[U-Boot] [PATCH 1/2] mtd: nand: omap_gpmc: Add CONFIG_SYS_NAND_USE_READY to enable ready/busy
By defining CONFIG_SYS_NAND_USE_READY the GPMC NAND driver makes use of the ready pin / signal for busy / ready detection. This function is already available but currently only used in SPL. I don't see a reason to not use it in the main U-Boot as well. As it increases the NAND performance.
I'm making it configurable, so that boards that might now have this pin connected are still supported.
Signed-off-by: Stefan Roese sr@denx.de Cc: Tom Rini trini@ti.com Cc: Scott Wood scottwood@freescale.com Cc: Roger Meier r.meier@siemens.com Cc: Samuel Egli samuel.egli@siemens.com --- README | 5 +++++ drivers/mtd/nand/omap_gpmc.c | 20 +++++++++++++++++--- 2 files changed, 22 insertions(+), 3 deletions(-)
diff --git a/README b/README index c3a9dfc..420c14b 100644 --- a/README +++ b/README @@ -4731,6 +4731,11 @@ Low Level (hardware related) configuration options: - drivers/mtd/nand/ndfc.c - drivers/mtd/nand/mxc_nand.c
+- CONFIG_SYS_NAND_USE_READY + Defined if a ready/busy pin is available on this board + which can be used to determine the state of the NAND + chip. Currently used on the OMAP/AM33xx NAND driver. + - CONFIG_SYS_NDFC_EBC0_CFG Sets the EBC0_CFG register for the NDFC. If not defined a default value will be used. diff --git a/drivers/mtd/nand/omap_gpmc.c b/drivers/mtd/nand/omap_gpmc.c index 40d6705..8ca95d3 100644 --- a/drivers/mtd/nand/omap_gpmc.c +++ b/drivers/mtd/nand/omap_gpmc.c @@ -23,6 +23,16 @@ /* 4 bit padding to make byte aligned, 56 = 52 + 4 */ #define BCH4_BIT_PAD 4
+/* + * All OMAP / AM33xx SPL builds already use the ready / busy pin. + * So lets enable this new define to use this signal for SPL. This + * makes the check in the code easier since its reduced to a single + * macro. + */ +#ifdef CONFIG_SPL_BUILD +#define CONFIG_SYS_NAND_USE_READY +#endif + #ifdef CONFIG_BCH static u8 bch8_polynomial[] = {0xef, 0x51, 0x2e, 0x09, 0xed, 0x93, 0x9a, 0xc2, 0x97, 0x79, 0xe5, 0x24, 0xb5}; @@ -73,9 +83,9 @@ static void omap_nand_hwcontrol(struct mtd_info *mtd, int32_t cmd, writeb(cmd, this->IO_ADDR_W); }
-#ifdef CONFIG_SPL_BUILD +#ifdef CONFIG_SYS_NAND_USE_READY /* Check wait pin as dev ready indicator */ -static int omap_spl_dev_ready(struct mtd_info *mtd) +static int omap_dev_ready(struct mtd_info *mtd) { return gpmc_cfg->status & (1 << 8); } @@ -887,7 +897,11 @@ int board_nand_init(struct nand_chip *nand) nand->read_buf = nand_read_buf16; else nand->read_buf = nand_read_buf; - nand->dev_ready = omap_spl_dev_ready; #endif + +#ifdef CONFIG_SYS_NAND_USE_READY + nand->dev_ready = omap_dev_ready; +#endif + return 0; }
Testing showed a small perfomance gain by using this ready pin to detect the NAND chip state. Here the values tested on Draco with Hynix 4GBit NAND:
Without NAND ready pin:
U-Boot# time nand read 80400000 0 400000
NAND read: device 0 offset 0x0, size 0x400000 4194304 bytes read: OK
time: 2.947 seconds, 2947 ticks
With NAND ready pin:
U-Boot# time nand read 80400000 0 400000
NAND read: device 0 offset 0x0, size 0x400000 4194304 bytes read: OK
time: 2.795 seconds, 2795 ticks
So an increase of approx. 5%.
Signed-off-by: Stefan Roese sr@denx.de Cc: Tom Rini trini@ti.com Cc: Scott Wood scottwood@freescale.com Cc: Roger Meier r.meier@siemens.com Cc: Samuel Egli samuel.egli@siemens.com --- include/configs/siemens-am33x-common.h | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/include/configs/siemens-am33x-common.h b/include/configs/siemens-am33x-common.h index 0d5dba1..9f84e09 100644 --- a/include/configs/siemens-am33x-common.h +++ b/include/configs/siemens-am33x-common.h @@ -466,6 +466,8 @@ /* CS0 */ #define CONFIG_SYS_MAX_NAND_DEVICE 1 /* Max number of NAND devices */ +#define CONFIG_SYS_NAND_USE_READY + #if !defined(CONFIG_SPI_BOOT) #undef CONFIG_ENV_IS_NOWHERE #define CONFIG_ENV_IS_IN_NAND
On Wed, 2014-11-12 at 11:53 +0100, Stefan Roese wrote:
By defining CONFIG_SYS_NAND_USE_READY the GPMC NAND driver makes use of the ready pin / signal for busy / ready detection. This function is already available but currently only used in SPL. I don't see a reason to not use it in the main U-Boot as well. As it increases the NAND performance.
I'm making it configurable, so that boards that might now have this pin connected are still supported.
Signed-off-by: Stefan Roese sr@denx.de Cc: Tom Rini trini@ti.com Cc: Scott Wood scottwood@freescale.com Cc: Roger Meier r.meier@siemens.com Cc: Samuel Egli samuel.egli@siemens.com
README | 5 +++++ drivers/mtd/nand/omap_gpmc.c | 20 +++++++++++++++++--- 2 files changed, 22 insertions(+), 3 deletions(-)
diff --git a/README b/README index c3a9dfc..420c14b 100644 --- a/README +++ b/README @@ -4731,6 +4731,11 @@ Low Level (hardware related) configuration options: - drivers/mtd/nand/ndfc.c - drivers/mtd/nand/mxc_nand.c
+- CONFIG_SYS_NAND_USE_READY
Defined if a ready/busy pin is available on this boardwhich can be used to determine the state of the NANDchip. Currently used on the OMAP/AM33xx NAND driver.
New symbols should be done in kconfig.
Is this really something that ought to be a generic symbol, rather than OMAP-specific?
-Scott
On Wed, Nov 12, 2014 at 11:53:11AM +0100, Stefan Roese wrote:
By defining CONFIG_SYS_NAND_USE_READY the GPMC NAND driver makes use of the ready pin / signal for busy / ready detection. This function is already available but currently only used in SPL. I don't see a reason to not use it in the main U-Boot as well. As it increases the NAND performance.
I'm making it configurable, so that boards that might now have this pin connected are still supported.
I don't think we need to make this configurable. I think it's always been an oversight since we've always done this in NAND for SPL and I can't think of any boards that do support NAND but don't support booting from NAND in U-Boot.
participants (3)
-
Scott Wood -
Stefan Roese -
Tom Rini