kernel: backport support for accelerated SPI flash read

[openwrt/svn-archive/archive.git] / target / linux / generic / patches-4.4 / 081-spi-bcm53xx-add-spi_flash_read-callback-for-MMIO-bas.patch

diff --git a/target/linux/generic/patches-4.4/081-spi-bcm53xx-add-spi_flash_read-callback-for-MMIO-bas.patch b/target/linux/generic/patches-4.4/081-spi-bcm53xx-add-spi_flash_read-callback-for-MMIO-bas.patch
new file mode 100644 (file)
index 0000000..5f131e7
--- /dev/null
+++ b/target/linux/generic/patches-4.4/081-spi-bcm53xx-add-spi_flash_read-callback-for-MMIO-bas.patch
@@ -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);