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 <[email protected]> --- drivers/ata/ahci_xgene.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 54 insertions(+), 2 deletions(-) diff --git a/drivers/ata/ahci_xgene.c b/drivers/ata/ahci_xgene.c index cbcd208..afa9c03 100644 --- a/drivers/ata/ahci_xgene.c +++ b/drivers/ata/ahci_xgene.c @@ -105,17 +105,69 @@ static int xgene_ahci_init_memram(struct xgene_ahci_context *ctx) } /** + * 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. * @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) { 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_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); return 0; @@ -374,7 +426,7 @@ static struct ata_port_operations xgene_ahci_ops = { }; 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, .udma_mask = ATA_UDMA6, .port_ops = &xgene_ahci_ops, -- 1.8.2.1 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
