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Subject[PATCH 2.6.14-rc2 1/2] libata: Marvell spinlock fixes and simplification
Date
This patch should fix up lockups that people were seeing due to
improper spinlock placement. Also, the start/stop DMA routines put
guarded trust in the cached state of DMA.

Thanks,
BR

Signed-off-by: Brett Russ <russb@emc.com>


Index: linux-2.6.14-rc2/drivers/scsi/sata_mv.c
===================================================================
--- linux-2.6.14-rc2.orig/drivers/scsi/sata_mv.c
+++ linux-2.6.14-rc2/drivers/scsi/sata_mv.c
@@ -35,7 +35,7 @@
#include <asm/io.h>

#define DRV_NAME "sata_mv"
-#define DRV_VERSION "0.22"
+#define DRV_VERSION "0.23"

enum {
/* BAR's are enumerated in terms of pci_resource_start() terms */
@@ -406,40 +406,30 @@ static void mv_irq_clear(struct ata_port
{
}

-static void mv_start_dma(void __iomem *base, struct mv_port_priv *pp,
- struct ata_port *ap)
+static void mv_start_dma(void __iomem *base, struct mv_port_priv *pp)
{
- unsigned long flags;
-
- spin_lock_irqsave(&ap->host_set->lock, flags);
-
- writelfl(EDMA_EN, base + EDMA_CMD_OFS);
- pp->pp_flags |= MV_PP_FLAG_EDMA_EN;
-
- spin_unlock_irqrestore(&ap->host_set->lock, flags);
+ if (!(MV_PP_FLAG_EDMA_EN & pp->pp_flags)) {
+ writelfl(EDMA_EN, base + EDMA_CMD_OFS);
+ pp->pp_flags |= MV_PP_FLAG_EDMA_EN;
+ }
+ assert(EDMA_EN & readl(base + EDMA_CMD_OFS));
}

static void mv_stop_dma(struct ata_port *ap)
{
void __iomem *port_mmio = mv_ap_base(ap);
struct mv_port_priv *pp = ap->private_data;
- unsigned long flags;
u32 reg;
int i;

- spin_lock_irqsave(&ap->host_set->lock, flags);
-
- if (!(MV_PP_FLAG_EDMA_DS_ACT & pp->pp_flags) &&
- ((MV_PP_FLAG_EDMA_EN & pp->pp_flags) ||
- (EDMA_EN & readl(port_mmio + EDMA_CMD_OFS)))) {
- /* Disable EDMA if we're not already trying to disable it
- * and it is currently active. The disable bit auto clears.
+ if (MV_PP_FLAG_EDMA_EN & pp->pp_flags) {
+ /* Disable EDMA if active. The disable bit auto clears.
*/
- pp->pp_flags |= MV_PP_FLAG_EDMA_DS_ACT;
writelfl(EDMA_DS, port_mmio + EDMA_CMD_OFS);
pp->pp_flags &= ~MV_PP_FLAG_EDMA_EN;
- }
- spin_unlock_irqrestore(&ap->host_set->lock, flags);
+ } else {
+ assert(!(EDMA_EN & readl(port_mmio + EDMA_CMD_OFS)));
+ }

/* now properly wait for the eDMA to stop */
for (i = 1000; i > 0; i--) {
@@ -450,12 +440,9 @@ static void mv_stop_dma(struct ata_port
udelay(100);
}

- spin_lock_irqsave(&ap->host_set->lock, flags);
- pp->pp_flags &= ~MV_PP_FLAG_EDMA_DS_ACT;
- spin_unlock_irqrestore(&ap->host_set->lock, flags);
-
if (EDMA_EN & reg) {
printk(KERN_ERR "ata%u: Unable to stop eDMA\n", ap->id);
+ /* FIXME: Consider doing a reset here to recover */
}
}

@@ -716,8 +703,11 @@ static void mv_port_stop(struct ata_port
{
struct device *dev = ap->host_set->dev;
struct mv_port_priv *pp = ap->private_data;
+ unsigned long flags;

+ spin_lock_irqsave(&ap->host_set->lock, flags);
mv_stop_dma(ap);
+ spin_unlock_irqrestore(&ap->host_set->lock, flags);

ap->private_data = NULL;
dma_free_coherent(dev, MV_PORT_PRIV_DMA_SZ, pp->crpb, pp->crpb_dma);
@@ -867,11 +857,7 @@ static int mv_qc_issue(struct ata_queued

mv_inc_q_index(&pp->req_producer); /* now incr producer index */

- if (!(MV_PP_FLAG_EDMA_EN & pp->pp_flags)) {
- /* turn on EDMA if not already on */
- mv_start_dma(port_mmio, pp, qc->ap);
- }
- assert(EDMA_EN & readl(port_mmio + EDMA_CMD_OFS));
+ mv_start_dma(port_mmio, pp);

/* and write the request in pointer to kick the EDMA to life */
in_ptr &= EDMA_REQ_Q_BASE_LO_MASK;
@@ -921,8 +907,12 @@ static void mv_err_intr(struct ata_port
serr = scr_read(ap, SCR_ERROR);
scr_write_flush(ap, SCR_ERROR, serr);
}
- DPRINTK("port %u error; EDMA err cause: 0x%08x SERR: 0x%08x\n",
- ap->port_no, edma_err_cause, serr);
+ if (EDMA_ERR_SELF_DIS & edma_err_cause) {
+ struct mv_port_priv *pp = ap->private_data;
+ pp->pp_flags &= ~MV_PP_FLAG_EDMA_EN;
+ }
+ DPRINTK(KERN_ERR "ata%u: port error; EDMA err cause: 0x%08x "
+ "SERR: 0x%08x\n", ap->id, edma_err_cause, serr);

/* Clear EDMA now that SERR cleanup done */
writelfl(0, port_mmio + EDMA_ERR_IRQ_CAUSE_OFS);
@@ -1034,7 +1024,7 @@ static irqreturn_t mv_interrupt(int irq,
printk(KERN_ERR DRV_NAME ": PCI ERROR; PCI IRQ cause=0x%08x\n",
readl(mmio + PCI_IRQ_CAUSE_OFS));

- VPRINTK("All regs @ PCI error\n");
+ DPRINTK("All regs @ PCI error\n");
mv_dump_all_regs(mmio, -1, to_pci_dev(host_set->dev));

writelfl(0, mmio + PCI_IRQ_CAUSE_OFS);
-
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