Hi Arnd > -----Original Message----- > From: Arnd Bergmann [mailto:arnd@xxxxxxxx] > Sent: 25 November 2016 12:04 > To: Gabriele Paoloni > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; mark.rutland@xxxxxxx; > catalin.marinas@xxxxxxx; linux-pci@xxxxxxxxxxxxxxx; > liviu.dudau@xxxxxxx; Linuxarm; lorenzo.pieralisi@xxxxxxx; xuwei (O); > Jason Gunthorpe; T homas Petazzoni; linux-serial@xxxxxxxxxxxxxxx; > benh@xxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; minyard@xxxxxxx; > will.deacon@xxxxxxx; John Garry; olof@xxxxxxxxx; robh+dt@xxxxxxxxxx; > bhelgaas@go og le.com; kantyzc@xxxxxxx; zhichang.yuan 02@xxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; Yuanzhichang; zourongrong@xxxxxxxxx > Subject: Re: [PATCH V5 3/3] ARM64 LPC: LPC driver implementation on > Hip06 > > On Friday, November 25, 2016 8:46:11 AM CET Gabriele Paoloni wrote: > > > From: Arnd Bergmann [mailto:arnd@xxxxxxxx] > > > > > > On Wednesday, November 23, 2016 6:07:11 PM CET Arnd Bergmann wrote: > > > > On Wednesday, November 23, 2016 3:22:33 PM CET Gabriele Paoloni > > > wrote: > > > > > From: Arnd Bergmann [mailto:arnd@xxxxxxxx] > > > > > > On Friday, November 18, 2016 5:03:11 PM CET Gabriele Paoloni > > > /* > > > @@ -549,9 +548,14 @@ static int of_translate_one(struct device_node > > > *parent, struct of_bus *bus, > > > * that translation is impossible (that is we are not dealing with > a > > > value > > > * that can be mapped to a cpu physical address). This is not > really > > > specified > > > * that way, but this is traditionally the way IBM at least do > things > > > + * > > > + * Whenever the translation fails, the *host pointer will be set > to > > > the > > > + * device that lacks a tranlation, and the return code is relative > to > > > + * that node. > > > > This seems to be wrong to me. We are abusing of the error conditions. > > So effectively if there is a buggy DT for an IO resource we end up > > assuming that we are using a special IO device with unmapped > addresses. > > > > The patch at the bottom apply on top of this one and I think is a > more > > reasonable approach > > It was meant as a logical extension to the existing interface, > translating the address as far as we can, and reporting back > how far we got. > > Maybe we can return 'of_root' by instead of NULL to signify > that we have converted all the way to the root of the DT? > That would make it more consistent, but slightly more complicated > for the common case. Mmm not sure really...the point is that now the **host parameter is used both as a flag and also in of_translate_ioport...the problem that I see is where we set the "host" parameter...I have a proposal below... [...] > pci_bus_alloc_resource(struct > > > pci_bus *bus, > > > void *alignf_data); > > [Many lines of reply trimmed here, please make sure you don't quote too > much context when you reply, it's really annoying to read through > it otherwise] Sorry! I'll take care of this in the future... > > > /* > > + * of_isa_indirect_io - get the IO address from some isa reg > property value. > > + * For some isa/lpc devices, no ranges property in ancestor node. > > + * The device addresses are described directly in their regs > property. > > + * This fixup function will be called to get the IO address of > isa/lpc > > + * devices when the normal of_translation failed. > > + * > > + * @parent: points to the parent dts node; > > + * @bus: points to the of_bus which can be used to parse > address; > > + * @addr: the address from reg property; > > + * @na: the address cell counter of @addr; > > + * @presult: store the address paresed from @addr; > > + * > > + * return 1 when successfully get the I/O address; > > + * 0 will return for some failures. > > + */ > > +static int of_get_isa_indirect_io(struct device_node *parent, > > + struct of_bus *bus, __be32 *addr, > > + int na, u64 *presult) > > +{ > > + unsigned int flags; > > + unsigned int rlen; > > + > > + /* whether support indirectIO */ > > + if (!indirect_io_enabled()) > > + return 0; > > + > > + if (!of_bus_isa_match(parent)) > > + return 0; > > + > > + flags = bus->get_flags(addr); > > + if (!(flags & IORESOURCE_IO)) > > + return 0; > > + > > + /* there is ranges property, apply the normal translation > directly. */ > > + if (of_get_property(parent, "ranges", &rlen)) > > + return 0; > > + > > + *presult = of_read_number(addr + 1, na - 1); > > + /* this fixup is only valid for specific I/O range. */ > > + return addr_is_indirect_io(*presult); > > +} > > Right, this would work. The reason I didn't go down this route is > that I wanted to keep it generic enough to allow doing the same > for PCI host bridges with a nonlinear mapping of the I/O space. > > There isn't really anything special about ISA here, other than the > fact that the one driver that needs it happens to be for ISA rather > than PCI. Yes I see your point please consider the patch at the bottom... > > > +/* > > * Translate an address from the device-tree into a CPU physical > address, > > * this walks up the tree and applies the various bus mappings on > the > > * way. > > @@ -600,14 +643,23 @@ static u64 __of_translate_address(struct > device_node *dev, > > result = of_read_number(addr, na); > > break; > > } > > + /* > > + * For indirectIO device which has no ranges property, get > > + * the address from reg directly. > > + */ > > + if (of_get_isa_indirect_io(dev, bus, addr, na, &result)) { > > + pr_debug("isa indirectIO matched(%s)..addr = > 0x%llx\n", > > + of_node_full_name(dev), result); > > + *host = of_node_get(parent); > > + break; > > + } > > > > If we do the special case for ISA as you suggest above, I would still > want > to keep it in of_translate_ioport(), I think that's a useful change by > itself in my patch. This comes without saying...the patch I proposed here already applied on top of your changes and, in fact, you can see that I set "*host = of_node_get(parent);" above in my patch to be used by of_translate_ioport() > > Arnde > > > Below I have reworked my patch (that still applies on top of your one) to make it not ISA specific. Notice that of_translate_ioport() still stands and that in addr_is_indirect_io() we make sure the bus address to be in the bus address range that the special host operates on... --- drivers/of/address.c | 56 ++++++++++++++++++++++++++++++++++++++++++++-- include/linux/of_address.h | 17 ++++++++++++++ 2 files changed, 71 insertions(+), 2 deletions(-) diff --git a/drivers/of/address.c b/drivers/of/address.c index 5decaba..2b34931 100644 --- a/drivers/of/address.c +++ b/drivers/of/address.c @@ -540,6 +540,48 @@ static u64 of_translate_one(struct device_node *parent, struct of_bus *bus, } /* + * of_get_indirect_io - get the IO address from some reg property value. + * For some special host devices, we have no ranges property node and + * we directly use the bus addresses of the children regs property. + * This fixup function will be called to get the IO address of isa/lpc + * devices when the normal of_translation failed. + * + * @parent: points to the parent dts node; + * @bus: points to the of_bus which can be used to parse address; + * @addr: the address from reg property; + * @na: the address cell counter of @addr; + * @presult: store the address parsed from @addr; + * + * return 1 when successfully get the I/O address; + * 0 will return for some failures. + */ +static int of_get_indirect_io(struct device_node *parent, + struct of_bus *bus, __be32 *addr, + int na, u64 *presult) +{ + unsigned int flags; + unsigned int rlen; + + /* whether support indirectIO */ + if (!indirect_io_enabled()) + return 0; + + flags = bus->get_flags(addr); + if (!(flags & IORESOURCE_IO)) + return 0; + + /* there is ranges property, apply the normal translation directly. */ + if (of_get_property(parent, "ranges", &rlen)) + return 0; + + *presult = of_read_number(addr + 1, na - 1); + + /* check if the bus address falls into the range of + * the special host device*/ + return addr_is_indirect_io(*presult); +} + +/* * Translate an address from the device-tree into a CPU physical address, * this walks up the tree and applies the various bus mappings on the * way. @@ -601,13 +643,23 @@ static u64 __of_translate_address(struct device_node *dev, break; } + /* + * For indirectIO device which has no ranges property, get + * the address from reg directly. + */ + if (of_get_indirect_io(dev, bus, addr, na, &result)) { + pr_debug("isa indirectIO matched(%s)..addr = 0x%llx\n", + of_node_full_name(dev), result); + *host = of_node_get(parent); + break; + } + /* Get new parent bus and counts */ pbus = of_match_bus(parent); pbus->count_cells(dev, &pna, &pns); if (!OF_CHECK_COUNTS(pna, pns)) { - pr_debug("Bad cell count for %s\n", + pr_err("Bad cell count for %s\n", of_node_full_name(dev)); - *host = of_node_get(parent); break; } diff --git a/include/linux/of_address.h b/include/linux/of_address.h index 3786473..14848d8 100644 --- a/include/linux/of_address.h +++ b/include/linux/of_address.h @@ -24,6 +24,23 @@ struct of_pci_range { #define for_each_of_pci_range(parser, range) \ for (; of_pci_range_parser_one(parser, range);) +#ifndef indirect_io_enabled +#define indirect_io_enabled indirect_io_enabled +static inline bool indirect_io_enabled(void) +{ + return false; +} +#endif + +#ifndef addr_is_indirect_io +#define addr_is_indirect_io addr_is_indirect_io +static inline int addr_is_indirect_io(u64 taddr) +{ + return 0; +} +#endif + + /* Translate a DMA address from device space to CPU space */ extern u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr); -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
