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Commit d243bed3 authored by Tirumalesh Chalamarla's avatar Tirumalesh Chalamarla Committed by Tejun Heo
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ahci: Workaround for ThunderX Errata#22536 



Due to Errata in ThunderX, HOST_IRQ_STAT should be
cleared before leaving the interrupt handler.
The patch attempts to satisfy the need.

Changes from V2:
	- removed newfile
	- code is now under CONFIG_ARM64

Changes from V1:
	- Rebased on top of libata/for-4.6
        - Moved ThunderX intr handler to new file

tj: Minor adjustments to comments.

Signed-off-by: default avatarTirumalesh Chalamarla <tchalamarla@caviumnetworks.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 4ee34ea3

drivers/ata/ahci.c

+43 −0
Original line number Diff line number Diff line
@@ -1331,6 +1331,44 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host) 
{}

#endif



#ifdef CONFIG_ARM64

/*

 * Due to ERRATA#22536, ThunderX needs to handle HOST_IRQ_STAT differently.

 * Workaround is to make sure all pending IRQs are served before leaving

 * handler.

 */

static irqreturn_t ahci_thunderx_irq_handler(int irq, void *dev_instance)

{

	struct ata_host *host = dev_instance;

	struct ahci_host_priv *hpriv;

	unsigned int rc = 0;

	void __iomem *mmio;

	u32 irq_stat, irq_masked;

	unsigned int handled = 1;



	VPRINTK("ENTER\n");

	hpriv = host->private_data;

	mmio = hpriv->mmio;

	irq_stat = readl(mmio + HOST_IRQ_STAT);

	if (!irq_stat)

		return IRQ_NONE;



	do {

		irq_masked = irq_stat & hpriv->port_map;

		spin_lock(&host->lock);

		rc = ahci_handle_port_intr(host, irq_masked);

		if (!rc)

			handled = 0;

		writel(irq_stat, mmio + HOST_IRQ_STAT);

		irq_stat = readl(mmio + HOST_IRQ_STAT);

		spin_unlock(&host->lock);

	} while (irq_stat);

	VPRINTK("EXIT\n");



	return IRQ_RETVAL(handled);

}

#endif



/*

 * ahci_init_msix() - optionally enable per-port MSI-X otherwise defer

 * to single msi.
@@ -1566,6 +1604,11 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) 
	if (ahci_broken_devslp(pdev))

		hpriv->flags |= AHCI_HFLAG_NO_DEVSLP;



#ifdef CONFIG_ARM64

	if (pdev->vendor == 0x177d && pdev->device == 0xa01c)

		hpriv->irq_handler = ahci_thunderx_irq_handler;

#endif



	/* save initial config */

	ahci_pci_save_initial_config(pdev, hpriv);