Author: stefanct Date: Sat Dec 29 16:04:05 2012 New Revision: 1635 URL: http://flashrom.org/trac/flashrom/changeset/1635
Log: Add a generic SPI block unprotect function.
This does not only remove a huge pile of duplicate code, it does also fix a bug in spi_disable_blockprotect_at25df(), which is also a good example why duplicated code is a bad idea.
Signed-off-by: Stefan Tauner stefan.tauner@student.tuwien.ac.at Acked-by: Stefan Tauner stefan.tauner@student.tuwien.ac.at
Modified: trunk/spi25_statusreg.c
Modified: trunk/spi25_statusreg.c ============================================================================== --- trunk/spi25_statusreg.c Sat Dec 29 16:03:51 2012 (r1634) +++ trunk/spi25_statusreg.c Sat Dec 29 16:04:05 2012 (r1635) @@ -123,35 +123,61 @@ return readarr[0]; }
-/* A generic brute-force block protection disable works like this: - * Write 0x00 to the status register. Check if any locks are still set (that - * part is chip specific). Repeat once. +/* A generic block protection disable. + * Tests if a protection is enabled with the block protection mask (bp_mask) and returns success otherwise. + * Tests if the register bits are locked with the lock_mask (lock_mask). + * Tests if a hardware protection is active (i.e. low) with the write protection mask (wp_mask) and bails out + * in that case. + * Finally tries to disable engaged protections and checks if any locks are still set. */ -int spi_disable_blockprotect(struct flashctx *flash) +static int spi_disable_blockprotect_generic(struct flashctx *flash, uint8_t bp_mask, uint8_t lock_mask, uint8_t wp_mask) { uint8_t status; int result;
status = spi_read_status_register(flash); - /* If block protection is disabled, stop here. */ - if ((status & 0x3c) == 0) + if ((status & bp_mask) == 0) { + msg_cdbg2("Block protection is disabled.\n"); return 0; + }
msg_cdbg("Some block protection in effect, disabling... "); - result = spi_write_status_register(flash, status & ~0x3c); + if ((status & lock_mask) != 0) { + msg_cdbg("\n\tNeed to disable the register lock first... "); + if (wp_mask != 0 && (status & wp_mask) == 0) { + msg_cerr("Hardware protection is active, disabling write protection is impossible.\n"); + return 1; + } + /* All bits except the register lock bit (often called SPRL, SRWD, WPEN) are readonly. */ + result = spi_write_status_register(flash, status & ~lock_mask); + if (result) { + msg_cerr("spi_write_status_register failed.\n"); + return result; + } + msg_cdbg("done.\n"); + } + /* Global unprotect. Make sure to mask the register lock bit as well. */ + result = spi_write_status_register(flash, status & ~(bp_mask | lock_mask)); if (result) { msg_cerr("spi_write_status_register failed.\n"); return result; } status = spi_read_status_register(flash); - if ((status & 0x3c) != 0) { + if ((status & bp_mask) != 0) { msg_cerr("Block protection could not be disabled!\n"); return 1; } - msg_cdbg("done.\n"); + msg_cdbg("disabled.\n"); return 0; }
+/* A common block protection disable that tries to unset the status register bits masked by 0x3C. */ +int spi_disable_blockprotect(struct flashctx *flash) +{ + return spi_disable_blockprotect_generic(flash, 0x3C, 0, 0); +} + + static void spi_prettyprint_status_register_hex(uint8_t status) { msg_cdbg("Chip status register is 0x%02x.\n", status); @@ -414,43 +440,7 @@
int spi_disable_blockprotect_at25df(struct flashctx *flash) { - uint8_t status; - int result; - - status = spi_read_status_register(flash); - /* If block protection is disabled, stop here. */ - if ((status & (3 << 2)) == 0) - return 0; - - msg_cdbg("Some block protection in effect, disabling... "); - if (status & (1 << 7)) { - msg_cdbg("Need to disable Sector Protection Register Lock\n"); - if ((status & (1 << 4)) == 0) { - msg_cerr("WP# pin is active, disabling " - "write protection is impossible.\n"); - return 1; - } - /* All bits except bit 7 (SPRL) are readonly. */ - result = spi_write_status_register(flash, status & ~(1 << 7)); - if (result) { - msg_cerr("spi_write_status_register failed.\n"); - return result; - } - - } - /* Global unprotect. Make sure to mask SPRL as well. */ - result = spi_write_status_register(flash, status & ~0xbc); - if (result) { - msg_cerr("spi_write_status_register failed.\n"); - return result; - } - status = spi_read_status_register(flash); - if ((status & (3 << 2)) != 0) { - msg_cerr("Block protection could not be disabled!\n"); - return 1; - } - msg_cdbg("done.\n"); - return 0; + return spi_disable_blockprotect_generic(flash, 0x0C, 1 << 7, 1 << 4); }
int spi_disable_blockprotect_at25df_sec(struct flashctx *flash) @@ -470,72 +460,12 @@
int spi_disable_blockprotect_at25fs010(struct flashctx *flash) { - uint8_t status; - int result; - - status = spi_read_status_register(flash); - /* If block protection is disabled, stop here. */ - if ((status & 0x6c) == 0) - return 0; - - msg_cdbg("Some block protection in effect, disabling... "); - if (status & (1 << 7)) { - msg_cdbg("Need to disable Status Register Write Protect\n"); - /* Clear bit 7 (WPEN). */ - result = spi_write_status_register(flash, status & ~(1 << 7)); - if (result) { - msg_cerr("spi_write_status_register failed.\n"); - return result; - } - } - /* Global unprotect. Make sure to mask WPEN as well. */ - result = spi_write_status_register(flash, status & ~0xec); - if (result) { - msg_cerr("spi_write_status_register failed.\n"); - return result; - } - status = spi_read_status_register(flash); - if ((status & 0x6c) != 0) { - msg_cerr("Block protection could not be disabled!\n"); - return 1; - } - msg_cdbg("done.\n"); - return 0; -} + return spi_disable_blockprotect_generic(flash, 0x6C, 1 << 7, 0); + }
int spi_disable_blockprotect_at25fs040(struct flashctx *flash) { - uint8_t status; - int result; - - status = spi_read_status_register(flash); - /* If block protection is disabled, stop here. */ - if ((status & 0x7c) == 0) - return 0; - - msg_cdbg("Some block protection in effect, disabling... "); - if (status & (1 << 7)) { - msg_cdbg("Need to disable Status Register Write Protect\n"); - /* Clear bit 7 (WPEN). */ - result = spi_write_status_register(flash, status & ~(1 << 7)); - if (result) { - msg_cerr("spi_write_status_register failed.\n"); - return result; - } - } - /* Global unprotect. Make sure to mask WPEN as well. */ - result = spi_write_status_register(flash, status & ~0xfc); - if (result) { - msg_cerr("spi_write_status_register failed.\n"); - return result; - } - status = spi_read_status_register(flash); - if ((status & 0x7c) != 0) { - msg_cerr("Block protection could not be disabled!\n"); - return 1; - } - msg_cdbg("done.\n"); - return 0; + return spi_disable_blockprotect_generic(flash, 0x7C, 1 << 7, 0); }
/* === SST === */