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[nvs] Allow for non-volatile storage devices without block boundaries
Signed-off-by: Michael Brown <mcb30@ipxe.org>
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mcb30 committed Jan 11, 2011
1 parent 17b6a3c commit 8f8b55f
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Showing 2 changed files with 32 additions and 17 deletions.
48 changes: 32 additions & 16 deletions src/drivers/nvs/nvs.c
Expand Up @@ -30,6 +30,34 @@ FILE_LICENCE ( GPL2_OR_LATER );
*
*/

/**
* Calculate length up to next block boundary
*
* @v nvs NVS device
* @v address Starting address
* @v max_len Maximum length
* @ret len Length to use, stopping at block boundaries
*/
static size_t nvs_frag_len ( struct nvs_device *nvs, unsigned int address,
size_t max_len ) {
size_t frag_len;

/* If there are no block boundaries, return the maximum length */
if ( ! nvs->block_size )
return max_len;

/* Calculate space remaining up to next block boundary */
frag_len = ( ( nvs->block_size -
( address & ( nvs->block_size - 1 ) ) )
<< nvs->word_len_log2 );

/* Limit to maximum length */
if ( max_len < frag_len )
return max_len;

return frag_len;
}

/**
* Read from non-volatile storage device
*
Expand All @@ -51,14 +79,8 @@ int nvs_read ( struct nvs_device *nvs, unsigned int address,

while ( len ) {

/* Calculate space remaining up to next block boundary */
frag_len = ( ( nvs->block_size -
( address & ( nvs->block_size - 1 ) ) )
<< nvs->word_len_log2 );

/* Limit to space remaining in buffer */
if ( frag_len > len )
frag_len = len;
/* Calculate length to read, stopping at block boundaries */
frag_len = nvs_frag_len ( nvs, address, len );

/* Read this portion of the buffer from the device */
if ( ( rc = nvs->read ( nvs, address, data, frag_len ) ) != 0 )
Expand Down Expand Up @@ -122,14 +144,8 @@ int nvs_write ( struct nvs_device *nvs, unsigned int address,

while ( len ) {

/* Calculate space remaining up to next block boundary */
frag_len = ( ( nvs->block_size -
( address & ( nvs->block_size - 1 ) ) )
<< nvs->word_len_log2 );

/* Limit to space remaining in buffer */
if ( frag_len > len )
frag_len = len;
/* Calculate length to write, stopping at block boundaries */
frag_len = nvs_frag_len ( nvs, address, len );

/* Write this portion of the buffer to the device */
if ( ( rc = nvs->write ( nvs, address, data, frag_len ) ) != 0)
Expand Down
1 change: 0 additions & 1 deletion src/drivers/nvs/nvsvpd.c
Expand Up @@ -111,7 +111,6 @@ int nvs_vpd_init ( struct nvs_vpd_device *nvsvpd, struct pci_device *pci,
}

/* Initialise NVS device */
nvsvpd->nvs.block_size = 1;
nvsvpd->nvs.size = len;
nvsvpd->nvs.read = nvs_vpd_read;
nvsvpd->nvs.write = nvs_vpd_write;
Expand Down

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