From 351129c7bb979982c2ced90fe5b9e832d35e2b76 Mon Sep 17 00:00:00 2001 From: Nathan Whitehorn Date: Sun, 6 Jun 2010 14:09:48 +0000 Subject: [PATCH] Some revisions of the Serverworks K2 SATA controller have a data corruption bug where if an ATA command is issued before DMA is started, data will become available to the controller before it knows what to do with it. This results in either data corruption or a controller crash. This patch remedies the problem by adopting the workaround employed by Linux and Darwin: starting the DMA engine prior to sending the ATA command. Observer on: Xserve G5 Reviewed by: mav MFC after: 1 week --- sys/dev/ata/ata-all.h | 1 + sys/dev/ata/ata-lowlevel.c | 11 ++++++++++- sys/dev/ata/chipsets/ata-serverworks.c | 10 ++++++++++ 3 files changed, 21 insertions(+), 1 deletion(-) diff --git a/sys/dev/ata/ata-all.h b/sys/dev/ata/ata-all.h index d7b3f4412d6..336f0e3966e 100644 --- a/sys/dev/ata/ata-all.h +++ b/sys/dev/ata/ata-all.h @@ -564,6 +564,7 @@ struct ata_channel { #define ATA_CHECKS_CABLE 0x20 #define ATA_NO_ATAPI_DMA 0x40 #define ATA_SATA 0x80 +#define ATA_DMA_BEFORE_CMD 0x100 int pm_level; /* power management level */ int devices; /* what is present */ diff --git a/sys/dev/ata/ata-lowlevel.c b/sys/dev/ata/ata-lowlevel.c index 566b8f676a5..6c196d60a44 100644 --- a/sys/dev/ata/ata-lowlevel.c +++ b/sys/dev/ata/ata-lowlevel.c @@ -141,6 +141,14 @@ ata_begin_transaction(struct ata_request *request) goto begin_finished; } + /* start DMA engine if necessary */ + if ((ch->flags & ATA_DMA_BEFORE_CMD) && + ch->dma.start && ch->dma.start(request)) { + device_printf(request->parent, "error starting DMA\n"); + request->result = EIO; + goto begin_finished; + } + /* issue command */ if (ch->hw.command(request)) { device_printf(request->parent, "error issuing %s command\n", @@ -150,7 +158,8 @@ ata_begin_transaction(struct ata_request *request) } /* start DMA engine */ - if (ch->dma.start && ch->dma.start(request)) { + if (!(ch->flags & ATA_DMA_BEFORE_CMD) && + ch->dma.start && ch->dma.start(request)) { device_printf(request->parent, "error starting DMA\n"); request->result = EIO; goto begin_finished; diff --git a/sys/dev/ata/chipsets/ata-serverworks.c b/sys/dev/ata/chipsets/ata-serverworks.c index 29718ec5e48..cee56e3681e 100644 --- a/sys/dev/ata/chipsets/ata-serverworks.c +++ b/sys/dev/ata/chipsets/ata-serverworks.c @@ -241,6 +241,16 @@ ata_serverworks_ch_attach(device_t dev) ATA_OUTL(ctlr->r_res2, ch_offset + 0x88, 0); ATA_OUTL(ctlr->r_res2, ch_offset + 0x80, ATA_INL(ctlr->r_res2, ch_offset + 0x80) & ~0x00040000); + + /* + * Some controllers have a bug where they will send the command + * to the drive before seeing a DMA start, and then can begin + * receiving data before the DMA start arrives. The controller + * will then become confused and either corrupt the data or crash. + * Remedy this by starting DMA before sending the drive command. + */ + + ch->flags |= ATA_DMA_BEFORE_CMD; } /* chip does not reliably do 64K DMA transfers */