2017-07-20 19:32:01

by Nate Watterson

Subject: [PATCH] ata: ahci_platform: Add shutdown handler

The newly introduced ahci_platform_shutdown() method is called during
system shutdown to disable host controller DMA and interrupts in order
to avoid potentially corrupting or otherwise interfering with a new
kernel being started with kexec.

Signed-off-by: Nate Watterson <[email protected]>
---
drivers/ata/ahci_platform.c | 1 +
drivers/ata/libahci_platform.c | 34 ++++++++++++++++++++++++++++++++++
include/linux/ahci_platform.h | 2 ++
3 files changed, 37 insertions(+)

diff --git a/drivers/ata/ahci_platform.c b/drivers/ata/ahci_platform.c
index 62a04c8..99f9a89 100644
--- a/drivers/ata/ahci_platform.c
+++ b/drivers/ata/ahci_platform.c
@@ -93,6 +93,7 @@ static SIMPLE_DEV_PM_OPS(ahci_pm_ops, ahci_platform_suspend,
static struct platform_driver ahci_driver = {
.probe = ahci_probe,
.remove = ata_platform_remove_one,
+ .shutdown = ahci_platform_shutdown,
.driver = {
.name = DRV_NAME,
.of_match_table = ahci_of_match,
diff --git a/drivers/ata/libahci_platform.c b/drivers/ata/libahci_platform.c
index cd2eab6..a270a11 100644
--- a/drivers/ata/libahci_platform.c
+++ b/drivers/ata/libahci_platform.c
@@ -602,6 +602,40 @@ static void ahci_host_stop(struct ata_host *host)
ahci_platform_disable_resources(hpriv);
}

+/**
+ * ahci_platform_shutdown - Disable interrupts and stop DMA for host ports
+ * @dev: platform device pointer for the host
+ *
+ * This function is called during system shutdown and performs the minimal
+ * deconfiguration required to ensure that an ahci_platform host cannot
+ * corrupt or otherwise interfere with a new kernel being started with kexec.
+ */
+void ahci_platform_shutdown(struct platform_device *pdev)
+{
+ struct ata_host *host = platform_get_drvdata(pdev);
+ struct ahci_host_priv *hpriv = host->private_data;
+ void __iomem *mmio = hpriv->mmio;
+ int i;
+
+ for (i = 0; i < host->n_ports; i++) {
+ struct ata_port *ap = host->ports[i];
+
+ /* Disable port interrupts */
+ if (ap->ops->freeze)
+ ap->ops->freeze(ap);
+
+ /* Stop the port DMA engines */
+ if (ap->ops->port_stop)
+ ap->ops->port_stop(ap);
+ }
+
+ /* Disable and clear host interrupts */
+ writel(readl(mmio + HOST_CTL) & ~HOST_IRQ_EN, mmio + HOST_CTL);
+ readl(mmio + HOST_CTL); /* flush */
+ writel(GENMASK(host->n_ports, 0), mmio + HOST_IRQ_STAT);
+}
+EXPORT_SYMBOL_GPL(ahci_platform_shutdown);
+
#ifdef CONFIG_PM_SLEEP
/**
* ahci_platform_suspend_host - Suspend an ahci-platform host
diff --git a/include/linux/ahci_platform.h b/include/linux/ahci_platform.h
index a270f25e..1b0a17b 100644
--- a/include/linux/ahci_platform.h
+++ b/include/linux/ahci_platform.h
@@ -36,6 +36,8 @@ int ahci_platform_init_host(struct platform_device *pdev,
const struct ata_port_info *pi_template,
struct scsi_host_template *sht);

+void ahci_platform_shutdown(struct platform_device *pdev);
+
int ahci_platform_suspend_host(struct device *dev);
int ahci_platform_resume_host(struct device *dev);
int ahci_platform_suspend(struct device *dev);
--
Qualcomm Datacenter Technologies, Inc. on behalf of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux
Foundation Collaborative Project.

2017-08-04 20:35:30

by Tejun Heo

Subject: Re: [PATCH] ata: ahci_platform: Add shutdown handler

On Thu, Jul 20, 2017 at 03:26:24PM -0400, Nate Watterson wrote:
> The newly introduced ahci_platform_shutdown() method is called during
> system shutdown to disable host controller DMA and interrupts in order
> to avoid potentially corrupting or otherwise interfering with a new
> kernel being started with kexec.
>
> Signed-off-by: Nate Watterson <[email protected]>

Applied to libata/for-4.14.

Thanks.

--
tejun