Re: [PATCH] libata: ahci enclosure management bios workaround

[David Milburn <dmilburn@redhat.com>]

David Milburn wrote:
> During driver initialization ahci_start_port may not be able
> to turn LEDs off because the hardware may still be transmitting
> a message. And since the BIOS may not be setting the LEDs to an
> off state when the controller is configured in AHCI mode, the
> drive LEDs may end up in a fault state. This patch will check
> to see if the controller is setup in AHCI mode and wait for
> the EM transmit bit to clear if needed during driver initialization.

Please drop this patch, we are looking at not setting ATA_FLAG_EM
if the controller is configured in AHCI mode.

Thanks,
David

> 
> Signed-off-by: David Milburn <dmilburn@redhat.com>
> ---
>  drivers/ata/ahci.c |   42 ++++++++++++++++++++++++++++++++++++++++--
>  1 files changed, 40 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
> index 788bba2..4694712 100644
> --- a/drivers/ata/ahci.c
> +++ b/drivers/ata/ahci.c
> @@ -78,6 +78,7 @@ static ssize_t ahci_led_store(struct ata_port *ap, const char *buf,
>  static ssize_t ahci_transmit_led_message(struct ata_port *ap, u32 state,
>  					ssize_t size);
>  #define MAX_SLOTS 8
> +#define MAX_RETRY 15
>  
>  enum {
>  	AHCI_PCI_BAR		= 5,
> @@ -218,6 +219,7 @@ enum {
>  	AHCI_HFLAG_NO_HOTPLUG		= (1 << 7), /* ignore PxSERR.DIAG.N */
>  	AHCI_HFLAG_SECT255		= (1 << 8), /* max 255 sectors */
>  	AHCI_HFLAG_YES_NCQ		= (1 << 9), /* force NCQ cap on */
> +	AHCI_HFLAG_BIOS_WORKAROUND      = (1 << 10), /* EM ahci mode */
>  
>  	/* ap->flags bits */
>  
> @@ -226,6 +228,8 @@ enum {
>  					  ATA_FLAG_ACPI_SATA | ATA_FLAG_AN |
>  					  ATA_FLAG_IPM,
>  
> +	SCC_REG                         = 0x0A, /* Sub Class Code Register */
> +	AHCI_MODE                       = 0x06, /* AHCI mode */
>  	ICH_MAP				= 0x90, /* ICH MAP register */
>  
>  	/* em_ctl bits */
> @@ -322,6 +326,7 @@ static ssize_t ahci_activity_show(struct ata_device *dev, char *buf);
>  static ssize_t ahci_activity_store(struct ata_device *dev,
>  				   enum sw_activity val);
>  static void ahci_init_sw_activity(struct ata_link *link);
> +static int ahci_ems_bios_workaround(struct pci_dev *pdev);
>  
>  static struct device_attribute *ahci_shost_attrs[] = {
>  	&dev_attr_link_power_management_policy,
> @@ -1115,6 +1120,9 @@ static void ahci_start_port(struct ata_port *ap)
>  	struct ahci_port_priv *pp = ap->private_data;
>  	struct ata_link *link;
>  	struct ahci_em_priv *emp;
> +	struct ahci_host_priv *hpriv = ap->host->private_data;
> +	ssize_t rc;
> +	int i;
>  
>  	/* enable FIS reception */
>  	ahci_start_fis_rx(ap);
> @@ -1126,7 +1134,16 @@ static void ahci_start_port(struct ata_port *ap)
>  	if (ap->flags & ATA_FLAG_EM) {
>  		ata_for_each_link(link, ap, EDGE) {
>  			emp = &pp->em_priv[link->pmp];
> -			ahci_transmit_led_message(ap, emp->led_state, 4);
> +			if (hpriv->flags & AHCI_HFLAG_BIOS_WORKAROUND) {
> +				for (i = 0; i < MAX_RETRY; i++) {
> +					rc = ahci_transmit_led_message(ap, emp->led_state, 4);
> +					if (rc == -EBUSY)
> +						udelay(100);
> +					else
> +						break;
> +				}
> +			} else
> +				ahci_transmit_led_message(ap, emp->led_state, 4);
>  		}
>  	}
>  
> @@ -1331,7 +1348,7 @@ static ssize_t ahci_transmit_led_message(struct ata_port *ap, u32 state,
>  	em_ctl = readl(mmio + HOST_EM_CTL);
>  	if (em_ctl & EM_CTL_TM) {
>  		spin_unlock_irqrestore(ap->lock, flags);
> -		return -EINVAL;
> +		return -EBUSY;
>  	}
>  
>  	/*
> @@ -2553,6 +2570,23 @@ static void ahci_p5wdh_workaround(struct ata_host *host)
>  	}
>  }
>  
> +static int ahci_ems_bios_workaround(struct pci_dev *pdev)
> +{
> +	u8 tmp;
> +
> +	/* Transmit bit may still be busy in AHCI mode */
> +	if (pdev->vendor == PCI_VENDOR_ID_INTEL && pdev->device >= 0x2821) {
> +		pci_read_config_byte(pdev, SCC_REG, &tmp);
> +
> +		if (tmp & AHCI_MODE)
> +			return 1;
> +		else
> +			return 0;
> +	}
> +
> +	return 0;
> +}
> +
>  static bool ahci_broken_system_poweroff(struct pci_dev *pdev)
>  {
>  	static const struct dmi_system_id broken_systems[] = {
> @@ -2656,6 +2690,10 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
>  	if (board_id == board_ahci_sb700 && pdev->revision >= 0x40)
>  		hpriv->flags &= ~AHCI_HFLAG_IGN_SERR_INTERNAL;
>  
> +	/* Enclosure management transmit bit maybe busy during driver init */
> +	if (ahci_ems_bios_workaround(pdev))
> +		hpriv->flags |= AHCI_HFLAG_BIOS_WORKAROUND;
> +
>  	if (!(hpriv->flags & AHCI_HFLAG_NO_MSI))
>  		pci_enable_msi(pdev);
>  
> --
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