spi->bspi = true;
+ bcm53xxspi_disable_bspi(b53spi);
+
master->transfer_one = bcm53xxspi_transfer_one;
+ if (b53spi->mmio_base)
+ master->spi_flash_read = bcm53xxspi_flash_read;
bcma_set_drvdata(core, b53spi);
- err = devm_spi_register_master(&core->dev, master);
+ err = devm_spi_register_master(dev, master);
if (err) {
spi_master_put(master);
bcma_set_drvdata(core, NULL);