kernel/linux.git/arch/powerpc/include/asm/eeh.h, branch v6.7

powerpc/eeh: Remove unused inline functions

2022-05-04T11:44:02+00:00

pseries_eeh_init_edev() is used exclusively in eeh_pseries.c, make it static and remove unused inline function. pseries_eeh_init_edev_recursive() is only called from files build wich CONFIG_HOTPLUG_PCI_RPA which depends on CONFIG_PSERIES and CONFIG_EEH, so can remove the unused inline version. Suggested-by: Christophe Leroy Signed-off-by: YueHaibing Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220316104239.26508-1-yuehaibing@huawei.com

powerpc/eeh: Remove unused inline function eeh_dev_phb_init_dynamic()

2022-05-04T09:37:43+00:00

commit 475028efc708 ("powerpc/eeh: Remove eeh_dev_phb_init_dynamic()") left behind this, so can remove it. Signed-off-by: YueHaibing Reviewed-by: Daniel Axtens Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210324140714.19612-1-yuehaibing@huawei.com

powerpc/kernel: Add __init attribute to eligible functions

2021-12-23T11:33:10+00:00

Some functions defined in `arch/powerpc/kernel` (and one in `arch/powerpc/ kexec`) are deserving of an `__init` macro attribute. These functions are only called by other initialization functions and therefore should inherit the attribute. Also, change function declarations in header files to include `__init`. Signed-off-by: Nick Child Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211216220035.605465-2-nick.child@ibm.com

powerpc/eeh: Delete eeh_pe->config_addr

2020-10-07T11:34:47+00:00

The eeh_pe->config_addr field was supposed to be removed in commit 35d64734b643 ("powerpc/eeh: Clean up PE addressing") which made it largely unused. Finish the job. Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20201007040903.819081-1-oohall@gmail.com

powerpc/eeh: Clean up PE addressing

2020-10-06T12:22:25+00:00

When support for EEH on PowerNV was added a lot of pseries specific code was made "generic" and some of the quirks of pseries EEH came along for the ride. One of the stranger quirks is eeh_pe containing two types of PE address: pe->addr and pe->config_addr. There reason for this appears to be historical baggage rather than any real requirements. On pseries EEH PEs are manipulated using RTAS calls. Each EEH RTAS call takes a "PE configuration address" as an input which is used to identify which EEH PE is being manipulated by the call. When initialising the EEH state for a device the first thing we need to do is determine the configuration address for the PE which contains the device so we can enable EEH on that PE. This process is outlined in PAPR which is the modern (i.e post-2003) FW specification for pseries. However, EEH support was first described in the pSeries RISC Platform Architecture (RPA) and although they are mostly compatible EEH is one of the areas where they are not. The major difference is that RPA doesn't actually have the concept of a PE. On RPA systems the EEH RTAS calls are done on a per-device basis using the same config_addr that would be passed to the RTAS functions to access PCI config space (e.g. ibm,read-pci-config). The config_addr is not identical since the function and config register offsets of the config_addr must be set to zero. EEH operations being done on a per-device basis doesn't make a whole lot of sense when you consider how EEH was implemented on legacy PCI systems. For legacy PCI(-X) systems EEH was implemented using special PCI-PCI bridges which contained logic to detect errors and freeze the secondary bus when one occurred. This means that the EEH enabled state is shared among all devices behind that EEH bridge. As a result there's no way to implement the per-device control required for the semantics specified by RPA. It can be made to work if we assume that a separate EEH bridge exists for each EEH capable PCI slot and there are no bridges behind those slots. However, RPA also specifies the ibm,configure-bridge RTAS call for re-initalising bridges behind EEH capable slots after they are reset due to an EEH event so that is probably not a valid assumption. This incoherence was fixed in later PAPR, which succeeded RPA. Unfortunately, since Linux EEH support seems to have been implemented based on the RPA spec some of the legacy assumptions were carried over (probably for POWER4 compatibility). The fix made in PAPR was the introduction of the "PE" concept and redefining the EEH RTAS calls (set-eeh-option, reset-slot, etc) to operate on a per-PE basis so all devices behind an EEH bride would share the same EEH state. The "config_addr" argument to the EEH RTAS calls became the "PE_config_addr" and the OS was required to use the ibm,get-config-addr-info RTAS call to find the correct PE address for the device. When support for the new interfaces was added to Linux it was implemented using something like: At probe time: pdn->eeh_config_addr = rtas_config_addr(pdn); pdn->eeh_pe_config_addr = rtas_get_config_addr_info(pdn); When performing an RTAS call: config_addr = pdn->eeh_config_addr; if (pdn->eeh_pe_config_addr) config_addr = pdn->eeh_pe_config_addr; rtas_call(..., config_addr, ...); In other words, if the ibm,get-config-addr-info RTAS call is implemented and returned a valid result we'd use that as the argument to the EEH RTAS calls. If not, Linux would fall back to using the device's config_addr. Over time these addresses have moved around going from pci_dn to eeh_dev and finally into eeh_pe. Today the users look like this: config_addr = pe->config_addr; if (pe->addr) config_addr = pe->addr; rtas_call(..., config_addr, ...); However, considering the EEH core always operates on a per-PE basis and even on pseries the only per-device operation is the initial call to ibm,set-eeh-option I'm not sure if any of this actually works on an RPA system today. It doesn't make much sense to have the fallback address in a generic structure either since the bulk of the code which reference it is in pseries anyway. The EEH core makes a token effort to support looking up a PE using the config_addr by having two arguments to eeh_pe_get(). However, a survey of all the callers to eeh_pe_get() shows that all bar one have the config_addr argument hard-coded to zero.The only caller that doesn't is in eeh_pe_tree_insert() which has: if (!eeh_has_flag(EEH_VALID_PE_ZERO) && !edev->pe_config_addr) return -EINVAL; pe = eeh_pe_get(hose, edev->pe_config_addr, edev->bdfn); The third argument (config_addr) is only used if the second (pe->addr) argument is invalid. The preceding check ensures that the call to eeh_pe_get() will never happen if edev->pe_config_addr is invalid so there is no situation where eeh_pe_get() will search for a PE based on the 3rd argument. The check also means that we'll never insert a PE into the tree where pe_config_addr is zero since EEH_VALID_PE_ZERO is never set on pseries. All the users of the fallback address on pseries never actually use the fallback and all the only caller that supplies something for the config_addr argument to eeh_pe_get() never use it either. It's all dead code. This patch removes the fallback address from eeh_pe since nothing uses it. Specificly, we do this by: 1) Removing pe->config_addr 2) Removing the EEH_VALID_PE_ZERO flag 3) Removing the fallback address argument to eeh_pe_get(). 4) Removing all the checks for pe->addr being zero in the pseries EEH code. This leaves us with PE's only being identified by what's in their pe->addr field and the EEH core relying on the platform to ensure that eeh_dev's are only inserted into the EEH tree if they're actually inside a PE. No functional changes, I hope. Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200918093050.37344-9-oohall@gmail.com

powerpc/eeh: Delete eeh_ops->init

2020-10-06T12:22:25+00:00

No longer used since the platforms perform their EEH initialisation before calling eeh_init(). Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200918093050.37344-4-oohall@gmail.com

powerpc/eeh: Rework EEH initialisation

2020-10-06T12:22:24+00:00

Drop the EEH register / unregister ops thing and have the platform pass the ops structure into eeh_init() directly. This takes one initcall out of the EEH setup path and it means we're only doing EEH setup on the platforms which actually support it. It's also less code and generally easier to follow. No functional changes. Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200918093050.37344-1-oohall@gmail.com

powerpc/eeh: Move PE tree setup into the platform

2020-07-26T13:34:21+00:00

The EEH core has a concept of a "PE tree" to support PowerNV. The PE tree follows the PCI bus structures because a reset asserted on an upstream bridge will be propagated to the downstream bridges. On pseries there's a 1-1 correspondence between what the guest sees are a PHB and a PE so the "tree" is really just a single node. Current the EEH core is reponsible for setting up this PE tree which it does by traversing the pci_dn tree. The structure of the pci_dn tree matches the bus tree on PowerNV which leads to the PE tree being "correct" this setup method doesn't make a whole lot of sense and it's actively confusing for the pseries case where it doesn't really do anything. We want to remove the dependence on pci_dn anyway so this patch move choosing where to insert a new PE into the platform code rather than being part of the generic EEH code. For PowerNV this simplifies the tree building logic and removes the use of pci_dn. For pseries we keep the existing logic. I'm not really convinced it does anything due to the 1-1 PE-to-PHB correspondence so every device under that PHB should be in the same PE, but I'd rather not remove it entirely until we've had a chance to look at it more deeply. Signed-off-by: Oliver O'Halloran Reviewed-by: Alexey Kardashevskiy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200725081231.39076-14-oohall@gmail.com

powerpc/eeh: Rename eeh_{add_to|remove_from}_parent_pe()

2020-07-26T13:34:21+00:00

The naming of eeh_{add_to|remove_from}_parent_pe() doesn't really reflect what they actually do. If the PE referred to be edev->pe_config_addr already exists under that PHB then the edev is added to that PE. However, if the PE doesn't exist the a new one is created for the edev. The bulk of the implementation of eeh_add_to_parent_pe() covers that second case. Similarly, most of eeh_remove_from_parent_pe() is determining when it's safe to delete a PE. Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200725081231.39076-12-oohall@gmail.com

powerpc/eeh: Remove class code field from edev

2020-07-26T13:34:21+00:00

The edev->class_code field is never referenced anywhere except for the platform specific probe functions. The same information is available in the pci_dev for PowerNV and in the pci_dn on pseries so we can remove the field. Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200725081231.39076-11-oohall@gmail.com