[PATCH] libata: Marvell spinlock fixes and simplification

This 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.

Signed-off-by: Brett Russ <russb@emc.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

1 files changed, 24 insertions, 34 deletions

diff --git a/drivers/scsi/sata_mv.c b/drivers/scsi/sata_mv.c
index ecda7df21142..c3084f8b3ee7 100644
--- a/drivers/scsi/sata_mv.c
+++ b/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 *ap)
 {
 }
 
-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 *ap)
                 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 *ap)
 {
         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_cmd *qc)
 
         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 *ap)
                 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, void *dev_instance,
                 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);