From 41b358d7a7c9f29eca4a439fba0ae679100a9ad5 Mon Sep 17 00:00:00 2001 From: Fabio Estevam Date: Thu, 5 Nov 2015 12:43:41 -0200 Subject: [PATCH] sf: Add SPI protection mechanism from the kernel Add the SPI NOR protection mechanism from the kernel. This code is based on the work from Brian Norris Here is the commit details: "mtd: spi-nor: refactor block protection functions" (sha1: 62593cf40b23b523b9fc9334ca61ba6c595ebb09) Signed-off-by: Fabio Estevam Signed-off-by: Jagan Teki Reviewed-by: Tom Rini Reviewed-by: Heiko Schocher Reviewed-by: Jagan Teki Signed-off-by: Fabio Estevam --- drivers/mtd/spi/sf_internal.h | 3 + drivers/mtd/spi/sf_ops.c | 170 ++++++++++++++++++++++++++++++++++ 2 files changed, 173 insertions(+) diff --git a/drivers/mtd/spi/sf_internal.h b/drivers/mtd/spi/sf_internal.h index 8a3e5ec3d7..ac493f1f76 100644 --- a/drivers/mtd/spi/sf_internal.h +++ b/drivers/mtd/spi/sf_internal.h @@ -105,6 +105,9 @@ enum spi_nor_option_flags { #define STATUS_QEB_WINSPAN (1 << 1) #define STATUS_QEB_MXIC (1 << 6) #define STATUS_PEC (1 << 7) +#define SR_BP0 BIT(2) /* Block protect 0 */ +#define SR_BP1 BIT(3) /* Block protect 1 */ +#define SR_BP2 BIT(4) /* Block protect 2 */ /* Flash timeout values */ #define SPI_FLASH_PROG_TIMEOUT (2 * CONFIG_SYS_HZ) diff --git a/drivers/mtd/spi/sf_ops.c b/drivers/mtd/spi/sf_ops.c index f2a9244a14..6c87ba60fd 100644 --- a/drivers/mtd/spi/sf_ops.c +++ b/drivers/mtd/spi/sf_ops.c @@ -15,6 +15,7 @@ #include #include #include +#include #include "sf_internal.h" @@ -565,3 +566,172 @@ int sst_write_bp(struct spi_flash *flash, u32 offset, size_t len, return ret; } #endif + +#ifdef CONFIG_SPI_FLASH_STMICRO +static void stm_get_locked_range(struct spi_flash *flash, u8 sr, loff_t *ofs, + u32 *len) +{ + u8 mask = SR_BP2 | SR_BP1 | SR_BP0; + int shift = ffs(mask) - 1; + int pow; + + if (!(sr & mask)) { + /* No protection */ + *ofs = 0; + *len = 0; + } else { + pow = ((sr & mask) ^ mask) >> shift; + *len = flash->size >> pow; + *ofs = flash->size - *len; + } +} + +/* + * Return 1 if the entire region is locked, 0 otherwise + */ +static int stm_is_locked_sr(struct spi_flash *flash, loff_t ofs, u32 len, + u8 sr) +{ + loff_t lock_offs; + u32 lock_len; + + stm_get_locked_range(flash, sr, &lock_offs, &lock_len); + + return (ofs + len <= lock_offs + lock_len) && (ofs >= lock_offs); +} + +/* + * Check if a region of the flash is (completely) locked. See stm_lock() for + * more info. + * + * Returns 1 if entire region is locked, 0 if any portion is unlocked, and + * negative on errors. + */ +int stm_is_locked(struct spi_flash *flash, loff_t ofs, u32 len) +{ + int status; + u8 sr; + + status = spi_flash_cmd_read_status(flash, &sr); + if (status < 0) + return status; + + return stm_is_locked_sr(flash, ofs, len, sr); +} + +/* + * Lock a region of the flash. Compatible with ST Micro and similar flash. + * Supports only the block protection bits BP{0,1,2} in the status register + * (SR). Does not support these features found in newer SR bitfields: + * - TB: top/bottom protect - only handle TB=0 (top protect) + * - SEC: sector/block protect - only handle SEC=0 (block protect) + * - CMP: complement protect - only support CMP=0 (range is not complemented) + * + * Sample table portion for 8MB flash (Winbond w25q64fw): + * + * SEC | TB | BP2 | BP1 | BP0 | Prot Length | Protected Portion + * -------------------------------------------------------------------------- + * X | X | 0 | 0 | 0 | NONE | NONE + * 0 | 0 | 0 | 0 | 1 | 128 KB | Upper 1/64 + * 0 | 0 | 0 | 1 | 0 | 256 KB | Upper 1/32 + * 0 | 0 | 0 | 1 | 1 | 512 KB | Upper 1/16 + * 0 | 0 | 1 | 0 | 0 | 1 MB | Upper 1/8 + * 0 | 0 | 1 | 0 | 1 | 2 MB | Upper 1/4 + * 0 | 0 | 1 | 1 | 0 | 4 MB | Upper 1/2 + * X | X | 1 | 1 | 1 | 8 MB | ALL + * + * Returns negative on errors, 0 on success. + */ +int stm_lock(struct spi_flash *flash, u32 ofs, size_t len) +{ + u8 status_old, status_new; + u8 mask = SR_BP2 | SR_BP1 | SR_BP0; + u8 shift = ffs(mask) - 1, pow, val; + + spi_flash_cmd_read_status(flash, &status_old); + + /* SPI NOR always locks to the end */ + if (ofs + len != flash->size) { + /* Does combined region extend to end? */ + if (!stm_is_locked_sr(flash, ofs + len, flash->size - ofs - len, + status_old)) + return -EINVAL; + len = flash->size - ofs; + } + + /* + * Need smallest pow such that: + * + * 1 / (2^pow) <= (len / size) + * + * so (assuming power-of-2 size) we do: + * + * pow = ceil(log2(size / len)) = log2(size) - floor(log2(len)) + */ + pow = ilog2(flash->size) - ilog2(len); + val = mask - (pow << shift); + if (val & ~mask) + return -EINVAL; + + /* Don't "lock" with no region! */ + if (!(val & mask)) + return -EINVAL; + + status_new = (status_old & ~mask) | val; + + /* Only modify protection if it will not unlock other areas */ + if ((status_new & mask) <= (status_old & mask)) + return -EINVAL; + + spi_flash_cmd_write_status(flash, status_new); + + return 0; +} + +/* + * Unlock a region of the flash. See stm_lock() for more info + * + * Returns negative on errors, 0 on success. + */ +int stm_unlock(struct spi_flash *flash, u32 ofs, size_t len) +{ + uint8_t status_old, status_new; + u8 mask = SR_BP2 | SR_BP1 | SR_BP0; + u8 shift = ffs(mask) - 1, pow, val; + + spi_flash_cmd_read_status(flash, &status_old); + + /* Cannot unlock; would unlock larger region than requested */ + if (stm_is_locked_sr(flash, status_old, ofs - flash->erase_size, + flash->erase_size)) + return -EINVAL; + /* + * Need largest pow such that: + * + * 1 / (2^pow) >= (len / size) + * + * so (assuming power-of-2 size) we do: + * + * pow = floor(log2(size / len)) = log2(size) - ceil(log2(len)) + */ + pow = ilog2(flash->size) - order_base_2(flash->size - (ofs + len)); + if (ofs + len == flash->size) { + val = 0; /* fully unlocked */ + } else { + val = mask - (pow << shift); + /* Some power-of-two sizes are not supported */ + if (val & ~mask) + return -EINVAL; + } + + status_new = (status_old & ~mask) | val; + + /* Only modify protection if it will not lock other areas */ + if ((status_new & mask) >= (status_old & mask)) + return -EINVAL; + + spi_flash_cmd_write_status(flash, status_new); + + return 0; +} +#endif /* CONFIG_SPI_FLASH_STMICRO */