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[v2,2/8] mtd: add a helper to get the supported features for ONFI nand

Message ID 1366616878-29481-3-git-send-email-b32955@freescale.com
State New, archived
Headers show

Commit Message

Huang Shijie April 22, 2013, 7:47 a.m. UTC 
From: Huang Shijie <shijie8@gmail.com>

add a helper to get the supported features for ONFI nand.
Also add the neccessary macros.

Signed-off-by: Huang Shijie <b32955@freescale.com>
---
 include/linux/mtd/nand.h |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

Comments

Brian Norris April 22, 2013, 9:04 p.m. UTC | #1 
On Mon, Apr 22, 2013 at 12:47 AM, Huang Shijie <b32955@freescale.com> wrote:
> From: Huang Shijie <shijie8@gmail.com>
>
> add a helper to get the supported features for ONFI nand.
> Also add the neccessary macros.
>
> Signed-off-by: Huang Shijie <b32955@freescale.com>
> ---
>  include/linux/mtd/nand.h |   13 +++++++++++++
>  1 files changed, 13 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
> index 210bf36..122322c 100644
> --- a/include/linux/mtd/nand.h
> +++ b/include/linux/mtd/nand.h
> @@ -202,6 +202,11 @@ typedef enum {
>  /* Keep gcc happy */
>  struct nand_chip;
>
> +/* ONFI features */
> +#define ONFI_FEATURE_16_BIT_BUS                (1 << 0)
> +#define ONFI_FEATURE_EXT_PARAM_PAGE    (1 << 7)
> +#define ONFI_FEATURE_UNKNOWN           (1 << 15)

Where did you get the UNKNOWN field from? Bit 15 looks like a reserved
field (in ONFI 3.1, at least) and certainly does *not* represent a
null value. Instead, I think it does not need a macro at all, and we
can just use 0 for non-ONFI chips.

>  /* ONFI timing mode, used in both asynchronous and synchronous mode */
>  #define ONFI_TIMING_MODE_0             (1 << 0)
>  #define ONFI_TIMING_MODE_1             (1 << 1)
> @@ -750,6 +755,14 @@ struct platform_nand_chip *get_platform_nandchip(struct mtd_info *mtd)
>         return chip->priv;
>  }
>
> +/* return the supported features. */
> +static inline int onfi_feature(struct nand_chip *chip)
> +{
> +       if (!chip->onfi_version)
> +               return ONFI_FEATURE_UNKNOWN;

As noted above, just this macro is incorrect.

> +       return le16_to_cpu(chip->onfi_params.features);

Just make the whole function:

return chip->onfi_version ? le16_to_cpu(chip->onfi_params.features) : 0;

It is up to the caller to ensure that they don't rely on the returned
value for non-ONFI chips.

> +}
> +
>  /* return the supported asynchronous timing mode. */
>  static inline int onfi_get_async_timing_mode(struct nand_chip *chip)
>  {

Brian
Huang Shijie April 23, 2013, 2:49 a.m. UTC | #2 
于 2013年04月23日 05:04, Brian Norris 写道:
> return chip->onfi_version ? le16_to_cpu(chip->onfi_params.features) : 0;
it's ok to me. I will use 0 as the unknow feature in the next version.

thanks
Huang Shijie
diff mbox

Patch

diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 210bf36..122322c 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -202,6 +202,11 @@  typedef enum {
 /* Keep gcc happy */
 struct nand_chip;
 
+/* ONFI features */
+#define ONFI_FEATURE_16_BIT_BUS		(1 << 0)
+#define ONFI_FEATURE_EXT_PARAM_PAGE	(1 << 7)
+#define ONFI_FEATURE_UNKNOWN		(1 << 15)
+
 /* ONFI timing mode, used in both asynchronous and synchronous mode */
 #define ONFI_TIMING_MODE_0		(1 << 0)
 #define ONFI_TIMING_MODE_1		(1 << 1)
@@ -750,6 +755,14 @@  struct platform_nand_chip *get_platform_nandchip(struct mtd_info *mtd)
 	return chip->priv;
 }
 
+/* return the supported features. */
+static inline int onfi_feature(struct nand_chip *chip)
+{
+	if (!chip->onfi_version)
+		return ONFI_FEATURE_UNKNOWN;
+	return le16_to_cpu(chip->onfi_params.features);
+}
+
 /* return the supported asynchronous timing mode. */
 static inline int onfi_get_async_timing_mode(struct nand_chip *chip)
 {