Commit 5a090f7c authored by Wen Xiong's avatar Wen Xiong Committed by Michael Ellerman
Browse files

powerpc/pseries: PCIE PHB reset 



Several device drivers hit EEH(Extended Error handling) when
triggering kdump on Pseries PowerVM. This patch implemented a reset of
the PHBs in pci general code when triggering kdump. PHB reset stop all
PCI transactions from normal kernel. We have tested the patch in
several enviroments:
  - direct slot adapters
  - adapters under the switch
  - a VF adapter in PowerVM
  - a VF adapter/adapter in KVM guest.

Signed-off-by: default avatarWen Xiong <wenxiong@linux.vnet.ibm.com>
[mpe: Fix broken whitespace, subject & SOB formatting]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1594651173-32166-1-git-send-email-wenxiong@linux.vnet.ibm.com
parent 2384b36f

arch/powerpc/platforms/pseries/eeh_pseries.c

+169 −63
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/sched.h>

#include <linux/seq_file.h>

#include <linux/spinlock.h>

#include <linux/crash_dump.h>



#include <asm/eeh.h>

#include <asm/eeh_event.h>
@@ -80,6 +81,152 @@ void pseries_pcibios_bus_add_device(struct pci_dev *pdev) 
	eeh_probe_device(pdev);

}





/**

 * pseries_eeh_get_config_addr - Retrieve config address

 *

 * Retrieve the assocated config address. Actually, there're 2 RTAS

 * function calls dedicated for the purpose. We need implement

 * it through the new function and then the old one. Besides,

 * you should make sure the config address is figured out from

 * FDT node before calling the function.

 *

 * It's notable that zero'ed return value means invalid PE config

 * address.

 */

static int pseries_eeh_get_config_addr(struct pci_controller *phb, int config_addr)

{

	int ret = 0;

	int rets[3];



	if (ibm_get_config_addr_info2 != RTAS_UNKNOWN_SERVICE) {

		/*

		 * First of all, we need to make sure there has one PE

		 * associated with the device. Otherwise, PE address is

		 * meaningless.

		 */

		ret = rtas_call(ibm_get_config_addr_info2, 4, 2, rets,

				config_addr, BUID_HI(phb->buid),

				BUID_LO(phb->buid), 1);

		if (ret || (rets[0] == 0))

			return 0;



		/* Retrieve the associated PE config address */

		ret = rtas_call(ibm_get_config_addr_info2, 4, 2, rets,

				config_addr, BUID_HI(phb->buid),

				BUID_LO(phb->buid), 0);

		if (ret) {

			pr_warn("%s: Failed to get address for PHB#%x-PE#%x\n",

				__func__, phb->global_number, config_addr);

			return 0;

		}



		return rets[0];

	}



	if (ibm_get_config_addr_info != RTAS_UNKNOWN_SERVICE) {

		ret = rtas_call(ibm_get_config_addr_info, 4, 2, rets,

				config_addr, BUID_HI(phb->buid),

				BUID_LO(phb->buid), 0);

		if (ret) {

			pr_warn("%s: Failed to get address for PHB#%x-PE#%x\n",

				__func__, phb->global_number, config_addr);

			return 0;

		}



		return rets[0];

	}



	return ret;

}



/**

 * pseries_eeh_phb_reset - Reset the specified PHB

 * @phb: PCI controller

 * @config_adddr: the associated config address

 * @option: reset option

 *

 * Reset the specified PHB/PE

 */

static int pseries_eeh_phb_reset(struct pci_controller *phb, int config_addr, int option)

{

	int ret;



	/* Reset PE through RTAS call */

	ret = rtas_call(ibm_set_slot_reset, 4, 1, NULL,

			config_addr, BUID_HI(phb->buid),

			BUID_LO(phb->buid), option);



	/* If fundamental-reset not supported, try hot-reset */

	if (option == EEH_RESET_FUNDAMENTAL &&

	    ret == -8) {

		option = EEH_RESET_HOT;

		ret = rtas_call(ibm_set_slot_reset, 4, 1, NULL,

				config_addr, BUID_HI(phb->buid),

				BUID_LO(phb->buid), option);

	}



	/* We need reset hold or settlement delay */

	if (option == EEH_RESET_FUNDAMENTAL ||

	    option == EEH_RESET_HOT)

		msleep(EEH_PE_RST_HOLD_TIME);

	else

		msleep(EEH_PE_RST_SETTLE_TIME);



	return ret;

}



/**

 * pseries_eeh_phb_configure_bridge - Configure PCI bridges in the indicated PE

 * @phb: PCI controller

 * @config_adddr: the associated config address

 *

 * The function will be called to reconfigure the bridges included

 * in the specified PE so that the mulfunctional PE would be recovered

 * again.

 */

static int pseries_eeh_phb_configure_bridge(struct pci_controller *phb, int config_addr)

{

	int ret;

	/* Waiting 0.2s maximum before skipping configuration */

	int max_wait = 200;



	while (max_wait > 0) {

		ret = rtas_call(ibm_configure_pe, 3, 1, NULL,

				config_addr, BUID_HI(phb->buid),

				BUID_LO(phb->buid));



		if (!ret)

			return ret;

		if (ret < 0)

			break;



		/*

		 * If RTAS returns a delay value that's above 100ms, cut it

		 * down to 100ms in case firmware made a mistake.  For more

		 * on how these delay values work see rtas_busy_delay_time

		 */

		if (ret > RTAS_EXTENDED_DELAY_MIN+2 &&

		    ret <= RTAS_EXTENDED_DELAY_MAX)

			ret = RTAS_EXTENDED_DELAY_MIN+2;



		max_wait -= rtas_busy_delay_time(ret);



		if (max_wait < 0)

			break;



		rtas_busy_delay(ret);

	}



	pr_warn("%s: Unable to configure bridge PHB#%x-PE#%x (%d)\n",

		__func__, phb->global_number, config_addr, ret);

	/* PAPR defines -3 as "Parameter Error" for this function: */

	if (ret == -3)

		return -EINVAL;

	else

		return -EIO;

}



/*

 * Buffer for reporting slot-error-detail rtas calls. Its here

 * in BSS, and not dynamically alloced, so that it ends up in
@@ -96,6 +243,10 @@ static int eeh_error_buf_size; 
 */

static int pseries_eeh_init(void)

{

	struct pci_controller *phb;

	struct pci_dn *pdn;

	int addr, config_addr;



	/* figure out EEH RTAS function call tokens */

	ibm_set_eeh_option		= rtas_token("ibm,set-eeh-option");

	ibm_set_slot_reset		= rtas_token("ibm,set-slot-reset");
@@ -148,6 +299,22 @@ static int pseries_eeh_init(void) 
	/* Set EEH machine dependent code */

	ppc_md.pcibios_bus_add_device = pseries_pcibios_bus_add_device;



	if (is_kdump_kernel() || reset_devices) {

		pr_info("Issue PHB reset ...\n");

		list_for_each_entry(phb, &hose_list, list_node) {

			pdn = list_first_entry(&PCI_DN(phb->dn)->child_list, struct pci_dn, list);

			addr = (pdn->busno << 16) | (pdn->devfn << 8);

			config_addr = pseries_eeh_get_config_addr(phb, addr);

			/* invalid PE config addr */

			if (config_addr == 0)

				continue;



			pseries_eeh_phb_reset(phb, config_addr, EEH_RESET_FUNDAMENTAL);

			pseries_eeh_phb_reset(phb, config_addr, EEH_RESET_DEACTIVATE);

			pseries_eeh_phb_configure_bridge(phb, config_addr);

		}

	}



	return 0;

}
@@ -569,35 +736,13 @@ static int pseries_eeh_get_state(struct eeh_pe *pe, int *delay) 
static int pseries_eeh_reset(struct eeh_pe *pe, int option)

{

	int config_addr;

	int ret;



	/* Figure out PE address */

	config_addr = pe->config_addr;

	if (pe->addr)

		config_addr = pe->addr;



	/* Reset PE through RTAS call */

	ret = rtas_call(ibm_set_slot_reset, 4, 1, NULL,

			config_addr, BUID_HI(pe->phb->buid),

			BUID_LO(pe->phb->buid), option);



	/* If fundamental-reset not supported, try hot-reset */

	if (option == EEH_RESET_FUNDAMENTAL &&

	    ret == -8) {

		option = EEH_RESET_HOT;

		ret = rtas_call(ibm_set_slot_reset, 4, 1, NULL,

				config_addr, BUID_HI(pe->phb->buid),

				BUID_LO(pe->phb->buid), option);

	}



	/* We need reset hold or settlement delay */

	if (option == EEH_RESET_FUNDAMENTAL ||

	    option == EEH_RESET_HOT)

		msleep(EEH_PE_RST_HOLD_TIME);

	else

		msleep(EEH_PE_RST_SETTLE_TIME);



	return ret;

	return pseries_eeh_phb_reset(pe->phb, config_addr, option);

}



/**
@@ -641,56 +786,17 @@ static int pseries_eeh_get_log(struct eeh_pe *pe, int severity, char *drv_log, u 
 * pseries_eeh_configure_bridge - Configure PCI bridges in the indicated PE

 * @pe: EEH PE

 *

 * The function will be called to reconfigure the bridges included

 * in the specified PE so that the mulfunctional PE would be recovered

 * again.

 */

static int pseries_eeh_configure_bridge(struct eeh_pe *pe)

{

	int config_addr;

	int ret;

	/* Waiting 0.2s maximum before skipping configuration */

	int max_wait = 200;



	/* Figure out the PE address */

	config_addr = pe->config_addr;

	if (pe->addr)

		config_addr = pe->addr;



	while (max_wait > 0) {

		ret = rtas_call(ibm_configure_pe, 3, 1, NULL,

				config_addr, BUID_HI(pe->phb->buid),

				BUID_LO(pe->phb->buid));



		if (!ret)

			return ret;

		if (ret < 0)

			break;



		/*

		 * If RTAS returns a delay value that's above 100ms, cut it

		 * down to 100ms in case firmware made a mistake.  For more

		 * on how these delay values work see rtas_busy_delay_time

		 */

		if (ret > RTAS_EXTENDED_DELAY_MIN+2 &&

		    ret <= RTAS_EXTENDED_DELAY_MAX)

			ret = RTAS_EXTENDED_DELAY_MIN+2;



		max_wait -= rtas_busy_delay_time(ret);



		if (max_wait < 0)

			break;



		rtas_busy_delay(ret);

	}



	pr_warn("%s: Unable to configure bridge PHB#%x-PE#%x (%d)\n",

		__func__, pe->phb->global_number, pe->addr, ret);

	/* PAPR defines -3 as "Parameter Error" for this function: */

	if (ret == -3)

		return -EINVAL;

	else

		return -EIO;

	return pseries_eeh_phb_configure_bridge(pe->phb, config_addr);

}



/**

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