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powerpc/powernv: Add ppc_pci_reset_phbs parameter to issue a PHB reset

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During a kdump kernel boot in PowerPC, we request a reset of the PHBs
to the FW. It makes sense, since if we are booting a kdump kernel it
means we had some trouble before and we cannot rely in the adapters'
health; they could be in a bad state, hence the reset is needed.

But this reset is useful not only in kdump - there are situations,
specially when debugging drivers, that we could break an adapter in
a way it requires such reset. One can tell to just go ahead and
reboot the machine, but happens that many times doing kexec is much
faster, and so preferable than a full power cycle.

This patch adds the ppc_pci_reset_phbs parameter to perform such reset.

Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Guilherme G. Piccoli 2017-11-17 16:58:59 -02:00 committed by Michael Ellerman
parent 7339390d77
commit 45baee1416
1 changed files with 12 additions and 2 deletions
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14
arch/powerpc/platforms/powernv/pci-ioda.c
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@ -89,6 +89,7 @@ void pe_level_printk(const struct pnv_ioda_pe *pe, const char *level,
}
static bool pnv_iommu_bypass_disabled __read_mostly;
static bool pci_reset_phbs __read_mostly;
static int __init iommu_setup(char *str)
{
@ -110,6 +111,14 @@ static int __init iommu_setup(char *str)
}
early_param("iommu", iommu_setup);
static int __init pci_reset_phbs_setup(char *str)
{
pci_reset_phbs = true;
return 0;
}
early_param("ppc_pci_reset_phbs", pci_reset_phbs_setup);
static inline bool pnv_pci_is_m64(struct pnv_phb *phb, struct resource *r)
{
/*
@ -4033,9 +4042,10 @@ static void __init pnv_pci_init_ioda_phb(struct device_node *np,
* If we're running in kdump kernel, the previous kernel never
* shutdown PCI devices correctly. We already got IODA table
* cleaned out. So we have to issue PHB reset to stop all PCI
* transactions from previous kernel.
* transactions from previous kernel. The ppc_pci_reset_phbs
* kernel parameter will force this reset too.
*/
if (is_kdump_kernel()) {
if (is_kdump_kernel() || pci_reset_phbs) {
pr_info(" Issue PHB reset ...\n");
pnv_eeh_phb_reset(hose, EEH_RESET_FUNDAMENTAL);
pnv_eeh_phb_reset(hose, EEH_RESET_DEACTIVATE);