[libata] support for > 512 byte sectors (e.g. 4K Native)

This change enables my x86 machine to recognize and talk to a
"Native 4K" SATA device.

When I started working on this, I didn't know Matthew Wilcox had
posted a similar patch 2 years ago:
  http://git.kernel.org/?p=linux/kernel/git/willy/ata.git;a=shortlog;h=refs/heads/ata-large-sectors

Gwendal Grignou pointed me at the the above code and small portions of
this patch include Matthew's work. That's why Mathew is first on the
"Signed-off-by:". I've NOT included his use of a bitmap to determine
512 vs Native for ATA command block size - just used a simple table.
And bugs are almost certainly mine.

Lastly, the patch has been tested with a native 4K 'Engineering
Sample' drive provided by Hitachi GST.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Grant Grundler <grundler@google.com>
Reviewed-by: Gwendal Grignou <gwendal@google.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

2 files changed, 105 insertions, 37 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index c16f5c15173..f1c0118c6d4 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -53,7 +53,6 @@
 #include "libata.h"
 #include "libata-transport.h"
 
-#define SECTOR_SIZE             512
 #define ATA_SCSI_RBUF_SIZE      4096
 
 static DEFINE_SPINLOCK(ata_scsi_rbuf_lock);
@@ -503,7 +502,7 @@ int ata_cmd_ioctl(struct scsi_device *scsidev, void __user *arg)
         memset(scsi_cmd, 0, sizeof(scsi_cmd));
 
         if (args[3]) {
-                argsize = SECTOR_SIZE * args[3];
+                argsize = ATA_SECT_SIZE * args[3];
                 argbuf = kmalloc(argsize, GFP_KERNEL);
                 if (argbuf == NULL) {
                         rc = -ENOMEM;
@@ -1137,8 +1136,9 @@ static int ata_scsi_dev_config(struct scsi_device *sdev,
                 blk_queue_dma_drain(q, atapi_drain_needed, buf, ATAPI_MAX_DRAIN);
         } else {
                 /* ATA devices must be sector aligned */
+                sdev->sector_size = ata_id_logical_sector_size(dev->id);
                 blk_queue_update_dma_alignment(sdev->request_queue,
-                                               ATA_SECT_SIZE - 1);
+                                               sdev->sector_size - 1);
                 sdev->manage_start_stop = 1;
         }
 
@@ -1153,6 +1153,7 @@ static int ata_scsi_dev_config(struct scsi_device *sdev,
                 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
         }
 
+        dev->sdev = sdev;
         return 0;
 }
 
@@ -1683,7 +1684,7 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc)
                 goto nothing_to_do;
 
         qc->flags |= ATA_QCFLAG_IO;
-        qc->nbytes = n_block * ATA_SECT_SIZE;
+        qc->nbytes = n_block * scmd->device->sector_size;
 
         rc = ata_build_rw_tf(&qc->tf, qc->dev, block, n_block, tf_flags,
                              qc->tag);
@@ -2110,7 +2111,7 @@ static unsigned int ata_scsiop_inq_89(struct ata_scsi_args *args, u8 *rbuf)
 
 static unsigned int ata_scsiop_inq_b0(struct ata_scsi_args *args, u8 *rbuf)
 {
-        u32 min_io_sectors;
+        u16 min_io_sectors;
 
         rbuf[1] = 0xb0;
         rbuf[3] = 0x3c;         /* required VPD size with unmap support */
@@ -2122,10 +2123,7 @@ static unsigned int ata_scsiop_inq_b0(struct ata_scsi_args *args, u8 *rbuf)
          * logical than physical sector size we need to figure out what the
          * latter is.
          */
-        if (ata_id_has_large_logical_sectors(args->id))
-                min_io_sectors = ata_id_logical_per_physical_sectors(args->id);
-        else
-                min_io_sectors = 1;
+        min_io_sectors = 1 << ata_id_log2_per_physical_sector(args->id);
         put_unaligned_be16(min_io_sectors, &rbuf[6]);
 
         /*
@@ -2384,21 +2382,13 @@ static unsigned int ata_scsiop_read_cap(struct ata_scsi_args *args, u8 *rbuf)
 {
         struct ata_device *dev = args->dev;
         u64 last_lba = dev->n_sectors - 1; /* LBA of the last block */
-        u8 log_per_phys = 0;
-        u16 lowest_aligned = 0;
-        u16 word_106 = dev->id[106];
-        u16 word_209 = dev->id[209];
-
-        if ((word_106 & 0xc000) == 0x4000) {
-                /* Number and offset of logical sectors per physical sector */
-                if (word_106 & (1 << 13))
-                        log_per_phys = word_106 & 0xf;
-                if ((word_209 & 0xc000) == 0x4000) {
-                        u16 first = dev->id[209] & 0x3fff;
-                        if (first > 0)
-                                lowest_aligned = (1 << log_per_phys) - first;
-                }
-        }
+        u32 sector_size; /* physical sector size in bytes */
+        u8 log2_per_phys;
+        u16 lowest_aligned;
+
+        sector_size = ata_id_logical_sector_size(dev->id);
+        log2_per_phys = ata_id_log2_per_physical_sector(dev->id);
+        lowest_aligned = ata_id_logical_sector_offset(dev->id, log2_per_phys);
 
         VPRINTK("ENTER\n");
 
@@ -2413,8 +2403,10 @@ static unsigned int ata_scsiop_read_cap(struct ata_scsi_args *args, u8 *rbuf)
                 rbuf[3] = last_lba;
 
                 /* sector size */
-                rbuf[6] = ATA_SECT_SIZE >> 8;
-                rbuf[7] = ATA_SECT_SIZE & 0xff;
+                rbuf[4] = sector_size >> (8 * 3);
+                rbuf[5] = sector_size >> (8 * 2);
+                rbuf[6] = sector_size >> (8 * 1);
+                rbuf[7] = sector_size;
         } else {
                 /* sector count, 64-bit */
                 rbuf[0] = last_lba >> (8 * 7);
@@ -2427,11 +2419,13 @@ static unsigned int ata_scsiop_read_cap(struct ata_scsi_args *args, u8 *rbuf)
                 rbuf[7] = last_lba;
 
                 /* sector size */
-                rbuf[10] = ATA_SECT_SIZE >> 8;
-                rbuf[11] = ATA_SECT_SIZE & 0xff;
+                rbuf[ 8] = sector_size >> (8 * 3);
+                rbuf[ 9] = sector_size >> (8 * 2);
+                rbuf[10] = sector_size >> (8 * 1);
+                rbuf[11] = sector_size;
 
                 rbuf[12] = 0;
-                rbuf[13] = log_per_phys;
+                rbuf[13] = log2_per_phys;
                 rbuf[14] = (lowest_aligned >> 8) & 0x3f;
                 rbuf[15] = lowest_aligned;
 
@@ -2875,9 +2869,8 @@ static unsigned int ata_scsi_pass_thru(struct ata_queued_cmd *qc)
         tf->device = dev->devno ?
                 tf->device | ATA_DEV1 : tf->device & ~ATA_DEV1;
 
-        /* READ/WRITE LONG use a non-standard sect_size */
-        qc->sect_size = ATA_SECT_SIZE;
         switch (tf->command) {
+        /* READ/WRITE LONG use a non-standard sect_size */
         case ATA_CMD_READ_LONG:
         case ATA_CMD_READ_LONG_ONCE:
         case ATA_CMD_WRITE_LONG:
@@ -2885,6 +2878,45 @@ static unsigned int ata_scsi_pass_thru(struct ata_queued_cmd *qc)
                 if (tf->protocol != ATA_PROT_PIO || tf->nsect != 1)
                         goto invalid_fld;
                 qc->sect_size = scsi_bufflen(scmd);
+                break;
+
+        /* commands using reported Logical Block size (e.g. 512 or 4K) */
+        case ATA_CMD_CFA_WRITE_NE:
+        case ATA_CMD_CFA_TRANS_SECT:
+        case ATA_CMD_CFA_WRITE_MULT_NE:
+        /* XXX: case ATA_CMD_CFA_WRITE_SECTORS_WITHOUT_ERASE: */
+        case ATA_CMD_READ:
+        case ATA_CMD_READ_EXT:
+        case ATA_CMD_READ_QUEUED:
+        /* XXX: case ATA_CMD_READ_QUEUED_EXT: */
+        case ATA_CMD_FPDMA_READ:
+        case ATA_CMD_READ_MULTI:
+        case ATA_CMD_READ_MULTI_EXT:
+        case ATA_CMD_PIO_READ:
+        case ATA_CMD_PIO_READ_EXT:
+        case ATA_CMD_READ_STREAM_DMA_EXT:
+        case ATA_CMD_READ_STREAM_EXT:
+        case ATA_CMD_VERIFY:
+        case ATA_CMD_VERIFY_EXT:
+        case ATA_CMD_WRITE:
+        case ATA_CMD_WRITE_EXT:
+        case ATA_CMD_WRITE_FUA_EXT:
+        case ATA_CMD_WRITE_QUEUED:
+        case ATA_CMD_WRITE_QUEUED_FUA_EXT:
+        case ATA_CMD_FPDMA_WRITE:
+        case ATA_CMD_WRITE_MULTI:
+        case ATA_CMD_WRITE_MULTI_EXT:
+        case ATA_CMD_WRITE_MULTI_FUA_EXT:
+        case ATA_CMD_PIO_WRITE:
+        case ATA_CMD_PIO_WRITE_EXT:
+        case ATA_CMD_WRITE_STREAM_DMA_EXT:
+        case ATA_CMD_WRITE_STREAM_EXT:
+                qc->sect_size = scmd->device->sector_size;
+                break;
+
+        /* Everything else uses 512 byte "sectors" */
+        default:
+                qc->sect_size = ATA_SECT_SIZE;
         }
 
         /*
@@ -3380,6 +3412,8 @@ void ata_scsi_scan_host(struct ata_port *ap, int sync)
                         if (!IS_ERR(sdev)) {
                                 dev->sdev = sdev;
                                 scsi_device_put(sdev);
+                        } else {
+                                dev->sdev = NULL;
                         }
                 }
         }
diff --git a/include/linux/ata.h b/include/linux/ata.h
index fe6e681a9d7..0c4929fa34d 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -89,6 +89,7 @@ enum {
         ATA_ID_SPG              = 98,
         ATA_ID_LBA_CAPACITY_2   = 100,
         ATA_ID_SECTOR_SIZE      = 106,
+        ATA_ID_LOGICAL_SECTOR_SIZE      = 117,  /* and 118 */
         ATA_ID_LAST_LUN         = 126,
         ATA_ID_DLF              = 128,
         ATA_ID_CSFO             = 129,
@@ -640,16 +641,49 @@ static inline int ata_id_flush_ext_enabled(const u16 *id)
         return (id[ATA_ID_CFS_ENABLE_2] & 0x2400) == 0x2400;
 }
 
-static inline int ata_id_has_large_logical_sectors(const u16 *id)
+static inline u32 ata_id_logical_sector_size(const u16 *id)
 {
-        if ((id[ATA_ID_SECTOR_SIZE] & 0xc000) != 0x4000)
-                return 0;
-        return id[ATA_ID_SECTOR_SIZE] & (1 << 13);
+        /* T13/1699-D Revision 6a, Sep 6, 2008. Page 128.
+         * IDENTIFY DEVICE data, word 117-118.
+         * 0xd000 ignores bit 13 (logical:physical > 1)
+         */
+        if ((id[ATA_ID_SECTOR_SIZE] & 0xd000) == 0x5000)
+                return (((id[ATA_ID_LOGICAL_SECTOR_SIZE+1] << 16)
+                         + id[ATA_ID_LOGICAL_SECTOR_SIZE]) * sizeof(u16)) ;
+        return ATA_SECT_SIZE;
+}
+
+static inline u8 ata_id_log2_per_physical_sector(const u16 *id)
+{
+        /* T13/1699-D Revision 6a, Sep 6, 2008. Page 128.
+         * IDENTIFY DEVICE data, word 106.
+         * 0xe000 ignores bit 12 (logical sector > 512 bytes)
+         */
+        if ((id[ATA_ID_SECTOR_SIZE] & 0xe000) == 0x6000)
+                return (id[ATA_ID_SECTOR_SIZE] & 0xf);
+        return 0;
 }
 
-static inline u16 ata_id_logical_per_physical_sectors(const u16 *id)
+/* Offset of logical sectors relative to physical sectors.
+ *
+ * If device has more than one logical sector per physical sector
+ * (aka 512 byte emulation), vendors might offset the "sector 0" address
+ * so sector 63 is "naturally aligned" - e.g. FAT partition table.
+ * This avoids Read/Mod/Write penalties when using FAT partition table
+ * and updating "well aligned" (FS perspective) physical sectors on every
+ * transaction.
+ */
+static inline u16 ata_id_logical_sector_offset(const u16 *id,
+         u8 log2_per_phys)
 {
-        return 1 << (id[ATA_ID_SECTOR_SIZE] & 0xf);
+        u16 word_209 = id[209];
+
+        if ((log2_per_phys > 1) && (word_209 & 0xc000) == 0x4000) {
+                u16 first = word_209 & 0x3fff;
+                if (first > 0)
+                        return (1 << log2_per_phys) - first;
+        }
+        return 0;
 }
 
 static inline int ata_id_has_lba48(const u16 *id)