ide: cleanup ide_build_dmatable() (14c123f3) · Commits · 戴 / test

drivers/ide/ide-dma.c

+30 −43

Original line number	Diff line number	Diff line
		@@ -153,8 +153,11 @@ EXPORT_SYMBOL_GPL(ide_build_sglist);
		*
		* ide_build_dmatable() prepares a dma request. We map the command
		* to get the pci bus addresses of the buffers and then build up
		* the PRD table that the IDE layer wants to be fed. The code
		* knows about the 64K wrap bug in the CS5530.
		* the PRD table that the IDE layer wants to be fed.
		*
		* Most chipsets correctly interpret a length of 0x0000 as 64KB,
		* but at least one (e.g. CS5530) misinterprets it as zero (!).
		* So we break the 64KB entry into two 32KB entries instead.
		*
		* Returns the number of built PRD entries if all went okay,
		* returns 0 otherwise.
		@@ -171,15 +174,12 @@ int ide_build_dmatable (ide_drive_t drive, struct request rq)
		int i;
		struct scatterlist *sg;

		hwif->sg_nents = i = ide_build_sglist(drive, rq);

		if (!i)
		hwif->sg_nents = ide_build_sglist(drive, rq);
		if (hwif->sg_nents == 0)
		return 0;

		sg = hwif->sg_table;
		while (i) {
		u32 cur_addr;
		u32 cur_len;
		for_each_sg(hwif->sg_table, sg, hwif->sg_nents, i) {
		u32 cur_addr, cur_len, xcount, bcount;

		cur_addr = sg_dma_address(sg);
		cur_len = sg_dma_len(sg);
		@@ -191,28 +191,19 @@ int ide_build_dmatable (ide_drive_t drive, struct request rq)
		*/

		while (cur_len) {
		if (count++ >= PRD_ENTRIES) {
		printk(KERN_ERR "%s: DMA table too small\n", drive->name);
		if (count++ >= PRD_ENTRIES)
		goto use_pio_instead;
		} else {
		u32 xcount, bcount = 0x10000 - (cur_addr & 0xffff);

		bcount = 0x10000 - (cur_addr & 0xffff);
		if (bcount > cur_len)
		bcount = cur_len;
		*table++ = cpu_to_le32(cur_addr);
		xcount = bcount & 0xffff;
		if (is_trm290)
		xcount = ((xcount >> 2) - 1) << 16;
		else if (xcount == 0x0000) {
		/*
		* Most chipsets correctly interpret a length of 0x0000 as 64KB,
		* but at least one (e.g. CS5530) misinterprets it as zero (!).
		* So here we break the 64KB entry into two 32KB entries instead.
		*/
		if (count++ >= PRD_ENTRIES) {
		printk(KERN_ERR "%s: DMA table too small\n", drive->name);
		if (xcount == 0x0000) {
		if (count++ >= PRD_ENTRIES)
		goto use_pio_instead;
		}
		*table++ = cpu_to_le32(0x8000);
		*table++ = cpu_to_le32(cur_addr + 0x8000);
		xcount = 0x8000;
		@@ -223,24 +214,20 @@ int ide_build_dmatable (ide_drive_t drive, struct request rq)
		}
		}

		sg = sg_next(sg);
		i--;
		}

		if (count) {
		if (!is_trm290)
		*--table \|= cpu_to_le32(0x80000000);
		return count;
		}

		printk(KERN_ERR "%s: empty DMA table?\n", drive->name);

		use_pio_instead:
		printk(KERN_ERR "%s: %s\n", drive->name,
		count ? "DMA table too small" : "empty DMA table?");

		ide_destroy_dmatable(drive);

		return 0; /* revert to PIO for this request */
		}

		EXPORT_SYMBOL_GPL(ide_build_dmatable);
		#endif

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