Index: firmware/export/config-ipodvideo.h
===================================================================
--- firmware/export/config-ipodvideo.h	(revision 23773)
+++ firmware/export/config-ipodvideo.h	(working copy)
@@ -220,3 +220,5 @@
 #define IPOD_ACCESSORY_PROTOCOL
 #define HAVE_SERIAL
 
+/* Define this to add support for ATA DMA */
+#define HAVE_ATA_DMA
Index: firmware/target/arm/ata-target.h
===================================================================
--- firmware/target/arm/ata-target.h	(revision 23943)
+++ firmware/target/arm/ata-target.h	(working copy)
@@ -81,3 +81,29 @@
 void ata_reset(void);
 bool ata_is_coldstart(void);
 void ata_device_init(void);
+
+#ifdef HAVE_ATA_DMA
+
+/* IDE DMA controller registers */
+#define IDE_DMA_CONTROL (*(volatile unsigned long *)(0xc3000400))
+#define IDE_DMA_LENGTH  (*(volatile unsigned long *)(0xc3000408))
+#define IDE_DMA_ADDR    (*(volatile unsigned long *)(0xc300040C))
+
+/* Maximum multi-word DMA mode supported by the controller */
+#define ATA_MAX_MWDMA 2
+
+#ifndef BOOTLOADER    
+/* The PP5020 supports UDMA 4, but it needs cpu boosting and doesn't
+   improve test_disk results.  UDMA 2 is stable at 30 Mhz.
+ */
+#define ATA_MAX_UDMA 4
+#else
+/* The bootloader runs at 24 Mhz and needs a slower mode */
+#define ATA_MAX_UDMA 1
+#endif
+
+void ata_dma_set_mode(unsigned char mode);
+bool ata_dma_setup(void *addr, unsigned long bytes, bool write);
+bool ata_dma_finish(void);
+
+#endif /* HAVE_ATA_DMA */
Index: firmware/target/arm/ata-pp5020.c
===================================================================
--- firmware/target/arm/ata-pp5020.c	(revision 23943)
+++ firmware/target/arm/ata-pp5020.c	(working copy)
@@ -25,6 +25,9 @@
 #include "system.h"
 #include "ata.h"
 #include "ata-target.h"
+#ifdef HAVE_ATA_DMA
+#include "ata.h"
+#endif
 
 void ata_reset() 
 {
@@ -48,6 +51,13 @@
 #ifdef SAMSUNG_YH920
     CPU_INT_DIS = (1<<IDE_IRQ);
 #endif
+#ifdef HAVE_ATA_DMA
+    /* TODO: Is it necessary to wait for ready here? */
+    IDE_DMA_CONTROL |= 2;
+    IDE_DMA_CONTROL &= ~1;
+    IDE0_CFG &= ~0x8010;
+    IDE0_CFG |= 0x20; 
+#else
 
     /* From ipod-ide.c:ipod_ide_register() */
     IDE0_CFG |= (1<<5);
@@ -56,7 +66,175 @@
 #else
     IDE0_CFG &=~(0x10000000); /* cpu < 65MHz */
 #endif
+#endif
 
     IDE0_PRI_TIMING0 = 0x10;
     IDE0_PRI_TIMING1 = 0x80002150;
 }
+
+/* These are PIO timings for 80 Mhz.  At 24 Mhz, 
+   the first value is 0 but the rest are the same.
+   They go in IDE0_PRI_TIMING0.
+   
+   Rockbox used 0x10, and test_disk shows that leads to faster PIO.   
+   If 0x10 is incorrect, these timings may be needed with some devices.
+static const unsigned long pio80mhz[] = {
+    0xC293, 0x43A2, 0x11A1, 0x7232, 0x3131
+}; 
+*/
+
+#ifdef HAVE_ATA_DMA
+/* Timings for multi-word and ultra DMA modes.
+   These go in IDE0_PRI_TIMING1
+ */
+static const unsigned long tm_mwdma[] = {
+    0xF9F92, 0x56562, 0x45451 
+};
+
+static const unsigned long tm_udma[] = { 
+    0x800037C1, 0x80003491, 0x80003371, 
+#if ATA_MAX_UDMA > 2       
+    0x80003271, 0x80003071 
+#endif
+};
+
+#if ATA_MAX_UDMA > 2
+static bool dma_boosted = false;
+static bool dma_needs_boost;
+#endif
+
+/* This function sets up registers for 80 Mhz.
+   Ultra DMA mode 2 works at 30 Mhz.
+ */
+void ata_dma_set_mode(unsigned char mode) {
+    int modeidx;
+
+    (*(volatile unsigned long *)(0x600060C4)) = 0xC0000000; /* 80 Mhz */
+    IDE0_CFG &= ~0x10000000;
+
+    modeidx = mode & 7;
+    mode &= 0xF8;
+    if (mode == 0x40 && modeidx <= ATA_MAX_UDMA) {
+        IDE0_PRI_TIMING1 = tm_udma[modeidx];
+#if ATA_MAX_UDMA > 2
+        if (modeidx > 2)
+            dma_needs_boost = true;
+        else
+            dma_needs_boost = false;
+#endif
+    } else if (mode == 0x20 && modeidx <= ATA_MAX_MWDMA)
+        IDE0_PRI_TIMING1 = tm_mwdma[modeidx];
+
+    IDE0_CFG |= 0x20000000; /* >= 50 Mhz */
+} 
+
+#define IDE_CFG_INTRQ           8
+#define IDE_DMA_CONTROL_READ    8
+
+/* This waits for an ATA interrupt using polling.
+   In ATA_CONTROL, CONTROL_nIEN must be cleared.
+ */
+STATICIRAM ICODE_ATTR int ata_wait_intrq(void)
+{
+    long timeout = current_tick + HZ*10;
+    
+    do 
+    {
+        if (IDE0_CFG & IDE_CFG_INTRQ)
+            return 1;
+        ata_keep_active();
+        yield();
+    } while (TIME_BEFORE(current_tick, timeout));
+
+    return 0; /* timeout */
+}
+
+/* This function checks if parameters are appropriate for DMA, 
+   and if they are, it sets up for DMA.
+   
+   If return value is false, caller may use PIO for this transfer.
+   
+   If return value is true, caller must issue a DMA ATA command
+   and then call ata_dma_finish().
+ */
+bool ata_dma_setup(void *addr, unsigned long bytes, bool write) {
+    if ((unsigned long)addr & 3)
+        return false;
+    /* Require cacheline alignment for reads to prevent interference */
+    if (!write && ((unsigned long)addr & 15))
+        return false;
+
+#if ATA_MAX_UDMA > 2
+    if (dma_needs_boost && !dma_boosted) {
+        cpu_boost(true);
+        dma_boosted = true;
+    }
+#endif
+
+    if (write) {
+        /* If unflushed, old data may be written to disk */
+        cpucache_flush();
+    }
+    else {
+        /* Invalidate cache because new data may be present in RAM */
+        cpucache_invalidate();
+    }
+
+    /* Clear pending interrupts so ata_dma_finish() can wait for an
+       interrupt from this transfer
+     */
+    IDE0_CFG |= IDE_CFG_INTRQ;
+
+    IDE_DMA_CONTROL |= 2;
+    IDE_DMA_LENGTH = bytes - 4;
+
+#ifndef BOOTLOADER
+    if ((unsigned long)addr < DRAM_START)
+        /* Rockbox remaps DRAM to start at 0 */
+        IDE_DMA_ADDR = (unsigned long)addr + DRAM_START;
+    else
+#endif
+        IDE_DMA_ADDR = (unsigned long)addr;
+
+    if (write)
+        IDE_DMA_CONTROL &= ~IDE_DMA_CONTROL_READ;
+    else
+        IDE_DMA_CONTROL |= IDE_DMA_CONTROL_READ;
+
+    IDE0_CFG |= 0x8000;
+
+    return true;
+}
+
+/* This function waits for a DMA transfer to end.
+   It must be called to finish what ata_dma_setup started.
+   
+   Return value is true if DMA completed before the timeout, and false
+   if a timeout happened.
+ */
+bool ata_dma_finish(void) {
+    bool res;
+    
+    /* It may be okay to put this at the end of setup */
+    IDE_DMA_CONTROL |= 1;
+
+    /* Wait for end of transfer.
+       Reading standard ATA status while DMA is in progress causes 
+       failures and hangs.  Because of that, another wait is used.
+     */
+    res = ata_wait_intrq();
+
+    IDE0_CFG &= ~0x8000;
+    IDE_DMA_CONTROL &= ~0x80000001;
+
+#if ATA_MAX_UDMA > 2
+    if (dma_boosted) {
+        cpu_boost(false);
+        dma_boosted = false;
+    }
+#endif
+
+    return res;
+}
+
+#endif /* HAVE_ATA_DMA */