[U-Boot] [PATCH v5 1/2] SPI Flash: add support of sst26wf* flash ICs protection ops

[Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>]

Hi Jagan,

Maybe you have any comments or remarks about this patch? And if you don't could you please apply it.
Thanks!

On Tue, 2018-04-10 at 14:40 +0300, Eugeniy Paltsev wrote:
> sst26wf flash series block protection implementation differs
> from other SST series, so add specific implementation
> flash_lock/flash_unlock/flash_is_locked functions for sst26wf
> flash ICs.
> 
> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
> ---
> Changes v4->v5:
>  * Return EACCES when flash is locked instead of custom define (SF_LOCKED)
>  * Add SST26_CTL_* prefix to sst27 lock ops enum.
>  * Move all sst26 code inside of existing CONFIG_SPI_FLASH_SST #ifdef.
> 
> Changes v3->v4:
>  * Make sst26_process_bpr() and sst26_lock_ctl() functions static.
> 
> Changes v2->v3:
>  * Move SST26 command defenition to sf_internal.h
>  * Merge sst26_set_bpr, sst26_clear_bpr and sst26_check_bpr functions
>    into single sst26_process_bpr function.
>  * Use SF_UNLOCKED/SF_LOCKED instead of magic numbers in
>    sst26_lock_ctl()
> 
> Changes v1->v2:
>  * Use generic defines from linux/sizes.h instead of custom ones.
> 
>  drivers/mtd/spi/sf_internal.h |  13 ++++
>  drivers/mtd/spi/spi_flash.c   | 168 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 181 insertions(+)
> 
> diff --git a/drivers/mtd/spi/sf_internal.h b/drivers/mtd/spi/sf_internal.h
> index 839cdbe1b0..614a293234 100644
> --- a/drivers/mtd/spi/sf_internal.h
> +++ b/drivers/mtd/spi/sf_internal.h
> @@ -87,6 +87,19 @@ enum spi_nor_option_flags {
>  
>  /* SST specific */
>  #ifdef CONFIG_SPI_FLASH_SST
> +#define SST26_CMD_READ_BPR		0x72
> +#define SST26_CMD_WRITE_BPR		0x42
> +
> +#define SST26_BPR_8K_NUM		4
> +#define SST26_MAX_BPR_REG_LEN		(18 + 1)
> +#define SST26_BOUND_REG_SIZE		((32 + SST26_BPR_8K_NUM * 8) * SZ_1K)
> +
> +enum lock_ctl {
> +	SST26_CTL_LOCK,
> +	SST26_CTL_UNLOCK,
> +	SST26_CTL_CHECK
> +};
> +
>  # define CMD_SST_BP		0x02    /* Byte Program */
>  # define CMD_SST_AAI_WP		0xAD	/* Auto Address Incr Word Program */
>  
> diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
> index 2e61685d3e..5e5bd5d533 100644
> --- a/drivers/mtd/spi/spi_flash.c
> +++ b/drivers/mtd/spi/spi_flash.c
> @@ -16,6 +16,7 @@
>  #include <spi.h>
>  #include <spi_flash.h>
>  #include <linux/log2.h>
> +#include <linux/sizes.h>
>  #include <dma.h>
>  
>  #include "sf_internal.h"
> @@ -541,6 +542,164 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
>  }
>  
>  #ifdef CONFIG_SPI_FLASH_SST
> +static bool sst26_process_bpr(u32 bpr_size, u8 *cmd, u32 bit, enum lock_ctl ctl)
> +{
> +	switch (ctl) {
> +		case SST26_CTL_LOCK:
> +			cmd[bpr_size - (bit / 8) - 1] |= BIT(bit % 8);
> +			break;
> +		case SST26_CTL_UNLOCK:
> +			cmd[bpr_size - (bit / 8) - 1] &= ~BIT(bit % 8);
> +			break;
> +		case SST26_CTL_CHECK:
> +			return !!(cmd[bpr_size - (bit / 8) - 1] & BIT(bit % 8));
> +	}
> +
> +	return false;
> +}
> +
> +/*
> + * sst26wf016/sst26wf032/sst26wf064 have next block protection:
> + * 4x   - 8  KByte blocks - read & write protection bits - upper addresses
> + * 1x   - 32 KByte blocks - write protection bits
> + * rest - 64 KByte blocks - write protection bits
> + * 1x   - 32 KByte blocks - write protection bits
> + * 4x   - 8  KByte blocks - read & write protection bits - lower addresses
> + *
> + * We'll support only per 64k lock/unlock so lower and upper 64 KByte region
> + * will be treated as single block.
> + */
> +
> +/*
> + * Lock, unlock or check lock status of the flash region of the flash (depending
> + * on the lock_ctl value)
> + */
> +static int sst26_lock_ctl(struct spi_flash *flash, u32 ofs, size_t len, enum lock_ctl ctl)
> +{
> +	u32 i, bpr_ptr, rptr_64k, lptr_64k, bpr_size;
> +	bool lower_64k = false, upper_64k = false;
> +	u8 cmd, bpr_buff[SST26_MAX_BPR_REG_LEN] = {};
> +	int ret;
> +
> +	/* Check length and offset for 64k alignment */
> +	if ((ofs & (SZ_64K - 1)) || (len & (SZ_64K - 1)))
> +		return -EINVAL;
> +
> +	if (ofs + len > flash->size)
> +		return -EINVAL;
> +
> +	/* SST26 family has only 16 Mbit, 32 Mbit and 64 Mbit IC */
> +	if (flash->size != SZ_2M &&
> +	    flash->size != SZ_4M &&
> +	    flash->size != SZ_8M)
> +		return -EINVAL;
> +
> +	bpr_size = 2 + (flash->size / SZ_64K / 8);
> +
> +	cmd = SST26_CMD_READ_BPR;
> +	ret = spi_flash_read_common(flash, &cmd, 1, bpr_buff, bpr_size);
> +	if (ret < 0) {
> +		printf("SF: fail to read block-protection register\n");
> +		return ret;
> +	}
> +
> +	rptr_64k = min_t(u32, ofs + len , flash->size - SST26_BOUND_REG_SIZE);
> +	lptr_64k = max_t(u32, ofs, SST26_BOUND_REG_SIZE);
> +
> +	upper_64k = ((ofs + len) > (flash->size - SST26_BOUND_REG_SIZE));
> +	lower_64k = (ofs < SST26_BOUND_REG_SIZE);
> +
> +	/* Lower bits in block-protection register are about 64k region */
> +	bpr_ptr = lptr_64k / SZ_64K - 1;
> +
> +	/* Process 64K blocks region */
> +	while (lptr_64k < rptr_64k) {
> +		if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
> +			return EACCES;
> +
> +		bpr_ptr++;
> +		lptr_64k += SZ_64K;
> +	}
> +
> +	/* 32K and 8K region bits in BPR are after 64k region bits */
> +	bpr_ptr = (flash->size - 2 * SST26_BOUND_REG_SIZE) / SZ_64K;
> +
> +	/* Process lower 32K block region */
> +	if (lower_64k)
> +		if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
> +			return EACCES;
> +
> +	bpr_ptr++;
> +
> +	/* Process upper 32K block region */
> +	if (upper_64k)
> +		if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
> +			return EACCES;
> +
> +	bpr_ptr++;
> +
> +	/* Process lower 8K block regions */
> +	for (i = 0; i < SST26_BPR_8K_NUM; i++) {
> +		if (lower_64k)
> +			if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
> +				return EACCES;
> +
> +		/* In 8K area BPR has both read and write protection bits */
> +		bpr_ptr += 2;
> +	}
> +
> +	/* Process upper 8K block regions */
> +	for (i = 0; i < SST26_BPR_8K_NUM; i++) {
> +		if (upper_64k)
> +			if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
> +				return EACCES;
> +
> +		/* In 8K area BPR has both read and write protection bits */
> +		bpr_ptr += 2;
> +	}
> +
> +	/* If we check region status we don't need to write BPR back */
> +	if (ctl == SST26_CTL_CHECK)
> +		return 0;
> +
> +	cmd = SST26_CMD_WRITE_BPR;
> +	ret = spi_flash_write_common(flash, &cmd, 1, bpr_buff, bpr_size);
> +	if (ret < 0) {
> +		printf("SF: fail to write block-protection register\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int sst26_unlock(struct spi_flash *flash, u32 ofs, size_t len)
> +{
> +	return sst26_lock_ctl(flash, ofs, len, SST26_CTL_UNLOCK);
> +}
> +
> +static int sst26_lock(struct spi_flash *flash, u32 ofs, size_t len)
> +{
> +	return sst26_lock_ctl(flash, ofs, len, SST26_CTL_LOCK);
> +}
> +
> +/*
> + * Returns EACCES (positive value) if region is locked, 0 if region is unlocked,
> + * and negative on errors.
> + */
> +static int sst26_is_locked(struct spi_flash *flash, u32 ofs, size_t len)
> +{
> +	/*
> +	 * is_locked function is used for check before reading or erasing flash
> +	 * region, so offset and length might be not 64k allighned, so adjust
> +	 * them to be 64k allighned as sst26_lock_ctl works only with 64k
> +	 * allighned regions.
> +	 */
> +	ofs -= ofs & (SZ_64K - 1);
> +	len = len & (SZ_64K - 1) ? (len & ~(SZ_64K - 1)) + SZ_64K : len;
> +
> +	return sst26_lock_ctl(flash, ofs, len, SST26_CTL_CHECK);
> +}
> +
>  static int sst_byte_write(struct spi_flash *flash, u32 offset, const void *buf)
>  {
>  	struct spi_slave *spi = flash->spi;
> @@ -1033,6 +1192,15 @@ int spi_flash_scan(struct spi_flash *flash)
>  	}
>  #endif
>  
> +/* sst26wf series block protection implementation differs from other series */
> +#if defined(CONFIG_SPI_FLASH_SST)
> +	if (JEDEC_MFR(info) == SPI_FLASH_CFI_MFR_SST && info->id[1] == 0x26) {
> +		flash->flash_lock = sst26_lock;
> +		flash->flash_unlock = sst26_unlock;
> +		flash->flash_is_locked = sst26_is_locked;
> +	}
> +#endif
> +
>  	/* Compute the flash size */
>  	flash->shift = (flash->dual_flash & SF_DUAL_PARALLEL_FLASH) ? 1 : 0;
>  	flash->page_size = info->page_size;
-- 
 Eugeniy Paltsev