From 9c7e10e5ff169a3ffb854b8023b103c9ef886ab8 Mon Sep 17 00:00:00 2001
From: batt <batt@38d2e660-2303-0410-9eaa-f027e97ec537>
Date: Thu, 8 Jul 2010 16:59:42 +0000
Subject: [PATCH] Increase read/write performances; add some comments.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@4015 38d2e660-2303-0410-9eaa-f027e97ec537
---
 bertos/drv/sd.c | 21 +++++++++++++++------
 bertos/drv/sd.h | 13 +++++++------
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/bertos/drv/sd.c b/bertos/drv/sd.c
index 9880dfe1..2b462b7b 100644
--- a/bertos/drv/sd.c
+++ b/bertos/drv/sd.c
@@ -243,10 +243,14 @@ static size_t sd_readDirect(struct KBlock *b, block_idx_t idx, void *buf, size_t
 	Sd *sd = SD_CAST(b);
 	LOG_INFO("reading from block %ld, offset %d, size %d\n", idx, offset, size);
 
-	if ((sd->r1 = sd_setBlockLen(sd, size)))
+	if (sd->tranfer_len != size)
 	{
-		LOG_ERR("setBlockLen failed: %04X\n", sd->r1);
-		return 0;
+		if ((sd->r1 = sd_setBlockLen(sd, size)))
+		{
+			LOG_ERR("setBlockLen failed: %04X\n", sd->r1);
+			return 0;
+		}
+		sd->tranfer_len = size;
 	}
 
 	SD_SELECT(sd);
@@ -280,10 +284,14 @@ static int sd_writeBlock(KBlock *b, block_idx_t idx, const void *buf)
 	KFile *fd = sd->ch;
 
 	LOG_INFO("writing block %ld\n", idx);
-	if ((sd->r1 = sd_setBlockLen(sd, SD_DEFAULT_BLOCKLEN)))
+	if (sd->tranfer_len != SD_DEFAULT_BLOCKLEN)
 	{
-		LOG_ERR("setBlockLen failed: %04X\n", sd->r1);
-		return sd->r1;
+		if ((sd->r1 = sd_setBlockLen(sd, SD_DEFAULT_BLOCKLEN)))
+		{
+			LOG_ERR("setBlockLen failed: %04X\n", sd->r1);
+			return sd->r1;
+		}
+		sd->tranfer_len = SD_DEFAULT_BLOCKLEN;
 	}
 
 	SD_SELECT(sd);
@@ -461,6 +469,7 @@ static bool sd_blockInit(Sd *sd, KFile *ch)
 	}
 
 	sd->r1 = sd_setBlockLen(sd, SD_DEFAULT_BLOCKLEN);
+	sd->tranfer_len = SD_DEFAULT_BLOCKLEN;
 
 	if (sd->r1)
 	{
diff --git a/bertos/drv/sd.h b/bertos/drv/sd.h
index 368e0d4f..9845fcb4 100644
--- a/bertos/drv/sd.h
+++ b/bertos/drv/sd.h
@@ -31,13 +31,11 @@
  *
  * \brief Function library for secure digital memory.
  *
- * Right now, the interface for these function is the one defined in diskio.h from
- * the FatFS module.
  *
  * \author Francesco Sacchi <batt@develer.com>
  *
  * $WIZ$ module_name = "sd"
- * $WIZ$ module_depends = "kfile", "timer"
+ * $WIZ$ module_depends = "kfile", "timer", "kblock"
  * $WIZ$ module_hw = "bertos/hw/hw_sd.h"
  * $WIZ$ module_configuration = "bertos/cfg/cfg_sd.h"
  */
@@ -53,12 +51,15 @@
 
 #include "cfg/cfg_sd.h"
 
-
+/**
+ * SD Card context structure.
+ */
 typedef struct Sd
 {
-	KBlock b;
+	KBlock b;   ///< KBlock base class
 	KFile *ch;  ///< SPI communication channel
-	uint16_t r1;
+	uint16_t r1;  ///< Last status data received from SD
+	uint16_t tranfer_len; ///< Lenght for the read/write commands, cached in order to increase speed.
 } Sd;
 
 bool sd_initUnbuf(Sd *sd, KFile *ch);
-- 
2.25.1