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ahci_xgene: Implement the xgene_ahci_poll_reg_val to support PMP.

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This patch implements the function xgene_ahci_poll_reg_val
to poll PxCI for multiple IDENTIFY DEVICE commands to finish before
restarting the DMA engine.

Signed-off-by: Suman Tripathi <stripathi@apm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Suman Tripathi 2015-01-06 15:32:15 +05:30 committed by Tejun Heo
parent b84b25cb09
commit 1540035da7
1 changed files with 54 additions and 2 deletions
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56
drivers/ata/ahci_xgene.c
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@ -104,18 +104,70 @@ static int xgene_ahci_init_memram(struct xgene_ahci_context *ctx)
return 0; return 0;
} }
/**
* xgene_ahci_poll_reg_val- Poll a register on a specific value.
* @ap : ATA port of interest.
* @reg : Register of interest.
* @val : Value to be attained.
* @interval : waiting interval for polling.
* @timeout : timeout for achieving the value.
*/
static int xgene_ahci_poll_reg_val(struct ata_port *ap,
void __iomem *reg, unsigned
int val, unsigned long interval,
unsigned long timeout)
{
unsigned long deadline;
unsigned int tmp;
tmp = ioread32(reg);
deadline = ata_deadline(jiffies, timeout);
while (tmp != val && time_before(jiffies, deadline)) {
ata_msleep(ap, interval);
tmp = ioread32(reg);
}
return tmp;
}
/** /**
* xgene_ahci_restart_engine - Restart the dma engine. * xgene_ahci_restart_engine - Restart the dma engine.
* @ap : ATA port of interest * @ap : ATA port of interest
* *
* Restarts the dma engine inside the controller. * Waits for completion of multiple commands and restarts
* the DMA engine inside the controller.
*/ */
static int xgene_ahci_restart_engine(struct ata_port *ap) static int xgene_ahci_restart_engine(struct ata_port *ap)
{ {
struct ahci_host_priv *hpriv = ap->host->private_data; struct ahci_host_priv *hpriv = ap->host->private_data;
struct ahci_port_priv *pp = ap->private_data;
void __iomem *port_mmio = ahci_port_base(ap);
u32 fbs;
/*
* In case of PMP multiple IDENTIFY DEVICE commands can be
* issued inside PxCI. So need to poll PxCI for the
* completion of outstanding IDENTIFY DEVICE commands before
* we restart the DMA engine.
*/
if (xgene_ahci_poll_reg_val(ap, port_mmio +
PORT_CMD_ISSUE, 0x0, 1, 100))
return -EBUSY;
ahci_stop_engine(ap); ahci_stop_engine(ap);
ahci_start_fis_rx(ap); ahci_start_fis_rx(ap);
/*
* Enable the PxFBS.FBS_EN bit as it
* gets cleared due to stopping the engine.
*/
if (pp->fbs_supported) {
fbs = readl(port_mmio + PORT_FBS);
writel(fbs | PORT_FBS_EN, port_mmio + PORT_FBS);
fbs = readl(port_mmio + PORT_FBS);
}
hpriv->start_engine(ap); hpriv->start_engine(ap);
return 0; return 0;
@ -374,7 +426,7 @@ static struct ata_port_operations xgene_ahci_ops = {
}; };
static const struct ata_port_info xgene_ahci_port_info = { static const struct ata_port_info xgene_ahci_port_info = {
.flags = AHCI_FLAG_COMMON, .flags = AHCI_FLAG_COMMON | ATA_FLAG_PMP,
.pio_mask = ATA_PIO4, .pio_mask = ATA_PIO4,
.udma_mask = ATA_UDMA6, .udma_mask = ATA_UDMA6,
.port_ops = &xgene_ahci_ops, .port_ops = &xgene_ahci_ops,