From cedc9a478d8c6265879dc3839ef3d4849a709184 Mon Sep 17 00:00:00 2001 From: Jeff Garzik Date: Wed, 5 Oct 2005 07:13:30 -0400 Subject: libata: fix ATAPI DMA alignment issues ATAPI needs to be padded to next 4 byte boundary, if misaligned. Original work by me, many fixes from Tejun Heo. --- include/linux/libata.h | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) (limited to 'include/linux/libata.h') diff --git a/include/linux/libata.h b/include/linux/libata.h index ceee1fc42c6..3ab67622ef9 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -154,6 +154,10 @@ enum { ATA_SHIFT_UDMA = 0, ATA_SHIFT_MWDMA = 8, ATA_SHIFT_PIO = 11, + + /* size of buffer to pad xfers ending on unaligned boundaries */ + ATA_DMA_PAD_SZ = 4, + ATA_DMA_PAD_BUF_SZ = ATA_DMA_PAD_SZ * ATA_MAX_QUEUE, }; enum pio_task_states { @@ -237,9 +241,12 @@ struct ata_queued_cmd { unsigned long flags; /* ATA_QCFLAG_xxx */ unsigned int tag; unsigned int n_elem; + unsigned int orig_n_elem; int dma_dir; + unsigned int pad_len; + unsigned int nsect; unsigned int cursect; @@ -250,9 +257,11 @@ struct ata_queued_cmd { unsigned int cursg_ofs; struct scatterlist sgent; + struct scatterlist pad_sgent; void *buf_virt; - struct scatterlist *sg; + /* DO NOT iterate over __sg manually, use ata_for_each_sg() */ + struct scatterlist *__sg; ata_qc_cb_t complete_fn; @@ -295,6 +304,9 @@ struct ata_port { struct ata_prd *prd; /* our SG list */ dma_addr_t prd_dma; /* and its DMA mapping */ + void *pad; /* array of DMA pad buffers */ + dma_addr_t pad_dma; + struct ata_ioports ioaddr; /* ATA cmd/ctl/dma register blocks */ u8 ctl; /* cache of ATA control register */ @@ -458,6 +470,19 @@ extern int pci_test_config_bits(struct pci_dev *pdev, struct pci_bits *bits); #endif /* CONFIG_PCI */ +static inline struct scatterlist * +ata_qc_next_sg(struct scatterlist *sg, struct ata_queued_cmd *qc) +{ + if (sg == &qc->pad_sgent) + return NULL; + if (++sg - qc->__sg < qc->n_elem) + return sg; + return qc->pad_len ? &qc->pad_sgent : NULL; +} + +#define ata_for_each_sg(sg, qc) \ + for (sg = qc->__sg; sg; sg = ata_qc_next_sg(sg, qc)) + static inline unsigned int ata_tag_valid(unsigned int tag) { return (tag < ATA_MAX_QUEUE) ? 1 : 0; -- cgit v1.2.3