From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2FC8BC433F5 for ; Tue, 24 May 2022 21:31:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241911AbiEXVbL (ORCPT ); Tue, 24 May 2022 17:31:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33312 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230110AbiEXVbI (ORCPT ); Tue, 24 May 2022 17:31:08 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 22B39C26 for ; Tue, 24 May 2022 14:31:06 -0700 (PDT) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 24OLLr1t010538; Tue, 24 May 2022 21:30:57 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding; s=pp1; bh=qKIrqNLPjaLRBqiv4WGWBu1SfM8aEazEXMVCpIalUaA=; b=QJCk2vz8emPFw9K1NUEdxUUuEeKx8N2W8LHmtcmcimoor3ng/E2LJmy0dBDoLN+g9Ene 14k5Jt4sLBkKoQ6EG5x5//Jk3dfYI1TWPnd+tWsGQ/P7hiZ3trBmWTlRTPnEoZ2Qi7VK arWYp1CdPtDw1Z2b6k2l5pKghx+MxXz5nOEBvwZluE2UuNAbn2LfFdiktci7yiOrmQk5 u6NDqgztveHK99QFLK3I1MjMCIFljcPHgkQPXjoEavQp1WbkfKKz10LpLYd5I5OQKylg L1PbjojZ+nCwX2NCRglH0p90wm6A61Puq0CRSu8NrOOZ992kXejGWodQ21wfmoYM+zP/ hg== Received: from ppma03dal.us.ibm.com (b.bd.3ea9.ip4.static.sl-reverse.com [169.62.189.11]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3g977ar3jh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 24 May 2022 21:30:57 +0000 Received: from pps.filterd (ppma03dal.us.ibm.com [127.0.0.1]) by ppma03dal.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 24OLS1hE026369; Tue, 24 May 2022 21:30:56 GMT Received: from b01cxnp22035.gho.pok.ibm.com (b01cxnp22035.gho.pok.ibm.com [9.57.198.25]) by ppma03dal.us.ibm.com with ESMTP id 3g93ut9qve-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 24 May 2022 21:30:56 +0000 Received: from b01ledav005.gho.pok.ibm.com (b01ledav005.gho.pok.ibm.com [9.57.199.110]) by b01cxnp22035.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 24OLUtLq21037386 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 24 May 2022 21:30:55 GMT Received: from b01ledav005.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AB41AAE062; Tue, 24 May 2022 21:30:55 +0000 (GMT) Received: from b01ledav005.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 12F58AE05C; Tue, 24 May 2022 21:30:55 +0000 (GMT) Received: from v0005c16.aus.stglabs.ibm.com (unknown [9.211.82.60]) by b01ledav005.gho.pok.ibm.com (Postfix) with ESMTP; Tue, 24 May 2022 21:30:54 +0000 (GMT) From: Eddie James To: linux-kernel@vger.kernel.org Cc: arnd@arndb.de, gregkh@linuxfoundation.org, Brad Bishop , Eddie James , Joel Stanley Subject: [PATCH] eeprom: at25: Split reads into chunks and cap write size Date: Tue, 24 May 2022 16:30:43 -0500 Message-Id: <20220524213043.57559-1-eajames@linux.ibm.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 0eDLgV76QWcYSiEpyNuDq0HGIxrqz_1T X-Proofpoint-GUID: 0eDLgV76QWcYSiEpyNuDq0HGIxrqz_1T X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.874,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-24_10,2022-05-23_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 mlxlogscore=999 mlxscore=0 lowpriorityscore=0 phishscore=0 clxscore=1011 impostorscore=0 suspectscore=0 priorityscore=1501 malwarescore=0 adultscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2204290000 definitions=main-2205240105 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Brad Bishop Make use of spi_max_transfer_size to avoid requesting transfers that are too large for some spi controllers. Signed-off-by: Brad Bishop Signed-off-by: Eddie James Signed-off-by: Joel Stanley --- drivers/misc/eeprom/at25.c | 93 ++++++++++++++++++++++---------------- 1 file changed, 53 insertions(+), 40 deletions(-) diff --git a/drivers/misc/eeprom/at25.c b/drivers/misc/eeprom/at25.c index 8d169a35cf13..0434ffa6ec4c 100644 --- a/drivers/misc/eeprom/at25.c +++ b/drivers/misc/eeprom/at25.c @@ -79,6 +79,11 @@ static int at25_ee_read(void *priv, unsigned int offset, { struct at25_data *at25 = priv; char *buf = val; + size_t max_chunk = spi_max_transfer_size(at25->spi); + size_t num_msgs = DIV_ROUND_UP(count, max_chunk); + size_t nr_bytes = 0; + unsigned int msg_offset; + size_t msg_count; u8 *cp; ssize_t status; struct spi_transfer t[2]; @@ -92,54 +97,59 @@ static int at25_ee_read(void *priv, unsigned int offset, if (unlikely(!count)) return -EINVAL; - cp = at25->command; + msg_offset = (unsigned int)offset; + msg_count = min(count, max_chunk); + while (num_msgs) { + cp = at25->command; - instr = AT25_READ; - if (at25->chip.flags & EE_INSTR_BIT3_IS_ADDR) - if (offset >= BIT(at25->addrlen * 8)) - instr |= AT25_INSTR_BIT3; + instr = AT25_READ; + if (at25->chip.flags & EE_INSTR_BIT3_IS_ADDR) + if (msg_offset >= (1U << (at25->addrlen * 8))) + instr |= AT25_INSTR_BIT3; - mutex_lock(&at25->lock); + mutex_lock(&at25->lock); - *cp++ = instr; - - /* 8/16/24-bit address is written MSB first */ - switch (at25->addrlen) { - default: /* case 3 */ - *cp++ = offset >> 16; - fallthrough; - case 2: - *cp++ = offset >> 8; - fallthrough; - case 1: - case 0: /* can't happen: for better code generation */ - *cp++ = offset >> 0; - } + *cp++ = instr; - spi_message_init(&m); - memset(t, 0, sizeof(t)); + /* 8/16/24-bit address is written MSB first */ + switch (at25->addrlen) { + default: /* case 3 */ + *cp++ = msg_offset >> 16; + fallthrough; + case 2: + *cp++ = msg_offset >> 8; + fallthrough; + case 1: + case 0: /* can't happen: for better codegen */ + *cp++ = msg_offset >> 0; + } - t[0].tx_buf = at25->command; - t[0].len = at25->addrlen + 1; - spi_message_add_tail(&t[0], &m); + spi_message_init(&m); + memset(t, 0, sizeof(t)); - t[1].rx_buf = buf; - t[1].len = count; - spi_message_add_tail(&t[1], &m); + t[0].tx_buf = at25->command; + t[0].len = at25->addrlen + 1; + spi_message_add_tail(&t[0], &m); - /* - * Read it all at once. - * - * REVISIT that's potentially a problem with large chips, if - * other devices on the bus need to be accessed regularly or - * this chip is clocked very slowly. - */ - status = spi_sync(at25->spi, &m); - dev_dbg(&at25->spi->dev, "read %zu bytes at %d --> %zd\n", - count, offset, status); + t[1].rx_buf = buf + nr_bytes; + t[1].len = msg_count; + spi_message_add_tail(&t[1], &m); - mutex_unlock(&at25->lock); - return status; + status = spi_sync(at25->spi, &m); + + mutex_unlock(&at25->lock); + + if (status) + return status; + + --num_msgs; + msg_offset += msg_count; + nr_bytes += msg_count; + } + + dev_dbg(&at25->spi->dev, "read %zu bytes at %d\n", + count, offset); + return 0; } /* Read extra registers as ID or serial number */ @@ -190,6 +200,7 @@ ATTRIBUTE_GROUPS(sernum); static int at25_ee_write(void *priv, unsigned int off, void *val, size_t count) { struct at25_data *at25 = priv; + size_t maxsz = spi_max_transfer_size(at25->spi); const char *buf = val; int status = 0; unsigned buf_size; @@ -253,6 +264,8 @@ static int at25_ee_write(void *priv, unsigned int off, void *val, size_t count) segment = buf_size - (offset % buf_size); if (segment > count) segment = count; + if (segment > maxsz) + segment = maxsz; memcpy(cp, buf, segment); status = spi_write(at25->spi, bounce, segment + at25->addrlen + 1); -- 2.27.0