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[PATCH 14/16] i2c-designware: Deferred FIFO-data-counting variables init

To: baruch@tkos.co.il, linux-i2c@vger.kernel.org
Subject: [PATCH 14/16] i2c-designware: Deferred FIFO-data-counting variables initialization
From: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Date: Tue, 13 Oct 2009 11:53:35 +0900
Cc: ben-linux@fluff.org, linux-mips@linux-mips.org, linux-arm-kernel@lists.infradead.org
In-reply-to: <4AD3E974.8080200@necel.com>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <4AD3E974.8080200@necel.com>
Sender: linux-mips-bounce@linux-mips.org
User-agent: Thunderbird 2.0.0.23 (Windows/20090812)
As the driver and hardware always process the given data in parallel,
it would be better to initialize those {tx,rx}_limit or rx_valid
variables just prior to be used.

This will help to send/receive data as much as possible.

Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
---
drivers/i2c/busses/i2c-designware.c |   10 +++++++---
1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware.c 
b/drivers/i2c/busses/i2c-designware.c
index b3152c2..f7ea032 100644
--- a/drivers/i2c/busses/i2c-designware.c
+++ b/drivers/i2c/busses/i2c-designware.c
@@ -359,8 +359,7 @@ i2c_dw_xfer_msg(struct dw_i2c_dev *dev)
{
        struct i2c_msg *msgs = dev->msgs;
        u32 intr_mask;
-       int tx_limit = dev->tx_fifo_depth - readl(dev->base + DW_IC_TXFLR);
-       int rx_limit = dev->rx_fifo_depth - readl(dev->base + DW_IC_RXFLR);
+       int tx_limit, rx_limit;
        u32 addr = msgs[dev->msg_write_idx].addr;
        u32 buf_len = dev->tx_buf_len;
        u8 *buf = dev->tx_buf;;
@@ -386,6 +385,9 @@ i2c_dw_xfer_msg(struct dw_i2c_dev *dev)
                        buf_len = msgs[dev->msg_write_idx].len;
                }

+               tx_limit = dev->tx_fifo_depth - readl(dev->base + DW_IC_TXFLR);
+               rx_limit = dev->rx_fifo_depth - readl(dev->base + DW_IC_RXFLR);
+
                while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) {
                        if (msgs[dev->msg_write_idx].flags & I2C_M_RD) {
                                writel(0x100, dev->base + DW_IC_DATA_CMD);
@@ -418,7 +420,7 @@ i2c_dw_read(struct dw_i2c_dev *dev)
{
        struct i2c_msg *msgs = dev->msgs;
        u32 addr = msgs[dev->msg_read_idx].addr;
-       int rx_valid = readl(dev->base + DW_IC_RXFLR);
+       int rx_valid;

        for (; dev->msg_read_idx < dev->msgs_num; dev->msg_read_idx++) {
                u32 len;
@@ -439,6 +441,8 @@ i2c_dw_read(struct dw_i2c_dev *dev)
                        buf = dev->rx_buf;
                }

+               rx_valid = readl(dev->base + DW_IC_RXFLR);
+
                for (; len > 0 && rx_valid > 0; len--, rx_valid--)
                        *buf++ = readl(dev->base + DW_IC_DATA_CMD);

--
1.6.5


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