From 972e1b7b450a93589b2a4c709e68f68da059aa5c Mon Sep 17 00:00:00 2001 From: Austin Boyle Date: Fri, 4 Jan 2013 13:02:28 +1300 Subject: [PATCH] mtd: m25p80: Flash protection support for STmicro chips 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. Signed-off-by: Austin Boyle Signed-off-by: Artem Bityutskiy --- drivers/mtd/devices/m25p80.c | 96 ++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c index 4eeeb2d7f6ea..069e34f909ed 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; -- 2.34.1