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| author | Hannes Reinecke <hare@suse.de> | 2014-11-24 15:37:26 +0100 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2014-11-24 16:13:15 +0100 |
| commit | 6df388f2d549d3a2a7ad58b632d2ecd25fc0ff3f (patch) | |
| tree | 7b663c4ebd1da38079723da2989e7f44388a52f2 /drivers/scsi | |
| parent | 3a7e7be2a9a2105742c3c88d466ea2158a03a837 (diff) | |
| download | linux-6df388f2d549d3a2a7ad58b632d2ecd25fc0ff3f.tar.gz linux-6df388f2d549d3a2a7ad58b632d2ecd25fc0ff3f.tar.bz2 linux-6df388f2d549d3a2a7ad58b632d2ecd25fc0ff3f.zip | |
am53c974: BLAST residual handling
The am53c974 has an design issue where a single byte might be
left in the SCSI FIFO after a DMA transfer.
As the handling code is currently untested add a WARN_ON()
statement here.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/scsi')
| -rw-r--r-- | drivers/scsi/am53c974.c | 6 | ||||
| -rw-r--r-- | drivers/scsi/esp_scsi.c | 29 | ||||
| -rw-r--r-- | drivers/scsi/esp_scsi.h | 1 |
3 files changed, 36 insertions, 0 deletions
diff --git a/drivers/scsi/am53c974.c b/drivers/scsi/am53c974.c index a16c9cf0f0a2..a42e8db057a4 100644 --- a/drivers/scsi/am53c974.c +++ b/drivers/scsi/am53c974.c @@ -200,6 +200,12 @@ static void pci_esp_dma_drain(struct esp *esp) } pci_esp_write8(esp, ESP_DMA_CMD_DIR | ESP_DMA_CMD_IDLE, ESP_DMA_CMD); esp_dma_log("DMA blast done (%d tries, %d bytes left)\n", lim, resid); + /* BLAST residual handling is currently untested */ + if (WARN_ON_ONCE(resid == 1)) { + struct esp_cmd_entry *ent = esp->active_cmd; + + ent->flags |= ESP_CMD_FLAG_RESIDUAL; + } } static void pci_esp_dma_invalidate(struct esp *esp) diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c index 25cc6fa0535c..4366011cd400 100644 --- a/drivers/scsi/esp_scsi.c +++ b/drivers/scsi/esp_scsi.c @@ -1334,6 +1334,35 @@ static int esp_data_bytes_sent(struct esp *esp, struct esp_cmd_entry *ent, bytes_sent = esp->data_dma_len; bytes_sent -= ecount; + /* + * The am53c974 has a DMA 'pecularity'. The doc states: + * In some odd byte conditions, one residual byte will + * be left in the SCSI FIFO, and the FIFO Flags will + * never count to '0 '. When this happens, the residual + * byte should be retrieved via PIO following completion + * of the BLAST operation. + */ + if (fifo_cnt == 1 && ent->flags & ESP_CMD_FLAG_RESIDUAL) { + size_t count = 1; + size_t offset = bytes_sent; + u8 bval = esp_read8(ESP_FDATA); + + if (ent->flags & ESP_CMD_FLAG_AUTOSENSE) + ent->sense_ptr[bytes_sent] = bval; + else { + struct esp_cmd_priv *p = ESP_CMD_PRIV(cmd); + u8 *ptr; + + ptr = scsi_kmap_atomic_sg(p->cur_sg, p->u.num_sg, + &offset, &count); + if (likely(ptr)) { + *(ptr + offset) = bval; + scsi_kunmap_atomic_sg(ptr); + } + } + bytes_sent += fifo_cnt; + ent->flags &= ~ESP_CMD_FLAG_RESIDUAL; + } if (!(ent->flags & ESP_CMD_FLAG_WRITE)) bytes_sent -= fifo_cnt; diff --git a/drivers/scsi/esp_scsi.h b/drivers/scsi/esp_scsi.h index 27dcaf84e717..5fa456cc5e8b 100644 --- a/drivers/scsi/esp_scsi.h +++ b/drivers/scsi/esp_scsi.h @@ -269,6 +269,7 @@ struct esp_cmd_entry { #define ESP_CMD_FLAG_WRITE 0x01 /* DMA is a write */ #define ESP_CMD_FLAG_ABORT 0x02 /* being aborted */ #define ESP_CMD_FLAG_AUTOSENSE 0x04 /* Doing automatic REQUEST_SENSE */ +#define ESP_CMD_FLAG_RESIDUAL 0x08 /* AM53c974 BLAST residual */ u8 tag[2]; u8 orig_tag[2]; |