From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Milburn Subject: [PATCH] sata_svw: check DMA start bit before reset Date: Mon, 29 Oct 2012 18:00:22 -0500 Message-ID: <1351551622-1193-1-git-send-email-dmilburn@redhat.com> Return-path: Received: from mx1.redhat.com ([209.132.183.28]:14970 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754754Ab2J2WyZ (ORCPT ); Mon, 29 Oct 2012 18:54:25 -0400 Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: jgarzik@pobox.com Cc: linux-ide@vger.kernel.org, benh@kernel.crashing.org, caiqian@redhat.com If kdump is triggered with pending IO, controller may not respond causing kdump to fail. http://marc.info/?l=linux-ide&m=133032255424658&w=2 During error recovery ata_do_dev_read_id never completes due hang in mmio_insw. ata_do_dev_read_id ata_sff_data_xfer ioread16_rep mmio_insw if DMA start bit is cleared before reset, PIO command is successful and kdump succeeds. Signed-off-by: David Milburn --- drivers/ata/sata_svw.c | 35 +++++++++++++++++++++++++++++++++++ 1 files changed, 35 insertions(+), 0 deletions(-) diff --git a/drivers/ata/sata_svw.c b/drivers/ata/sata_svw.c index 44a4256..08608de 100644 --- a/drivers/ata/sata_svw.c +++ b/drivers/ata/sata_svw.c @@ -142,6 +142,39 @@ static int k2_sata_scr_write(struct ata_link *link, return 0; } +static int k2_sata_softreset(struct ata_link *link, + unsigned int *class, unsigned long deadline) +{ + u8 dmactl; + void __iomem *mmio = link->ap->ioaddr.bmdma_addr; + + dmactl = readb(mmio + ATA_DMA_CMD); + + /* Clear the start bit */ + if (dmactl & ATA_DMA_START) { + dmactl &= ~ATA_DMA_START; + writeb(dmactl, mmio + ATA_DMA_CMD); + } + + return ata_sff_softreset(link, class, deadline); +} + +static int k2_sata_hardreset(struct ata_link *link, + unsigned int *class, unsigned long deadline) +{ + u8 dmactl; + void __iomem *mmio = link->ap->ioaddr.bmdma_addr; + + dmactl = readb(mmio + ATA_DMA_CMD); + + /* Clear the start bit */ + if (dmactl & ATA_DMA_START) { + dmactl &= ~ATA_DMA_START; + writeb(dmactl, mmio + ATA_DMA_CMD); + } + + return sata_sff_hardreset(link, class, deadline); +} static void k2_sata_tf_load(struct ata_port *ap, const struct ata_taskfile *tf) { @@ -346,6 +379,8 @@ static struct scsi_host_template k2_sata_sht = { static struct ata_port_operations k2_sata_ops = { .inherits = &ata_bmdma_port_ops, + .softreset = k2_sata_softreset, + .hardreset = k2_sata_hardreset, .sff_tf_load = k2_sata_tf_load, .sff_tf_read = k2_sata_tf_read, .sff_check_status = k2_stat_check_status,