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Subject[PATCH 2.6.22-rc5 2/2] sata_promise: SATA hotplug support
This patch enables hotplugging of SATA devices in the
sata_promise driver. It's been tested successfully on
both first- and second-generation Promise SATA chips:
SATA150 TX2plus, SATAII150 TX2plus, SATA300 TX2plus,
and SATA300 TX4.

The only quirk I've seen is that hotplugging (insertion)
on the first-generation SATA150 TX2plus requires a lengthier
EH sequence than on the second-generation chips.
On the second-generation chips a simple soft reset seems
to suffice, but on the first-generation chip there's a
"port is slow to respond" after the initial soft reset,
after which libata issues a hard reset, and then the
device is recognised.

The hotplug checks are high up in the interrupt handling
path, not deep down in error_intr as in ahci/sata_sil24.
That's because the chip doesn't signal hotplug status changes
in the per-port status register: instead a global register
contains hotplug control and status flags for all ports.
I considered following the ahci/sata_sil24 structure, but
that would have required non-trivial changes to the interrupt
handling path, so I chose to keep the hotplug changes simple
and unobtrusive.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
--
This patch depends on patch 1/2: sata_promise: cleanups.

Changes since the preliminary version:
- cleanups
- added testing on the first-generation SATA150 TX2plus

drivers/ata/sata_promise.c | 40 +++++++++++++++++++++++++++++++++++-----
1 files changed, 35 insertions(+), 5 deletions(-)
--- linux-2.6.22-rc5/drivers/ata/sata_promise.c.~1~ 2007-06-19 20:40:28.000000000 +0200
+++ linux-2.6.22-rc5/drivers/ata/sata_promise.c 2007-06-19 20:41:36.000000000 +0200
@@ -45,7 +45,7 @@
#include "sata_promise.h"

#define DRV_NAME "sata_promise"
-#define DRV_VERSION "2.08"
+#define DRV_VERSION "2.09"

enum {
PDC_MAX_PORTS = 4,
@@ -716,6 +716,9 @@ static irqreturn_t pdc_interrupt (int ir
unsigned int i, tmp;
unsigned int handled = 0;
void __iomem *mmio_base;
+ unsigned int hotplug_offset, ata_no;
+ u32 hotplug_status;
+ int is_sataii_tx4;

VPRINTK("ENTER\n");

@@ -726,10 +729,20 @@ static irqreturn_t pdc_interrupt (int ir

mmio_base = host->iomap[PDC_MMIO_BAR];

+ /* read and clear hotplug flags for all ports */
+ if (host->ports[0]->flags & PDC_FLAG_GEN_II)
+ hotplug_offset = PDC2_SATA_PLUG_CSR;
+ else
+ hotplug_offset = PDC_SATA_PLUG_CSR;
+ hotplug_status = readl(mmio_base + hotplug_offset);
+ if (hotplug_status & 0xff)
+ writel(hotplug_status | 0xff, mmio_base + hotplug_offset);
+ hotplug_status &= 0xff; /* clear uninteresting bits */
+
/* reading should also clear interrupts */
mask = readl(mmio_base + PDC_INT_SEQMASK);

- if (mask == 0xffffffff) {
+ if (mask == 0xffffffff && hotplug_status == 0) {
VPRINTK("QUICK EXIT 2\n");
return IRQ_NONE;
}
@@ -737,16 +750,33 @@ static irqreturn_t pdc_interrupt (int ir
spin_lock(&host->lock);

mask &= 0xffff; /* only 16 tags possible */
- if (!mask) {
+ if (mask == 0 && hotplug_status == 0) {
VPRINTK("QUICK EXIT 3\n");
goto done_irq;
}

writel(mask, mmio_base + PDC_INT_SEQMASK);

+ is_sataii_tx4 = pdc_is_sataii_tx4(host->ports[0]->flags);
+
for (i = 0; i < host->n_ports; i++) {
VPRINTK("port %u\n", i);
ap = host->ports[i];
+
+ /* check for a plug or unplug event */
+ ata_no = pdc_port_no_to_ata_no(i, is_sataii_tx4);
+ tmp = hotplug_status & (0x11 << ata_no);
+ if (tmp && ap &&
+ !(ap->flags & ATA_FLAG_DISABLED)) {
+ struct ata_eh_info *ehi = &ap->eh_info;
+ ata_ehi_clear_desc(ehi);
+ ata_ehi_hotplugged(ehi);
+ ata_ehi_push_desc(ehi, "hotplug_status %#x", tmp);
+ ata_port_freeze(ap);
+ continue;
+ }
+
+ /* check for a packet interrupt */
tmp = mask & (1 << (i + 1));
if (tmp && ap &&
!(ap->flags & ATA_FLAG_DISABLED)) {
@@ -902,9 +932,9 @@ static void pdc_host_init(struct ata_hos
tmp = readl(mmio + hotplug_offset);
writel(tmp | 0xff, mmio + hotplug_offset);

- /* mask plug/unplug ints */
+ /* unmask plug/unplug ints */
tmp = readl(mmio + hotplug_offset);
- writel(tmp | 0xff0000, mmio + hotplug_offset);
+ writel(tmp & ~0xff0000, mmio + hotplug_offset);

/* don't initialise TBG or SLEW on 2nd generation chips */
if (is_gen2)
-
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