提交 ae7304c3 编写于 作者: S Shubhrajyoti Datta 提交者: Wolfram Sang

i2c: xiic: Make the start and the byte count write atomic

Disable interrupts while configuring the transfer and enable them back.

We have below as the programming sequence
1. start and slave address
2. byte count and stop

In some customer platform there was a lot of interrupts between 1 and 2
and after slave address (around 7 clock cyles) if 2 is not executed
then the transaction is nacked.

To fix this case make the 2 writes atomic.
Signed-off-by: NShubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
[wsa: added a newline for better readability]
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
上级 851a1511
......@@ -532,6 +532,7 @@ static void xiic_start_recv(struct xiic_i2c *i2c)
{
u8 rx_watermark;
struct i2c_msg *msg = i2c->rx_msg = i2c->tx_msg;
unsigned long flags;
/* Clear and enable Rx full interrupt. */
xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK | XIIC_INTR_TX_ERROR_MASK);
......@@ -547,6 +548,7 @@ static void xiic_start_recv(struct xiic_i2c *i2c)
rx_watermark = IIC_RX_FIFO_DEPTH;
xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, rx_watermark - 1);
local_irq_save(flags);
if (!(msg->flags & I2C_M_NOSTART))
/* write the address */
xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET,
......@@ -556,6 +558,8 @@ static void xiic_start_recv(struct xiic_i2c *i2c)
xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET,
msg->len | ((i2c->nmsgs == 1) ? XIIC_TX_DYN_STOP_MASK : 0));
local_irq_restore(flags);
if (i2c->nmsgs == 1)
/* very last, enable bus not busy as well */
xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK);
......
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