From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757338Ab0IXSXc (ORCPT ); Fri, 24 Sep 2010 14:23:32 -0400 Received: from e2.ny.us.ibm.com ([32.97.182.142]:40747 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932538Ab0IXSXa (ORCPT ); Fri, 24 Sep 2010 14:23:30 -0400 Date: Fri, 24 Sep 2010 11:23:27 -0700 From: Vernon Mauery To: Arnd Bergmann Cc: Randy Dunlap , Linux Kernel Mailing List , Keith Mannthey Subject: Re: [RFC][Patch] IBM Real-Time "SMI Free" mode driver -v4 Message-ID: <20100924182327.GC10777@lucy> References: <20100921224610.GO13162@lucy> <20100924170943.GB10777@lucy> <201009241940.18931.arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <201009241940.18931.arnd@arndb.de> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24-Sep-2010 07:40 PM, Arnd Bergmann wrote: >On Friday 24 September 2010 19:09:43 Vernon Mauery wrote: >> I looked into this and tested it on some hardware, but it doesn't work. >> After more digging and poking, it looks like the reason is that the port >> IO address is not within the x86 standard port IO range. >> >> I tried something like this: >> >> addr = ioread32(&rtl_table->cmd_port_address); >> plen = rtl_cmd_width/8; >> if (rtl_cmd_type == RTL_ADDR_TYPE_MMIO) >> rtl_cmd_addr = ioremap(addr, plen); >> else >> rtl_cmd_addr = ioport_map(addr, plen); >> RTL_DEBUG("rtl_cmd_addr = %#llx\n", (u64)rtl_cmd_addr); >> >> It printed out that rtl_cmd_addr was 0, meaning the ioport_map failed. >> After more digging, it turns out that on at least one of the machines >> this code is targeted for, the port IO address (from the first line >> above) is 0x40000. Even if this did get mapped, the IO_COND macro would >> target it for MMIO access instead of PIO access. So I don't think I can >> use this method (even though it did make my code a lot nicer to read). >> >> Any suggestions? > >That seems really strange. I thought the inb/outb instructions could not >actually operate on addresses above 0x10000 at all, since they take a 16 >bit address operand (DX register). Passing 0x40000 into inb should have the >same effect as zero AFAICT, which means that your existing code should not >work either. No, inb/outb have address as as unsigned long, which would explain why 0x40000 works with PIO. When doing inb/outb via the ioread/iowrite macros, the port value is the address (minus the offset) masked off to PIO_MASK, which is 16 bits on x86. So it looks like this really not going to work and I will have to go back to how it was before. Would it be tacky to write my own little macro? >For non-x86 architectures, I would recommend defining HAVE_ARCH_PIO_SIZE >and setting PIO_RESERVED to a higher value. Unfortunately, this is targeted only for x86 platforms. --Vernon