From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [PATCH v2 3/7] of/irq: Break out msi-map lookup (again) Date: Tue, 14 Jun 2016 19:12:46 +0100 Message-ID: <5760491E.7060104@arm.com> References: <2cbffa9a341edfd10114994f6486f6b08d0c390c.1464966939.git.robin.murphy@arm.com> <20160614143750.GJ19407@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160614143750.GJ19407-5wv7dgnIgG8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Will Deacon Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Marc Zyngier , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On 14/06/16 15:37, Will Deacon wrote: > On Fri, Jun 03, 2016 at 06:15:38PM +0100, Robin Murphy wrote: >> The PCI msi-map code is already doing double-duty translating IDs and >> retrieving MSI parents, which unsurprisingly is the same functionality >> we need for the identically-formatted PCI iommu-map property. Drag the >> core parsing routine up yet another layer into the general OF-PCI code, >> and further generalise it for either kind of lookup in either flavour >> of map property. >> >> CC: Rob Herring >> CC: Frank Rowand >> CC: Marc Zyngier >> Signed-off-by: Robin Murphy >> --- >> >> v2: No change. >> >> drivers/of/irq.c | 70 ++------------------------------- >> drivers/of/of_pci.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++ >> include/linux/of_pci.h | 8 ++++ >> 3 files changed, 114 insertions(+), 66 deletions(-) > > [...] > >> diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c >> index 13f4fed38048..20bf5a0c57fd 100644 >> --- a/drivers/of/of_pci.c >> +++ b/drivers/of/of_pci.c >> @@ -306,3 +306,105 @@ struct msi_controller *of_pci_find_msi_chip_by_node(struct device_node *of_node) >> EXPORT_SYMBOL_GPL(of_pci_find_msi_chip_by_node); >> >> #endif /* CONFIG_PCI_MSI */ >> + >> +#define MASK_NAME_LEN 32 /* Safely longer than "iommu-map-mask" */ >> + >> +/** >> + * of_pci_map_rid - Translate a requester ID through a downstream mapping. >> + * @np: root complex device node. >> + * @map_name: property name of the map to use. >> + * @target: optional pointer to a target device node. >> + * @id_out: optional pointer to receive the translated ID. >> + * >> + * Given a PCI requester ID, look up the appropriate implementation-defined >> + * platform ID and/or the target device which receives transactions on that >> + * ID, as per the "iommu-map" and "msi-map" bindings. @target or @id_out may >> + * be NULL if not required. If @target points to a device node pointer, only >> + * entries targeting that node will be matched; if it points to a NULL >> + * value, it will receive the device node for the first matching target entry, >> + * with a reference held. >> + * >> + * Return: 0 on success or a standard error code on failure. >> + */ >> +int of_pci_map_rid(struct device_node *np, const char *map_name, u32 rid_in, >> + struct device_node **target, u32 *rid_out) >> +{ >> + u32 map_mask, masked_rid; >> + int map_len; >> + const __be32 *map = NULL; >> + char mask_name[MASK_NAME_LEN]; > > Couldn't you avoid this if you just took const char *mask_name as a > parameter too? Having started out with that, I considered two strings essentially duplicating each other, possibly duplicated per callsite, and thought it might be prudent to trade off a little runtime work for a permanent reduction in static data. I like the "never save anything you can recalculate" philosophy, but it is possible I got a bit carried away here. If you hate it I can just add the extra argument back. Robin. > > Will >