[haiku-commits] r35881 - haiku/trunk/src/system/boot/platform/bios_ia32

From: ingo_weinhold@xxxxxx
To: haiku-commits@xxxxxxxxxxxxx
Date: Tue, 16 Mar 2010 18:10:00 +0100 (CET)
Author: bonefish
Date: 2010-03-16 18:10:00 +0100 (Tue, 16 Mar 2010)
New Revision: 35881
Changeset: http://dev.haiku-os.org/changeset/35881/haiku

Modified:
   haiku/trunk/src/system/boot/platform/bios_ia32/devices.cpp
Log:
Implemented BIOSDrive::WriteAt(). Currently it supports only LBA addressing
and requires position and size to be block-aligned.


Modified: haiku/trunk/src/system/boot/platform/bios_ia32/devices.cpp
===================================================================
--- haiku/trunk/src/system/boot/platform/bios_ia32/devices.cpp  2010-03-16 
17:07:40 UTC (rev 35880)
+++ haiku/trunk/src/system/boot/platform/bios_ia32/devices.cpp  2010-03-16 
17:10:00 UTC (rev 35881)
@@ -33,6 +33,7 @@
 #define BIOS_GET_DRIVE_PARAMETERS              0x0800
 #define BIOS_IS_EXT_PRESENT                            0x4100
 #define BIOS_EXT_READ                                  0x4200
+#define BIOS_EXT_WRITE                                 0x4300
 #define BIOS_GET_EXT_DRIVE_PARAMETERS  0x4800
 #define BIOS_BOOT_CD_GET_STATUS                        0x4b01
 
@@ -531,7 +532,7 @@
        }
 
        sBlockDevicesAdded = true;
-       return B_OK; 
+       return B_OK;
 }
 
 
@@ -585,14 +586,14 @@
 }
 
 
-status_t 
+status_t
 BIOSDrive::InitCheck() const
 {
        return fSize > 0 ? B_OK : B_ERROR;
 }
 
 
-ssize_t 
+ssize_t
 BIOSDrive::ReadAt(void *cookie, off_t pos, void *buffer, size_t bufferSize)
 {
        uint32 offset = pos % fBlockSize;
@@ -706,15 +707,70 @@
 }
 
 
-ssize_t 
-BIOSDrive::WriteAt(void *cookie, off_t pos, const void *buffer, size_t 
bufferSize)
+ssize_t
+BIOSDrive::WriteAt(void* cookie, off_t pos, const void* buffer,
+       size_t bufferSize)
 {
-       // we don't have to know how to write
-       return B_NOT_ALLOWED;
+       // we support only LBA addressing
+       if (!fLBA) {
+               dprintf("BIOSDrive::WriteAt(): CHS addressing not supported\n");
+               return B_UNSUPPORTED;
+       }
+
+       // we support only block-aligned writes
+       if (pos % fBlockSize != 0 || bufferSize % fBlockSize != 0) {
+               dprintf("BIOSDrive::WriteAt(pos: %" B_PRIdOFF ", size: %" 
B_PRIuSIZE
+                       "): Block-unaligned write not supported.\n", pos, 
bufferSize);
+               return B_UNSUPPORTED;
+       }
+
+       pos /= fBlockSize;
+
+       uint32 blocksLeft = bufferSize / fBlockSize;
+       int32 totalBytesWritten = 0;
+
+       uint32 scratchSize = 24 * 1024 / fBlockSize;
+               // maximum value allowed by Phoenix BIOS is 0x7f
+
+       while (blocksLeft > 0) {
+               uint32 blocksToWrite = blocksLeft;
+               if (blocksToWrite > scratchSize)
+                       blocksToWrite = scratchSize;
+
+               uint32 bytesToWrite = blocksToWrite * fBlockSize;
+
+               memcpy((void*)kExtraSegmentScratch, buffer, bytesToWrite);
+
+               struct disk_address_packet* packet
+                       = (disk_address_packet*)kDataSegmentScratch;
+               memset(packet, 0, sizeof(disk_address_packet));
+
+               packet->size = sizeof(disk_address_packet);
+               packet->number_of_blocks = blocksToWrite;
+               packet->buffer = kExtraSegmentScratch;
+               packet->lba = pos;
+
+               struct bios_regs regs;
+               regs.eax = BIOS_EXT_WRITE;      // al = 0x00 -- no write verify
+               regs.edx = fDriveID;
+               regs.esi = (addr_t)packet - kDataSegmentBase;
+               call_bios(0x13, &regs);
+
+               if (regs.flags & CARRY_FLAG)
+                       return B_ERROR;
+
+               pos += blocksToWrite;
+               blocksLeft -= blocksToWrite;
+               bufferSize -= bytesToWrite;
+               buffer = (void*)((addr_t)buffer + bytesToWrite);
+               totalBytesWritten += bytesToWrite;
+       }
+
+       return totalBytesWritten;
 }
 
 
-off_t 
+off_t
 BIOSDrive::Size() const
 {
        return fSize;
@@ -763,7 +819,7 @@
 //     #pragma mark -
 
 
-status_t 
+status_t
 platform_add_boot_device(struct stage2_args *args, NodeList *devicesList)
 {
        TRACE(("boot drive ID: %x\n", gBootDriveID));
@@ -824,7 +880,7 @@
 }
 
 
-status_t 
+status_t
 platform_register_boot_device(Node *device)
 {
        BIOSDrive *drive = (BIOSDrive *)device;
[haiku-commits] r35881 - haiku/trunk/src/system/boot/platform/bios_ia32

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