ar71xx: improve SPI flash read/write performance

[openwrt/staging/mkresin.git] / target / linux / ar71xx / patches-3.3 / 201-spi-ath79-add-delay-between-SCK-changes.patch

diff --git a/target/linux/ar71xx/patches-3.3/201-spi-ath79-add-delay-between-SCK-changes.patch b/target/linux/ar71xx/patches-3.3/201-spi-ath79-add-delay-between-SCK-changes.patch
index c2681f9a5dbd8c6c83933b7eaa853c6ccbee0629..9294133d456fa2173c7f7f38f39e63fd2db2ba5a 100644 (file)
--- a/target/linux/ar71xx/patches-3.3/201-spi-ath79-add-delay-between-SCK-changes.patch
+++ b/target/linux/ar71xx/patches-3.3/201-spi-ath79-add-delay-between-SCK-changes.patch
@@ -1,4 +1,4 @@
-From 48b7e765e6e097d20d809fadd17a4355d26ad6d5 Mon Sep 17 00:00:00 2001
+From 8e948c035dd7983eccc3a889f2497e64044f3a31 Mon Sep 17 00:00:00 2001
 From: Gabor Juhos <juhosg@openwrt.org>
 Date: Wed, 11 Jan 2012 20:06:35 +0100
 Subject: [PATCH 1/7] spi/ath79: add delay between SCK changes
@@ -12,31 +12,111 @@ well.
 
 Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
 ---
- drivers/spi/spi-ath79.c |    8 ++++++++
- 1 files changed, 8 insertions(+), 0 deletions(-)
+ drivers/spi/spi-ath79.c |   44 +++++++++++++++++++++++++++++++++++++++++++-
+ 1 files changed, 43 insertions(+), 1 deletions(-)
 
 --- a/drivers/spi/spi-ath79.c
 +++ b/drivers/spi/spi-ath79.c
-@@ -52,6 +52,12 @@ static inline struct ath79_spi *ath79_sp
+@@ -24,17 +24,24 @@
+ #include <linux/spi/spi_bitbang.h>
+ #include <linux/bitops.h>
+ #include <linux/gpio.h>
++#include <linux/clk.h>
++#include <linux/err.h>
+ 
+ #include <asm/mach-ath79/ar71xx_regs.h>
+ #include <asm/mach-ath79/ath79_spi_platform.h>
+ 
+ #define DRV_NAME      "ath79-spi"
+ 
++#define ATH79_SPI_RRW_DELAY_FACTOR    12000
++#define MHZ                           (1000 * 1000)
++
+ struct ath79_spi {
+       struct spi_bitbang      bitbang;
+       u32                     ioc_base;
+       u32                     reg_ctrl;
+       void __iomem            *base;
++      struct clk              *clk;
++      unsigned                rrw_delay;
+ };
+ 
+ static inline u32 ath79_spi_rr(struct ath79_spi *sp, unsigned reg)
+@@ -52,6 +59,12 @@ static inline struct ath79_spi *ath79_sp
        return spi_master_get_devdata(spi->master);
  }
  
-+static inline void ath79_spi_delay(unsigned nsecs)
++static inline void ath79_spi_delay(struct ath79_spi *sp, unsigned nsecs)
 +{
-+      if (nsecs)
-+              ndelay(nsecs);
++      if (nsecs > sp->rrw_delay)
++              ndelay(nsecs - sp->rrw_delay);
 +}
 +
  static void ath79_spi_chipselect(struct spi_device *spi, int is_active)
  {
        struct ath79_spi *sp = ath79_spidev_to_sp(spi);
-@@ -184,7 +190,9 @@ static u32 ath79_spi_txrx_mode0(struct s
+@@ -184,7 +197,9 @@ static u32 ath79_spi_txrx_mode0(struct s
  
                /* setup MSB (to slave) on trailing edge */
                ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out);
-+              ath79_spi_delay(nsecs);
++              ath79_spi_delay(sp, nsecs);
                ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out | AR71XX_SPI_IOC_CLK);
-+              ath79_spi_delay(nsecs);
++              ath79_spi_delay(sp, nsecs);
  
                word <<= 1;
        }
+@@ -198,6 +213,7 @@ static __devinit int ath79_spi_probe(str
+       struct ath79_spi *sp;
+       struct ath79_spi_platform_data *pdata;
+       struct resource *r;
++      unsigned long rate;
+       int ret;
+ 
+       master = spi_alloc_master(&pdev->dev, sizeof(*sp));
+@@ -239,12 +255,36 @@ static __devinit int ath79_spi_probe(str
+               goto err_put_master;
+       }
+ 
++      sp->clk = clk_get(&pdev->dev, "ahb");
++      if (IS_ERR(sp->clk)) {
++              ret = PTR_ERR(sp->clk);
++              goto err_unmap;
++      }
++
++      ret = clk_enable(sp->clk);
++      if (ret)
++              goto err_clk_put;
++
++      rate = DIV_ROUND_UP(clk_get_rate(sp->clk), MHZ);
++      if (!rate) {
++              ret = -EINVAL;
++              goto err_clk_disable;
++      }
++
++      sp->rrw_delay = ATH79_SPI_RRW_DELAY_FACTOR / rate;
++      dev_dbg(&pdev->dev, "register read/write delay is %u nsecs\n",
++              sp->rrw_delay);
++
+       ret = spi_bitbang_start(&sp->bitbang);
+       if (ret)
+-              goto err_unmap;
++              goto err_clk_disable;
+ 
+       return 0;
+ 
++err_clk_disable:
++      clk_disable(sp->clk);
++err_clk_put:
++      clk_put(sp->clk);
+ err_unmap:
+       iounmap(sp->base);
+ err_put_master:
+@@ -259,6 +299,8 @@ static __devexit int ath79_spi_remove(st
+       struct ath79_spi *sp = platform_get_drvdata(pdev);
+ 
+       spi_bitbang_stop(&sp->bitbang);
++      clk_disable(sp->clk);
++      clk_put(sp->clk);
+       iounmap(sp->base);
+       platform_set_drvdata(pdev, NULL);
+       spi_master_put(sp->bitbang.master);