Support for PCI Express reset type in EEH
Mike Mason
mmlnx at us.ibm.com
Thu Jul 16 04:32:49 EST 2009
This patch was simultaneously submitted to Red Hat for review. As a result of that review, I'm withdrawing this patch and will submit a new version shortly.
Mike
Mike Mason wrote:
> By default, EEH does what's known as a "hot reset" during error recovery
> of a PCI Express device. We've found a case where the device needs a
> "fundamental reset" to recover properly. The current PCI error recovery
> and EEH frameworks do not support this distinction.
>
> The attached patch (courtesy of Richard Lary) implements a reset type
> callback that can be used to determine what type of reset a device
> requires. It is backwards compatible with all other drivers that
> implement PCI error recovery callbacks. Only drivers that require a
> fundamental reset need to be changed. So far we're only aware of one
> driver that has the requirement (qla2xxx). The patch touches mostly EEH
> and pseries code, but does require a couple of minor additions to the
> overall PCI error recovery framework.
>
> Signed-off-by: Mike Mason <mmlnx at us.ibm.com>
>
> --- a/arch/powerpc/include/asm/ppc-pci.h 2009-06-09
> 20:05:27.000000000 -0700
> +++ b/arch/powerpc/include/asm/ppc-pci.h 2009-07-13
> 16:12:31.000000000 -0700
> @@ -90,7 +90,9 @@ int rtas_pci_enable(struct pci_dn *pdn,
> *
> * Returns a non-zero value if the reset failed.
> */
> -int rtas_set_slot_reset (struct pci_dn *);
> +#define HOT_RESET 1
> +#define FUNDAMENTAL_RESET 3
> +int rtas_set_slot_reset (struct pci_dn *, int reset_type);
> int eeh_wait_for_slot_status(struct pci_dn *pdn, int max_wait_msecs);
>
> /** --- a/arch/powerpc/platforms/pseries/eeh.c 2009-06-09
> 20:05:27.000000000 -0700
> +++ b/arch/powerpc/platforms/pseries/eeh.c 2009-07-13
> 16:27:27.000000000 -0700
> @@ -666,7 +666,7 @@ rtas_pci_enable(struct pci_dn *pdn, int
> /**
> * rtas_pci_slot_reset - raises/lowers the pci #RST line
> * @pdn pci device node
> - * @state: 1/0 to raise/lower the #RST
> + * @state: 1/3/0 to raise hot-reset/fundamental-reset/lower the #RST
> *
> * Clear the EEH-frozen condition on a slot. This routine
> * asserts the PCI #RST line if the 'state' argument is '1',
> @@ -742,9 +742,9 @@ int pcibios_set_pcie_reset_state(struct
> * Return 0 if success, else a non-zero value.
> */
>
> -static void __rtas_set_slot_reset(struct pci_dn *pdn)
> +static void __rtas_set_slot_reset(struct pci_dn *pdn, int reset_type)
> {
> - rtas_pci_slot_reset (pdn, 1);
> + rtas_pci_slot_reset (pdn, reset_type);
>
> /* The PCI bus requires that the reset be held high for at least
> * a 100 milliseconds. We wait a bit longer 'just in case'. */
> @@ -766,13 +766,13 @@ static void __rtas_set_slot_reset(struct
> msleep (PCI_BUS_SETTLE_TIME_MSEC);
> }
>
> -int rtas_set_slot_reset(struct pci_dn *pdn)
> +int rtas_set_slot_reset(struct pci_dn *pdn, int reset_type)
> {
> int i, rc;
>
> /* Take three shots at resetting the bus */
> for (i=0; i<3; i++) {
> - __rtas_set_slot_reset(pdn);
> + __rtas_set_slot_reset(pdn, reset_type);
>
> rc = eeh_wait_for_slot_status(pdn, PCI_BUS_RESET_WAIT_MSEC);
> if (rc == 0)
> --- a/arch/powerpc/platforms/pseries/eeh_driver.c 2009-07-13
> 14:25:24.000000000 -0700
> +++ b/arch/powerpc/platforms/pseries/eeh_driver.c 2009-07-13
> 16:39:16.000000000 -0700
> @@ -115,6 +115,34 @@ static void eeh_enable_irq(struct pci_de
>
> /* ------------------------------------------------------- */
> /**
> + * eeh_query_reset_type - query each device driver for reset type
> + *
> + * Query each device driver for special reset type if required
> + * merge the device driver responses. Cumulative response
> + * passed back in "userdata".
> + */
> +
> +static int eeh_query_reset_type(struct pci_dev *dev, void *userdata)
> +{
> + enum pci_ers_result rc, *res = userdata;
> + struct pci_driver *driver = dev->driver;
> +
> + if (!driver)
> + return 0;
> +
> + if (!driver->err_handler ||
> + !driver->err_handler->reset_type)
> + return 0;
> +
> + rc = driver->err_handler->reset_type (dev);
> +
> + /* A driver that needs a special reset trumps all others */
> + if (rc == PCI_ERS_RESULT_FUNDAMENTAL_RESET ) *res = rc;
> +
> + return 0;
> +}
> +
> +/**
> * eeh_report_error - report pci error to each device driver
> * * Report an EEH error to each device driver, collect up and @@ -282,9
> +310,12 @@ static int eeh_report_failure(struct pci
> * @pe_dn: pointer to a "Partionable Endpoint" device node.
> * This is the top-level structure on which pci
> * bus resets can be performed.
> + *
> + * reset_type: some devices may require type other than default hot reset.
> */
>
> -static int eeh_reset_device (struct pci_dn *pe_dn, struct pci_bus *bus)
> +static int eeh_reset_device (struct pci_dn *pe_dn, struct pci_bus *bus,
> + int reset_type)
> {
> struct device_node *dn;
> int cnt, rc;
> @@ -298,7 +329,7 @@ static int eeh_reset_device (struct pci_
> /* Reset the pci controller. (Asserts RST#; resets config space).
> * Reconfigure bridges and devices. Don't try to bring the system
> * up if the reset failed for some reason. */
> - rc = rtas_set_slot_reset(pe_dn);
> + rc = rtas_set_slot_reset(pe_dn, reset_type);
> if (rc)
> return rc;
>
> @@ -343,6 +374,7 @@ struct pci_dn * handle_eeh_events (struc
> struct pci_dn *frozen_pdn;
> struct pci_bus *frozen_bus;
> int rc = 0;
> + int reset_type = HOT_RESET;
> enum pci_ers_result result = PCI_ERS_RESULT_NONE;
> const char *location, *pci_str, *drv_str;
>
> @@ -400,10 +432,16 @@ struct pci_dn * handle_eeh_events (struc
>
> /* Walk the various device drivers attached to this slot through
> * a reset sequence, giving each an opportunity to do what it needs
> - * to accomplish the reset. Each child gets a report of the
> - * status ... if any child can't handle the reset, then the entire
> - * slot is dlpar removed and added.
> + * to accomplish the reset. Query device driver for special reset
> + * requiements. Report eeh error to each child with cumulative
> + * result status... if any child can't handle the reset,
> + * then the entire slot is dlpar removed and added.
> */
> + pci_walk_bus(frozen_bus, eeh_query_reset_type, &result);
> + if ( result == PCI_ERS_RESULT_FUNDAMENTAL_RESET )
> + reset_type = FUNDAMENTAL_RESET;
> +
> + result = PCI_ERS_RESULT_NONE;
> pci_walk_bus(frozen_bus, eeh_report_error, &result);
>
> /* Get the current PCI slot state. This can take a long time,
> @@ -425,7 +463,8 @@ struct pci_dn * handle_eeh_events (struc
> * go down willingly, without panicing the system.
> */
> if (result == PCI_ERS_RESULT_NONE) {
> - rc = eeh_reset_device(frozen_pdn, frozen_bus);
> + rc = eeh_reset_device(frozen_pdn, frozen_bus, reset_type);
> +
> if (rc) {
> printk(KERN_WARNING "EEH: Unable to reset, rc=%d\n", rc);
> goto hard_fail;
> @@ -466,7 +505,7 @@ struct pci_dn * handle_eeh_events (struc
>
> /* If any device called out for a reset, then reset the slot */
> if (result == PCI_ERS_RESULT_NEED_RESET) {
> - rc = eeh_reset_device(frozen_pdn, NULL);
> + rc = eeh_reset_device(frozen_pdn, NULL, reset_type);
> if (rc) {
> printk(KERN_WARNING "EEH: Cannot reset, rc=%d\n", rc);
> goto hard_fail;
> --- a/include/linux/pci.h 2009-07-13 14:25:37.000000000 -0700
> +++ b/include/linux/pci.h 2009-07-13 16:12:31.000000000 -0700
> @@ -446,6 +446,9 @@ enum pci_ers_result {
>
> /* Device driver is fully recovered and operational */
> PCI_ERS_RESULT_RECOVERED = (__force pci_ers_result_t) 5,
> +
> + /* Device driver requires fundamental reset to recover */
> + PCI_ERS_RESULT_FUNDAMENTAL_RESET = (__force pci_ers_result_t) 6,
> };
>
> /* PCI bus error event callbacks */
> @@ -465,6 +468,9 @@ struct pci_error_handlers {
>
> /* Device driver may resume normal operations */
> void (*resume)(struct pci_dev *dev);
> +
> + /* PCI slot requires special reset type for recovery */
> + pci_ers_result_t (*reset_type)(struct pci_dev *dev);
> };
>
> /* ---------------------------------------------------------------- */
> --- a/arch/powerpc/include/asm/ppc-pci.h 2009-06-09
> 20:05:27.000000000 -0700
> +++ b/arch/powerpc/include/asm/ppc-pci.h 2009-07-13
> 16:12:31.000000000 -0700
> @@ -90,7 +90,9 @@ int rtas_pci_enable(struct pci_dn *pdn,
> *
> * Returns a non-zero value if the reset failed.
> */
> -int rtas_set_slot_reset (struct pci_dn *);
> +#define HOT_RESET 1
> +#define FUNDAMENTAL_RESET 3
> +int rtas_set_slot_reset (struct pci_dn *, int reset_type);
> int eeh_wait_for_slot_status(struct pci_dn *pdn, int max_wait_msecs);
>
> /** --- a/arch/powerpc/platforms/pseries/eeh.c 2009-06-09
> 20:05:27.000000000 -0700
> +++ b/arch/powerpc/platforms/pseries/eeh.c 2009-07-13
> 16:27:27.000000000 -0700
> @@ -666,7 +666,7 @@ rtas_pci_enable(struct pci_dn *pdn, int
> /**
> * rtas_pci_slot_reset - raises/lowers the pci #RST line
> * @pdn pci device node
> - * @state: 1/0 to raise/lower the #RST
> + * @state: 1/3/0 to raise hot-reset/fundamental-reset/lower the #RST
> *
> * Clear the EEH-frozen condition on a slot. This routine
> * asserts the PCI #RST line if the 'state' argument is '1',
> @@ -742,9 +742,9 @@ int pcibios_set_pcie_reset_state(struct
> * Return 0 if success, else a non-zero value.
> */
>
> -static void __rtas_set_slot_reset(struct pci_dn *pdn)
> +static void __rtas_set_slot_reset(struct pci_dn *pdn, int reset_type)
> {
> - rtas_pci_slot_reset (pdn, 1);
> + rtas_pci_slot_reset (pdn, reset_type);
>
> /* The PCI bus requires that the reset be held high for at least
> * a 100 milliseconds. We wait a bit longer 'just in case'. */
> @@ -766,13 +766,13 @@ static void __rtas_set_slot_reset(struct
> msleep (PCI_BUS_SETTLE_TIME_MSEC);
> }
>
> -int rtas_set_slot_reset(struct pci_dn *pdn)
> +int rtas_set_slot_reset(struct pci_dn *pdn, int reset_type)
> {
> int i, rc;
>
> /* Take three shots at resetting the bus */
> for (i=0; i<3; i++) {
> - __rtas_set_slot_reset(pdn);
> + __rtas_set_slot_reset(pdn, reset_type);
>
> rc = eeh_wait_for_slot_status(pdn, PCI_BUS_RESET_WAIT_MSEC);
> if (rc == 0)
> --- a/arch/powerpc/platforms/pseries/eeh_driver.c 2009-07-13
> 14:25:24.000000000 -0700
> +++ b/arch/powerpc/platforms/pseries/eeh_driver.c 2009-07-13
> 16:39:16.000000000 -0700
> @@ -115,6 +115,34 @@ static void eeh_enable_irq(struct pci_de
>
> /* ------------------------------------------------------- */
> /**
> + * eeh_query_reset_type - query each device driver for reset type
> + *
> + * Query each device driver for special reset type if required
> + * merge the device driver responses. Cumulative response
> + * passed back in "userdata".
> + */
> +
> +static int eeh_query_reset_type(struct pci_dev *dev, void *userdata)
> +{
> + enum pci_ers_result rc, *res = userdata;
> + struct pci_driver *driver = dev->driver;
> +
> + if (!driver)
> + return 0;
> +
> + if (!driver->err_handler ||
> + !driver->err_handler->reset_type)
> + return 0;
> +
> + rc = driver->err_handler->reset_type (dev);
> +
> + /* A driver that needs a special reset trumps all others */
> + if (rc == PCI_ERS_RESULT_FUNDAMENTAL_RESET ) *res = rc;
> +
> + return 0;
> +}
> +
> +/**
> * eeh_report_error - report pci error to each device driver
> * * Report an EEH error to each device driver, collect up and @@ -282,9
> +310,12 @@ static int eeh_report_failure(struct pci
> * @pe_dn: pointer to a "Partionable Endpoint" device node.
> * This is the top-level structure on which pci
> * bus resets can be performed.
> + *
> + * reset_type: some devices may require type other than default hot reset.
> */
>
> -static int eeh_reset_device (struct pci_dn *pe_dn, struct pci_bus *bus)
> +static int eeh_reset_device (struct pci_dn *pe_dn, struct pci_bus *bus,
> + int reset_type)
> {
> struct device_node *dn;
> int cnt, rc;
> @@ -298,7 +329,7 @@ static int eeh_reset_device (struct pci_
> /* Reset the pci controller. (Asserts RST#; resets config space).
> * Reconfigure bridges and devices. Don't try to bring the system
> * up if the reset failed for some reason. */
> - rc = rtas_set_slot_reset(pe_dn);
> + rc = rtas_set_slot_reset(pe_dn, reset_type);
> if (rc)
> return rc;
>
> @@ -343,6 +374,7 @@ struct pci_dn * handle_eeh_events (struc
> struct pci_dn *frozen_pdn;
> struct pci_bus *frozen_bus;
> int rc = 0;
> + int reset_type = HOT_RESET;
> enum pci_ers_result result = PCI_ERS_RESULT_NONE;
> const char *location, *pci_str, *drv_str;
>
> @@ -400,10 +432,16 @@ struct pci_dn * handle_eeh_events (struc
>
> /* Walk the various device drivers attached to this slot through
> * a reset sequence, giving each an opportunity to do what it needs
> - * to accomplish the reset. Each child gets a report of the
> - * status ... if any child can't handle the reset, then the entire
> - * slot is dlpar removed and added.
> + * to accomplish the reset. Query device driver for special reset
> + * requiements. Report eeh error to each child with cumulative
> + * result status... if any child can't handle the reset,
> + * then the entire slot is dlpar removed and added.
> */
> + pci_walk_bus(frozen_bus, eeh_query_reset_type, &result);
> + if ( result == PCI_ERS_RESULT_FUNDAMENTAL_RESET )
> + reset_type = FUNDAMENTAL_RESET;
> +
> + result = PCI_ERS_RESULT_NONE;
> pci_walk_bus(frozen_bus, eeh_report_error, &result);
>
> /* Get the current PCI slot state. This can take a long time,
> @@ -425,7 +463,8 @@ struct pci_dn * handle_eeh_events (struc
> * go down willingly, without panicing the system.
> */
> if (result == PCI_ERS_RESULT_NONE) {
> - rc = eeh_reset_device(frozen_pdn, frozen_bus);
> + rc = eeh_reset_device(frozen_pdn, frozen_bus, reset_type);
> +
> if (rc) {
> printk(KERN_WARNING "EEH: Unable to reset, rc=%d\n", rc);
> goto hard_fail;
> @@ -466,7 +505,7 @@ struct pci_dn * handle_eeh_events (struc
>
> /* If any device called out for a reset, then reset the slot */
> if (result == PCI_ERS_RESULT_NEED_RESET) {
> - rc = eeh_reset_device(frozen_pdn, NULL);
> + rc = eeh_reset_device(frozen_pdn, NULL, reset_type);
> if (rc) {
> printk(KERN_WARNING "EEH: Cannot reset, rc=%d\n", rc);
> goto hard_fail;
> --- a/include/linux/pci.h 2009-07-13 14:25:37.000000000 -0700
> +++ b/include/linux/pci.h 2009-07-13 16:12:31.000000000 -0700
> @@ -446,6 +446,9 @@ enum pci_ers_result {
>
> /* Device driver is fully recovered and operational */
> PCI_ERS_RESULT_RECOVERED = (__force pci_ers_result_t) 5,
> +
> + /* Device driver requires fundamental reset to recover */
> + PCI_ERS_RESULT_FUNDAMENTAL_RESET = (__force pci_ers_result_t) 6,
> };
>
> /* PCI bus error event callbacks */
> @@ -465,6 +468,9 @@ struct pci_error_handlers {
>
> /* Device driver may resume normal operations */
> void (*resume)(struct pci_dev *dev);
> +
> + /* PCI slot requires special reset type for recovery */
> + pci_ers_result_t (*reset_type)(struct pci_dev *dev);
> };
>
> /* ---------------------------------------------------------------- */
>
>
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