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mmc: core: production year for eMMC 4.41 and later

PATCH In review Romain Izard 2 participants 2 messages Jun 14, 2013 – Jun 27, 2013 MMC, SD and SDIO

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Romain Izard

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PATCH 1/1 mmc: core: production year for eMMC 4.41 and later

The field containing the production date in the CID register only uses 4 bits to encode the year, starting from 1997 in the original standard. In 2013, the production year field contains 0, and the kernel reports a 1997 production date.

The eMMC 4.51 specification adds a new interpretation rule. For all devices implementing the 4.41 specification or later, the production year field will be interpreted as a value between 2010 and 2025, with 0 corresponding to 2013.

Signed-off-by Romain Izard <[email protected]>
---
 drivers/mmc/core/mmc.c | 4 ++++
 1 file changed, 4 insertions(+)
drivers/mmc/core/mmc.c +4 -0
index 3a69b94..3914523 100644
@@ -482,6 +482,10 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
 	}
 
 	if (card->ext_csd.rev >= 5) {
+		/* Adjust production date as per JEDEC JESD84-B451 */
+		if (card->cid.year < 2010)
+			card->cid.year += 16;
+
 		/* check whether the eMMC card supports BKOPS */
 		if (ext_csd[EXT_CSD_BKOPS_SUPPORT] & 0x1) {
 			card->ext_csd.bkops = 1;
Signature · 1 line
1.8.1.2
#1 lore raw

Hi Romain,

Quoted 20 lines · Romain Izard

The field containing the production date in the CID register only uses 4 bits to encode the year, starting from 1997 in the original standard. In 2013, the production year field contains 0, and the kernel reports a 1997 production date.

The eMMC 4.51 specification adds a new interpretation rule. For all devices implementing the 4.41 specification or later, the production year field will be interpreted as a value between 2010 and 2025, with 0 corresponding to 2013.

Signed-off-by Romain Izard <[email protected]>
---
 drivers/mmc/core/mmc.c | 4 ++++
 1 file changed, 4 insertions(+)
drivers/mmc/core/mmc.c +0 -0
index 3a69b94..3914523 100644

drivers/mmc/core/mmc.c static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd) · line 491

Quoted 10 lines
drivers/mmc/core/mmc.c +4 -0
@@ -482,6 +482,10 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
 	}
 
 	if (card->ext_csd.rev >= 5) {
+		/* Adjust production date as per JEDEC JESD84-B451 */
+		if (card->cid.year < 2010)
+			card->cid.year += 16;
+
 		/* check whether the eMMC card supports BKOPS */
 		if (ext_csd[EXT_CSD_BKOPS_SUPPORT] & 0x1) {
 			card->ext_csd.bkops = 1;

Thanks, pushed to mmc-next for 3.11.

- Chris.

Signature · 2 lines
Chris Ball   <[email protected]>   <http://printf.net/>
One Laptop Per Child