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 <computersforpeace@gmail.com> Here is the commit details: "mtd: spi-nor: refactor block protection functions" (sha1: 62593cf40b23b523b9fc9334ca61ba6c595ebb09) Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com> Signed-off-by: Jagan Teki <jteki@openedev.com> Reviewed-by: Tom Rini <trini@konsulko.com> Reviewed-by: Heiko Schocher <hs@denx.de> Reviewed-by: Jagan Teki <jteki@openedev.com> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
This commit is contained in:
Fabio Estevam
Tom Rini
parent
2d2f490dd5
commit
41b358d7a7
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@ -105,6 +105,9 @@ enum spi_nor_option_flags {
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#define STATUS_QEB_WINSPAN (1 << 1)
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#define STATUS_QEB_MXIC (1 << 6)
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#define STATUS_PEC (1 << 7)
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#define SR_BP0 BIT(2) /* Block protect 0 */
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#define SR_BP1 BIT(3) /* Block protect 1 */
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#define SR_BP2 BIT(4) /* Block protect 2 */
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/* Flash timeout values */
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#define SPI_FLASH_PROG_TIMEOUT (2 * CONFIG_SYS_HZ)
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@ -15,6 +15,7 @@
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#include <spi_flash.h>
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#include <watchdog.h>
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#include <linux/compiler.h>
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#include <linux/log2.h>
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#include "sf_internal.h"
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@ -565,3 +566,172 @@ int sst_write_bp(struct spi_flash *flash, u32 offset, size_t len,
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return ret;
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}
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#endif
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#ifdef CONFIG_SPI_FLASH_STMICRO
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static void stm_get_locked_range(struct spi_flash *flash, u8 sr, loff_t *ofs,
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u32 *len)
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{
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u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
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int shift = ffs(mask) - 1;
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int pow;
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if (!(sr & mask)) {
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/* No protection */
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*ofs = 0;
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*len = 0;
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} else {
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pow = ((sr & mask) ^ mask) >> shift;
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*len = flash->size >> pow;
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*ofs = flash->size - *len;
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}
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}
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/*
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* Return 1 if the entire region is locked, 0 otherwise
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*/
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static int stm_is_locked_sr(struct spi_flash *flash, loff_t ofs, u32 len,
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u8 sr)
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{
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loff_t lock_offs;
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u32 lock_len;
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stm_get_locked_range(flash, sr, &lock_offs, &lock_len);
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return (ofs + len <= lock_offs + lock_len) && (ofs >= lock_offs);
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}
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/*
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* Check if a region of the flash is (completely) locked. See stm_lock() for
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* more info.
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*
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* Returns 1 if entire region is locked, 0 if any portion is unlocked, and
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* negative on errors.
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*/
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int stm_is_locked(struct spi_flash *flash, loff_t ofs, u32 len)
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{
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int status;
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u8 sr;
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status = spi_flash_cmd_read_status(flash, &sr);
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if (status < 0)
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return status;
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return stm_is_locked_sr(flash, ofs, len, sr);
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}
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/*
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* Lock a region of the flash. Compatible with ST Micro and similar flash.
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* Supports only the block protection bits BP{0,1,2} in the status register
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* (SR). Does not support these features found in newer SR bitfields:
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* - TB: top/bottom protect - only handle TB=0 (top protect)
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* - SEC: sector/block protect - only handle SEC=0 (block protect)
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* - CMP: complement protect - only support CMP=0 (range is not complemented)
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*
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* Sample table portion for 8MB flash (Winbond w25q64fw):
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*
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* SEC | TB | BP2 | BP1 | BP0 | Prot Length | Protected Portion
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* --------------------------------------------------------------------------
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* X | X | 0 | 0 | 0 | NONE | NONE
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* 0 | 0 | 0 | 0 | 1 | 128 KB | Upper 1/64
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* 0 | 0 | 0 | 1 | 0 | 256 KB | Upper 1/32
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* 0 | 0 | 0 | 1 | 1 | 512 KB | Upper 1/16
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* 0 | 0 | 1 | 0 | 0 | 1 MB | Upper 1/8
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* 0 | 0 | 1 | 0 | 1 | 2 MB | Upper 1/4
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* 0 | 0 | 1 | 1 | 0 | 4 MB | Upper 1/2
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* X | X | 1 | 1 | 1 | 8 MB | ALL
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*
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* Returns negative on errors, 0 on success.
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*/
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int stm_lock(struct spi_flash *flash, u32 ofs, size_t len)
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{
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u8 status_old, status_new;
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u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
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u8 shift = ffs(mask) - 1, pow, val;
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spi_flash_cmd_read_status(flash, &status_old);
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/* SPI NOR always locks to the end */
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if (ofs + len != flash->size) {
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/* Does combined region extend to end? */
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if (!stm_is_locked_sr(flash, ofs + len, flash->size - ofs - len,
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status_old))
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return -EINVAL;
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len = flash->size - ofs;
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}
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/*
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* Need smallest pow such that:
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*
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* 1 / (2^pow) <= (len / size)
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*
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* so (assuming power-of-2 size) we do:
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*
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* pow = ceil(log2(size / len)) = log2(size) - floor(log2(len))
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*/
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pow = ilog2(flash->size) - ilog2(len);
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val = mask - (pow << shift);
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if (val & ~mask)
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return -EINVAL;
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/* Don't "lock" with no region! */
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if (!(val & mask))
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return -EINVAL;
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status_new = (status_old & ~mask) | val;
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/* Only modify protection if it will not unlock other areas */
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if ((status_new & mask) <= (status_old & mask))
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return -EINVAL;
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spi_flash_cmd_write_status(flash, status_new);
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return 0;
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}
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/*
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* Unlock a region of the flash. See stm_lock() for more info
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*
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* Returns negative on errors, 0 on success.
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*/
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int stm_unlock(struct spi_flash *flash, u32 ofs, size_t len)
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{
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uint8_t status_old, status_new;
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u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
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u8 shift = ffs(mask) - 1, pow, val;
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spi_flash_cmd_read_status(flash, &status_old);
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/* Cannot unlock; would unlock larger region than requested */
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if (stm_is_locked_sr(flash, status_old, ofs - flash->erase_size,
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flash->erase_size))
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return -EINVAL;
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/*
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* Need largest pow such that:
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*
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* 1 / (2^pow) >= (len / size)
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*
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* so (assuming power-of-2 size) we do:
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*
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* pow = floor(log2(size / len)) = log2(size) - ceil(log2(len))
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*/
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pow = ilog2(flash->size) - order_base_2(flash->size - (ofs + len));
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if (ofs + len == flash->size) {
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val = 0; /* fully unlocked */
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} else {
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val = mask - (pow << shift);
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/* Some power-of-two sizes are not supported */
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if (val & ~mask)
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return -EINVAL;
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}
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status_new = (status_old & ~mask) | val;
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/* Only modify protection if it will not lock other areas */
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if ((status_new & mask) >= (status_old & mask))
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return -EINVAL;
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spi_flash_cmd_write_status(flash, status_new);
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return 0;
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}
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#endif /* CONFIG_SPI_FLASH_STMICRO */
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