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Commit 1540035d authored by Suman Tripathi's avatar Suman Tripathi Committed by Tejun Heo
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ahci_xgene: Implement the xgene_ahci_poll_reg_val to support PMP. 



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: default avatarSuman Tripathi <stripathi@apm.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent b84b25cb

drivers/ata/ahci_xgene.c

+54 −2
Original line number Diff line number Diff line
@@ -104,18 +104,70 @@ static int xgene_ahci_init_memram(struct xgene_ahci_context *ctx) 
	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.

 * @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,