Return-path: Received: from mail-qw0-f46.google.com ([209.85.216.46]:37037 "EHLO mail-qw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932296Ab1DMUiF convert rfc822-to-8bit (ORCPT ); Wed, 13 Apr 2011 16:38:05 -0400 MIME-Version: 1.0 In-Reply-To: References: <1302634375-2378-1-git-send-email-zajec5@gmail.com> <20110413163113.GA24015@kroah.com> From: =?ISO-8859-1?Q?G=E1bor_Stefanik?= Date: Wed, 13 Apr 2011 22:37:44 +0200 Message-ID: Subject: Re: [RFC][PATCH V4] axi: add AXI bus driver To: =?ISO-8859-2?Q?Rafa=B3_Mi=B3ecki?= Cc: Greg KH , linux-wireless@vger.kernel.org, "John W. Linville" , b43-dev@lists.infradead.org, =?ISO-8859-1?Q?Michael_B=FCsch?= , Larry Finger , George Kashperko , Arend van Spriel , linux-arm-kernel@lists.infradead.org, Russell King , Arnd Bergmann , Andy Botting , linuxdriverproject , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, Apr 13, 2011 at 9:39 PM, Rafał Miłecki wrote: > 2011/4/13 Greg KH : >>> diff --git a/drivers/axi/axi_pci_bridge.c b/drivers/axi/axi_pci_bridge.c >>> new file mode 100644 >>> index 0000000..17e882c >>> --- /dev/null >>> +++ b/drivers/axi/axi_pci_bridge.c >>> @@ -0,0 +1,33 @@ >>> +/* >>> + * AXI PCI bridge module >>> + * >>> + * Licensed under the GNU/GPL. See COPYING for details. >>> + */ >>> + >>> +#include "axi_private.h" >>> + >>> +#include >>> +#include >>> + >>> +static DEFINE_PCI_DEVICE_TABLE(axi_pci_bridge_tbl) = { >>> +     { PCI_DEVICE(PCI_VENDOR_ID_BROADCOM, 0x4331) }, >>> +     { PCI_DEVICE(PCI_VENDOR_ID_BROADCOM, 0x4353) }, >>> +     { PCI_DEVICE(PCI_VENDOR_ID_BROADCOM, 0x4727) }, >>> +     { 0, }, >>> +}; >>> +MODULE_DEVICE_TABLE(pci, axi_pci_bridge_tbl); >>> + >>> +static struct pci_driver axi_pci_bridge_driver = { >>> +     .name = "axi-pci-bridge", >>> +     .id_table = axi_pci_bridge_tbl, >>> +}; >>> + >>> +int __init axi_pci_bridge_init(void) >>> +{ >>> +     return axi_host_pci_register(&axi_pci_bridge_driver); >>> +} >>> + >>> +void __exit axi_pci_bridge_exit(void) >>> +{ >>> +     axi_host_pci_unregister(&axi_pci_bridge_driver); >>> +} >> >> You register a pci driver that does nothing?  That's not right, you need >> to then base your axi bus off of that pci device, so it is hooked up >> correctly in the /sys/devices/ tree.  Otherwise you are somewhere up in >> the virtual location for your axi bus, right? > > Please take a look at: > driver->probe = axi_host_pci_probe; > driver->remove = axi_host_pci_remove; > return pci_register_driver(driver); > > >>> +bool axi_core_is_enabled(struct axi_device *core) >>> +{ >>> +     if ((axi_aread32(core, AXI_IOCTL) & (AXI_IOCTL_CLK | AXI_IOCTL_FGC)) >>> +         != AXI_IOCTL_CLK) >>> +             return false; >>> +     if (axi_aread32(core, AXI_RESET_CTL) & AXI_RESET_CTL_RESET) >>> +             return false; >>> +     return true; >>> +} >>> +EXPORT_SYMBOL(axi_core_is_enabled); >> >> EXPORT_SYMBOL_GPL()? >> >> What module uses this?  And why would it care? >> >>> +EXPORT_SYMBOL(axi_core_enable); >> >> EXPORT_SYMBOL_GPL()? >> >> Same goes for your other exports, just want you to be sure here. > > Hm, I'm not sure. Using EXPORT_SYMBOL_GPL will forbid closed source > drivers from using our bus driver, right? I'm don't have preferences > on this, if you prefer us to force GPL, I can. Isn't EXPORT_SYMBOL_GPL for symbols that are considered to form a tight coupling between the kernel and users of the symbol? Using _GPL just because you are against proprietary drivers in general and want to force GPL on HW vendors is wrong. > > >>> +u32 xaxi_chipco_gpio_control(struct axi_drv_cc *cc, u32 mask, u32 value) >>> +{ >>> +     return axi_cc_write32_masked(cc, AXI_CC_GPIOCTL, mask, value); >>> +} >>> +EXPORT_SYMBOL(xaxi_chipco_gpio_control); >> >> "xaxi"?  Shouldn't that be consistant with the other exports and start >> with "axi"? > > Left from old tests/rewrites/splitting. Thanks. > > >>> +static u8 axi_host_pci_read8(struct axi_device *core, u16 offset) >>> +{ >>> +     if (unlikely(core->bus->mapped_core != core)) >> >> Are you sure about the use of unlikely in this, and other functions? >> The compiler almost always does a better job than we do for these types >> of calls, just let it do it's job. >> >>> +             axi_host_pci_switch_core(core); >>> +     return ioread8(core->bus->mmio + offset); >> >> I think because of that unlikely, you just slowed down all pci devices, >> right?  That's not very nice :) > > Hm, my logic suggests it is alright, but please consider this once > more with me ;) > > For the most of the time mapped_core (active core) do not change. We > perform few hundreds of operations on one core in a row. This way > mapped_core points to passed core for most of the time. Condition > (mapped_core != core) is unlikely to happen. > > Is there anything wrong in my logic? > > -- > Rafał > -- > To unsubscribe from this list: send the line "unsubscribe linux-wireless" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  http://vger.kernel.org/majordomo-info.html > -- Vista: [V]iruses, [I]ntruders, [S]pyware, [T]rojans and [A]dware. :-)