From patchwork Thu Sep 13 06:58:00 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [v2,9/9] mtd: gpmi: initialize the timing registers only one time Date: Wed, 12 Sep 2012 20:58:00 -0000 From: Huang Shijie X-Patchwork-Id: 183529 Message-Id: <1347519480-31106-10-git-send-email-b32955@freescale.com> To: Cc: vikram186@gmail.com, Huang Shijie , linux-mtd@lists.infradead.org, shawn.guo@linaro.org, dwmw2@infradead.org, linux-arm-kernel@lists.infradead.org The current code initializes the timing registers at very time we call the gpmi_begin(). This really wastes the cpu cycles. Add a new flag to let the gpmi driver initializes the timing registers only one time. Signed-off-by: Huang Shijie --- drivers/mtd/nand/gpmi-nand/gpmi-lib.c | 8 ++++++++ drivers/mtd/nand/gpmi-nand/gpmi-nand.h | 1 + 2 files changed, 9 insertions(+), 0 deletions(-) diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c index c036e51..3502acc 100644 --- a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c +++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c @@ -914,6 +914,9 @@ static int enable_edo_mode(struct gpmi_nand_data *this, int mode) rate = (mode == 5) ? 100000000 : 80000000; clk_set_rate(r->clock[0], rate); + /* Let the gpmi_begin() re-compute the timing again. */ + this->flags &= ~GPMI_TIMING_INIT_OK; + this->flags |= GPMI_ASYNC_EDO_ENABLED; this->timing_mode = mode; dev_info(this->dev, "enable the asynchronous EDO mode %d\n", mode); @@ -964,6 +967,11 @@ void gpmi_begin(struct gpmi_nand_data *this) goto err_out; } + /* Only initialize the timing once */ + if (this->flags & GPMI_TIMING_INIT_OK) + return; + this->flags |= GPMI_TIMING_INIT_OK; + if (this->flags & GPMI_ASYNC_EDO_ENABLED) gpmi_compute_edo_timing(this, &hw); else diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h index 5b6d546..7ac25c1 100644 --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h @@ -124,6 +124,7 @@ struct nand_timing { struct gpmi_nand_data { /* flags */ #define GPMI_ASYNC_EDO_ENABLED (1 << 0) +#define GPMI_TIMING_INIT_OK (1 << 1) int flags; /* System Interface */