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Subject[112/156] icside: bring back ->maskproc method
2.6.33-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

[ Upstream commit f75d4a238770d83d3a0475ce7f34e3fa37de161e ]

Bring back ->maskproc method since it is still needed for proper operation,
as noticed by Russell King:

> This change is bogus.
>
> writeb(0, base + ICS_ARCIN_V6_INTROFFSET_1);
> readb(base + ICS_ARCIN_V6_INTROFFSET_2);
>
> writeb(0, base + ICS_ARCIN_V6_INTROFFSET_2);
> readb(base + ICS_ARCIN_V6_INTROFFSET_1);
>
> This sequence of code does:
>
> 1. enable interrupt 1
> 2. disable interrupt 2
> 3. enable interrupt 2
> 4. disable interrupt 1
>
> which results in the interrupt for the second channel being enabled -
> leaving channel 1 blocked.
>
> Firstly, icside shares its two IDE channels with one DMA engine - so it's
> a simplex interface. IDE supports those (or did when the code was written)
> serializing requests between the two interfaces. libata does not.
>
> Secondly, the interrupt lines on icside float when there's no drive connected
> or when the drive has its NIEN bit set, which means that you get spurious
> screaming interrupts which can kill off all expansion card interrupts on
> the machine unless you disable the channel interrupt on the card.
>
> Since libata can not serialize the operation of the two channels like IDE
> can, the libata version of the icside driver does not contain the interrupt
> stearing logic. Instead, it looks at the status after reset, and if
> nothing was found on that channel, it masks the interrupt from that
> channel.

This patch reverts changes done in commit dff8817 (I became confused due to
non-standard & undocumented ->maskproc method, anyway sorry about that).

Noticed-by: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/ide/icside.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 60 insertions(+), 4 deletions(-)

--- a/drivers/ide/icside.c
+++ b/drivers/ide/icside.c
@@ -65,6 +65,8 @@ static struct cardinfo icside_cardinfo_v
};

struct icside_state {
+ unsigned int channel;
+ unsigned int enabled;
void __iomem *irq_port;
void __iomem *ioc_base;
unsigned int sel;
@@ -114,11 +116,18 @@ static void icside_irqenable_arcin_v6 (s
struct icside_state *state = ec->irq_data;
void __iomem *base = state->irq_port;

- writeb(0, base + ICS_ARCIN_V6_INTROFFSET_1);
- readb(base + ICS_ARCIN_V6_INTROFFSET_2);
+ state->enabled = 1;

- writeb(0, base + ICS_ARCIN_V6_INTROFFSET_2);
- readb(base + ICS_ARCIN_V6_INTROFFSET_1);
+ switch (state->channel) {
+ case 0:
+ writeb(0, base + ICS_ARCIN_V6_INTROFFSET_1);
+ readb(base + ICS_ARCIN_V6_INTROFFSET_2);
+ break;
+ case 1:
+ writeb(0, base + ICS_ARCIN_V6_INTROFFSET_2);
+ readb(base + ICS_ARCIN_V6_INTROFFSET_1);
+ break;
+ }
}

/* Prototype: icside_irqdisable_arcin_v6 (struct expansion_card *ec, int irqnr)
@@ -128,6 +137,8 @@ static void icside_irqdisable_arcin_v6 (
{
struct icside_state *state = ec->irq_data;

+ state->enabled = 0;
+
readb(state->irq_port + ICS_ARCIN_V6_INTROFFSET_1);
readb(state->irq_port + ICS_ARCIN_V6_INTROFFSET_2);
}
@@ -149,6 +160,44 @@ static const expansioncard_ops_t icside_
.irqpending = icside_irqpending_arcin_v6,
};

+/*
+ * Handle routing of interrupts. This is called before
+ * we write the command to the drive.
+ */
+static void icside_maskproc(ide_drive_t *drive, int mask)
+{
+ ide_hwif_t *hwif = drive->hwif;
+ struct expansion_card *ec = ECARD_DEV(hwif->dev);
+ struct icside_state *state = ecard_get_drvdata(ec);
+ unsigned long flags;
+
+ local_irq_save(flags);
+
+ state->channel = hwif->channel;
+
+ if (state->enabled && !mask) {
+ switch (hwif->channel) {
+ case 0:
+ writeb(0, state->irq_port + ICS_ARCIN_V6_INTROFFSET_1);
+ readb(state->irq_port + ICS_ARCIN_V6_INTROFFSET_2);
+ break;
+ case 1:
+ writeb(0, state->irq_port + ICS_ARCIN_V6_INTROFFSET_2);
+ readb(state->irq_port + ICS_ARCIN_V6_INTROFFSET_1);
+ break;
+ }
+ } else {
+ readb(state->irq_port + ICS_ARCIN_V6_INTROFFSET_2);
+ readb(state->irq_port + ICS_ARCIN_V6_INTROFFSET_1);
+ }
+
+ local_irq_restore(flags);
+}
+
+static const struct ide_port_ops icside_v6_no_dma_port_ops = {
+ .maskproc = icside_maskproc,
+};
+
#ifdef CONFIG_BLK_DEV_IDEDMA_ICS
/*
* SG-DMA support.
@@ -228,6 +277,7 @@ static void icside_set_dma_mode(ide_driv

static const struct ide_port_ops icside_v6_port_ops = {
.set_dma_mode = icside_set_dma_mode,
+ .maskproc = icside_maskproc,
};

static void icside_dma_host_set(ide_drive_t *drive, int on)
@@ -272,6 +322,11 @@ static int icside_dma_setup(ide_drive_t
BUG_ON(dma_channel_active(ec->dma));

/*
+ * Ensure that we have the right interrupt routed.
+ */
+ icside_maskproc(drive, 0);
+
+ /*
* Route the DMA signals to the correct interface.
*/
writeb(state->sel | hwif->channel, state->ioc_base);
@@ -399,6 +454,7 @@ err_free:

static const struct ide_port_info icside_v6_port_info __initdata = {
.init_dma = icside_dma_off_init,
+ .port_ops = &icside_v6_no_dma_port_ops,
.dma_ops = &icside_v6_dma_ops,
.host_flags = IDE_HFLAG_SERIALIZE | IDE_HFLAG_MMIO,
.mwdma_mask = ATA_MWDMA2,



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