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ahci: Workaround for ThunderX Errata#22536

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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: Tirumalesh Chalamarla <tchalamarla@caviumnetworks.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tirumalesh Chalamarla 2016-02-16 12:08:49 -08:00 committed by Tejun Heo
parent 4ee34ea3a1
commit d243bed32f
1 changed files with 43 additions and 0 deletions
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43
drivers/ata/ahci.c
View file

@ -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);