From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753488AbaIHOwc (ORCPT ); Mon, 8 Sep 2014 10:52:32 -0400 Received: from mail-wg0-f45.google.com ([74.125.82.45]:36067 "EHLO mail-wg0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751891AbaIHOwa (ORCPT ); Mon, 8 Sep 2014 10:52:30 -0400 From: Grant Likely Subject: Re: [PATCH] RFC: add function for localbus address To: Stanimir Varbanov Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, Rob Herring , Rob Herring , Arnd Bergmann , Lee Jones , Stephen Boyd , Stanimir Varbanov In-Reply-To: <1409672700-21697-1-git-send-email-svarbanov@mm-sol.com> References: <20140729234522.E9FF1C40738@trevor.secretlab.ca> <1409672700-21697-1-git-send-email-svarbanov@mm-sol.com> Date: Mon, 08 Sep 2014 15:52:04 +0100 Message-Id: <20140908145204.8ADC2C40AE5@trevor.secretlab.ca> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2 Sep 2014 18:45:00 +0300, Stanimir Varbanov wrote: > Hi Grant, > > I came down to this. Could you review? Is that > implementation closer to the suggestion made by you. > > --- > drivers/of/address.c | 49 ++++++++++++++++++++++++++++++++++++++++++++ > drivers/of/platform.c | 20 ++++++++++++++--- > include/linux/of_address.h | 19 +++++++++++++++++ > 3 files changed, 84 insertions(+), 4 deletions(-) > > diff --git a/drivers/of/address.c b/drivers/of/address.c > index e371825..86c2166 100644 > --- a/drivers/of/address.c > +++ b/drivers/of/address.c > @@ -601,6 +601,32 @@ const __be32 *of_get_address(struct device_node *dev, int index, u64 *size, > } > EXPORT_SYMBOL(of_get_address); > > +const __be32 *of_get_localbus_address(struct device_node *np, int index, > + u64 *size) > +{ > + struct device_node *root, *parent; > + const __be32 *ranges, *prop = NULL; > + > + parent = of_get_parent(np); > + if (!parent) > + return NULL; > + > + root = of_find_node_by_path("/"); > + > + if (parent == root) { > + of_node_put(parent); > + return NULL; > + } > + > + ranges = of_get_property(parent, "ranges", NULL); > + of_node_put(parent); > + > + if (!ranges) > + prop = of_get_address(np, index, size, NULL); > + > + return prop; > +} So, the above doesn't make much sense to me. It looks like the function merely decodes the local address, and the below function will stuff it into a resource structure, but the tests for if the parent is root or the parent has a ranges property are nonsensical. That shouldn't matter for the functionality (except for automatically decoding them.. more below) > + > unsigned long __weak pci_address_to_pio(phys_addr_t address) > { > if (address > IO_SPACE_LIMIT) > @@ -665,6 +691,29 @@ int of_address_to_resource(struct device_node *dev, int index, > } > EXPORT_SYMBOL_GPL(of_address_to_resource); > > +int of_localbus_address_to_resource(struct device_node *dev, int index, > + struct resource *r) > +{ > + const char *name = NULL; > + const __be32 *addrp; > + u64 size; > + > + addrp = of_get_localbus_address(dev, index, &size); > + if (!addrp) > + return -EINVAL; > + > + of_property_read_string_index(dev, "reg-names", index, &name); > + > + memset(r, 0, sizeof(*r)); > + r->start = be32_to_cpup(addrp); > + r->end = r->start + size - 1; > + r->flags = IORESOURCE_REG; This is problematic. A resource is created, but there is absolutely no indication that the resource represents a localbus address instead of a CPU address. platform_device reg resources represent CPU addresses. Trying to overload it will cause confusion in drivers. > + r->name = name ? name : dev->full_name; > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(of_localbus_address_to_resource); > + > struct device_node *of_find_matching_node_by_address(struct device_node *from, > const struct of_device_id *matches, > u64 base_address) > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > index 0197725..36dcbd7 100644 > --- a/drivers/of/platform.c > +++ b/drivers/of/platform.c > @@ -106,8 +106,9 @@ struct platform_device *of_device_alloc(struct device_node *np, > struct device *parent) > { > struct platform_device *dev; > - int rc, i, num_reg = 0, num_irq; > + int rc, i, num_reg = 0, num_localbus_reg = 0, num_irq; > struct resource *res, temp_res; > + int num_resources; > > dev = platform_device_alloc("", -1); > if (!dev) > @@ -116,22 +117,33 @@ struct platform_device *of_device_alloc(struct device_node *np, > /* count the io and irq resources */ > while (of_address_to_resource(np, num_reg, &temp_res) == 0) > num_reg++; > + > + while (of_localbus_address_to_resource(np, > + num_localbus_reg, &temp_res) == 0) > + num_localbus_reg++; > + No, I don't support doing this. The moment a platform_driver depends on a local bus address it is doing something special. It needs to decode its own address in that case, which it can easily do. Any platform_driver that interprets a IORESOURCE_REG as a localbus address instead of a CPU address is *BROKEN*. It should be changed to either decode the address itself, of a new bus type should be created that can make its own decisions about what address resources mean. I realize that you want to reuse the platform populate functionality in this case. We can refactor some of that code to make it usable for customized platform_bus_type instances. g.