Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754565Ab2HaQtO (ORCPT ); Fri, 31 Aug 2012 12:49:14 -0400 Received: from wolverine02.qualcomm.com ([199.106.114.251]:13838 "EHLO wolverine02.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754040Ab2HaQtN (ORCPT ); Fri, 31 Aug 2012 12:49:13 -0400 X-IronPort-AV: E=McAfee;i="5400,1158,6820"; a="229425086" Message-ID: <5040EAF7.9010003@codeaurora.org> Date: Fri, 31 Aug 2012 09:48:55 -0700 From: Stephen Boyd User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:14.0) Gecko/20120713 Thunderbird/14.0 MIME-Version: 1.0 To: Matthieu CASTET CC: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, gregkh@linuxfoundation.org, arnd@arndb.de, alan@lxorguk.ukuu.org.uk, Matthieu Castet Subject: Re: [PATCH v2] hvc_dcc : add support to armv4 and armv5 core References: <1346413645-4593-1-git-send-email-castet.matthieu@free.fr> In-Reply-To: <1346413645-4593-1-git-send-email-castet.matthieu@free.fr> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2912 Lines: 112 On 8/31/2012 4:47 AM, Matthieu CASTET wrote: > Signed-off-by: Matthieu Castet Please consider adding some sort of commit text. Does this add some new feature I may want on some downstream distro kernel? > @@ -51,7 +51,7 @@ static inline char __dcc_getchar(void) > return __c; > } > > -static inline void __dcc_putchar(char c) > +static inline void __dcc_putchar_v6(char c) > { > asm volatile("mcr p14, 0, %0, c0, c5, 0 @ write a char" > : /* no output register */ > @@ -59,6 +59,69 @@ static inline void __dcc_putchar(char c) > isb(); > } > > +static int hvc_dcc_put_chars_v6(uint32_t vt, const char *buf, int count) > +{ > + int i; > + > + for (i = 0; i < count; i++) { > + while (__dcc_getstatus_v6() & DCC_STATUS_TX_V6) > + cpu_relax(); > + > + __dcc_putchar_v6(buf[i]); > + } > + > + return count; > +} It's unfortunate that the main logic is duplicated. I wonder if we could push the runtime decision slightly lower into the accessor functions instead and make some new functions dcc_tx_busy() and dcc_rx_busy() or something. Then these loops stay the same. > + > +static int hvc_dcc_get_chars_v6(uint32_t vt, char *buf, int count) > +{ > + int i; > + > + for (i = 0; i < count; ++i) > + if (__dcc_getstatus_v6() & DCC_STATUS_RX_V6) > + buf[i] = __dcc_getchar_v6(); > + else > + break; > + > + return i; > +} > + > +static const struct hv_ops hvc_dcc_get_put_ops_v6 = { > + .get_chars = hvc_dcc_get_chars_v6, > + .put_chars = hvc_dcc_put_chars_v6, > +}; > + > +#define DCC_STATUS_RX (1 << 0) > +#define DCC_STATUS_TX (1 << 1) > + > +/* primitive JTAG1 protocol utilities */ This comment doesn't tell me much. Remove it? > +static inline u32 __dcc_getstatus(void) > +{ > + u32 ret; > + > + asm __volatile__ ("mrc p14, 0, %0, c0, c0 @ read comms ctrl reg" > + : "=r" (ret)); Can you use volatile instead of __volatile__ so that the file is consistent? > + > + return ret; > +} > + > +static inline char __dcc_getchar(void) > +{ > + char c; > + > + asm __volatile__ ("mrc p14, 0, %0, c1, c0 @ read comms data reg" > + : "=r" (c)); > + Do you see any multiple character inputs? I think you may need an isb here similar to the v6/7 code and in the putchar as well. > + return c; > +} > + > +static inline void __dcc_putchar(unsigned char c) > +{ > + asm __volatile__ ("mcr p14, 0, %0, c1, c0 @ write a char" > + : /* no output register */ > + : "r" (c)); > +} > + > static int hvc_dcc_put_chars(uint32_t vt, const char *buf, int count) > { > int i; > -- Sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/