From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755000Ab3ADAIH (ORCPT ); Thu, 3 Jan 2013 19:08:07 -0500 Received: from mail4.aviatnet.com ([192.147.115.31]:56656 "EHLO mail4.aviatnet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754870Ab3ADAHl (ORCPT ); Thu, 3 Jan 2013 19:07:41 -0500 X-Greylist: delayed 309 seconds by postgrey-1.27 at vger.kernel.org; Thu, 03 Jan 2013 19:07:41 EST Message-ID: <1357257748.31023.12.camel@pc786-ubu.GNET.GLOBAL.VPN> Subject: [PATCH] mtd: m25p80: Flash protection support for STmicro chips From: Austin Boyle To: David Woodhouse , CC: , Artem Bityutskiy Date: Fri, 4 Jan 2013 13:02:28 +1300 Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-Originating-IP: [10.16.1.76] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch adds generic support for flash protection on STmicro chips. On chips with less than 3 protection bits, the unused bits are don't cares and so can be written anyway. The lock function will only change the protection bits if it would not unlock other areas. Similarly, the unlock function will not lock currently unlocked areas. Tested on the m25p64. From: Austin Boyle Signed-off-by: Austin Boyle --- diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c index 4eeeb2d..069e34f 100644 --- a/drivers/mtd/devices/m25p80.c +++ b/drivers/mtd/devices/m25p80.c @@ -565,6 +565,96 @@ time_out: return ret; } +static int m25p80_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len) +{ + struct m25p *flash = mtd_to_m25p(mtd); + uint32_t offset = ofs; + uint8_t status_old, status_new; + int res = 0; + + mutex_lock(&flash->lock); + /* Wait until finished previous command */ + if (wait_till_ready(flash)) { + res = 1; + goto err; + } + + status_old = read_sr(flash); + + if (offset < flash->mtd.size-(flash->mtd.size/2)) + status_new = status_old | SR_BP2 | SR_BP1 | SR_BP0; + else if (offset < flash->mtd.size-(flash->mtd.size/4)) + status_new = (status_old & ~SR_BP0) | SR_BP2 | SR_BP1; + else if (offset < flash->mtd.size-(flash->mtd.size/8)) + status_new = (status_old & ~SR_BP1) | SR_BP2 | SR_BP0; + else if (offset < flash->mtd.size-(flash->mtd.size/16)) + status_new = (status_old & ~(SR_BP0|SR_BP1)) | SR_BP2; + else if (offset < flash->mtd.size-(flash->mtd.size/32)) + status_new = (status_old & ~SR_BP2) | SR_BP1 | SR_BP0; + else if (offset < flash->mtd.size-(flash->mtd.size/64)) + status_new = (status_old & ~(SR_BP2|SR_BP0)) | SR_BP1; + else + status_new = (status_old & ~(SR_BP2|SR_BP1)) | SR_BP0; + + /* Only modify protection if it will not unlock other areas */ + if ((status_new&(SR_BP2|SR_BP1|SR_BP0)) > + (status_old&(SR_BP2|SR_BP1|SR_BP0))) { + write_enable(flash); + if (write_sr(flash, status_new) < 0) { + res = 1; + goto err; + } + } + +err: mutex_unlock(&flash->lock); + return res; +} + +static int m25p80_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len) +{ + struct m25p *flash = mtd_to_m25p(mtd); + uint32_t offset = ofs; + uint8_t status_old, status_new; + int res = 0; + + mutex_lock(&flash->lock); + /* Wait until finished previous command */ + if (wait_till_ready(flash)) { + res = 1; + goto err; + } + + status_old = read_sr(flash); + + if (offset+len > flash->mtd.size-(flash->mtd.size/64)) + status_new = status_old & ~(SR_BP2|SR_BP1|SR_BP0); + else if (offset+len > flash->mtd.size-(flash->mtd.size/32)) + status_new = (status_old & ~(SR_BP2|SR_BP1)) | SR_BP0; + else if (offset+len > flash->mtd.size-(flash->mtd.size/16)) + status_new = (status_old & ~(SR_BP2|SR_BP0)) | SR_BP1; + else if (offset+len > flash->mtd.size-(flash->mtd.size/8)) + status_new = (status_old & ~SR_BP2) | SR_BP1 | SR_BP0; + else if (offset+len > flash->mtd.size-(flash->mtd.size/4)) + status_new = (status_old & ~(SR_BP0|SR_BP1)) | SR_BP2; + else if (offset+len > flash->mtd.size-(flash->mtd.size/2)) + status_new = (status_old & ~SR_BP1) | SR_BP2 | SR_BP0; + else + status_new = (status_old & ~SR_BP0) | SR_BP2 | SR_BP1; + + /* Only modify protection if it will not lock other areas */ + if ((status_new&(SR_BP2|SR_BP1|SR_BP0)) < + (status_old&(SR_BP2|SR_BP1|SR_BP0))) { + write_enable(flash); + if (write_sr(flash, status_new) < 0) { + res = 1; + goto err; + } + } + +err: mutex_unlock(&flash->lock); + return res; +} + /****************************************************************************/ /* @@ -899,6 +989,12 @@ static int m25p_probe(struct spi_device *spi) flash->mtd._erase = m25p80_erase; flash->mtd._read = m25p80_read; + /* flash protection support for STmicro chips */ + if (JEDEC_MFR(info->jedec_id) == CFI_MFR_ST) { + flash->mtd._lock = m25p80_lock; + flash->mtd._unlock = m25p80_unlock; + } + /* sst flash chips use AAI word program */ if (JEDEC_MFR(info->jedec_id) == CFI_MFR_SST) flash->mtd._write = sst_write;