netdev - RE: [PATCH net-next v2 01/16] net: txgbe: Store PCI info

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Message-ID: <025701d8bce0$36fc7300$a4f55900$@trustnetic.com>
Date:   Wed, 31 Aug 2022 10:20:18 +0800
From:   Jiawen Wu <jiawenwu@...stnetic.com>
To:     "'Andrew Lunn'" <andrew@...n.ch>
Cc:     <netdev@...r.kernel.org>, <mengyuanlou@...-swift.com>
Subject: RE: [PATCH net-next v2 01/16] net: txgbe: Store PCI info

On Wednesday, August 31, 2022 8:07 AM, Andrew Lunn wrote:
> > +/* cmd_addr is used for some special command:
> > + * 1. to be sector address, when implemented erase sector command
> > + * 2. to be flash address when implemented read, write flash address
> > +*/ int txgbe_fmgr_cmd_op(struct txgbe_hw *hw, u32 cmd, u32 cmd_addr)
> > +{
> > +	u32 cmd_val = 0, val = 0;
> > +
> > +	cmd_val = (cmd << SPI_CLK_CMD_OFFSET) |
> > +		  (SPI_CLK_DIV << SPI_CLK_DIV_OFFSET) | cmd_addr;
> > +	wr32(hw, SPI_H_CMD_REG_ADDR, cmd_val);
> > +
> > +	return read_poll_timeout(rd32, val, (val & 0x1), 10,
> SPI_TIME_OUT_VALUE,
> > +				 false, hw, SPI_H_STA_REG_ADDR);
> > +}
> > +
> 
> > +int txgbe_flash_read_dword(struct txgbe_hw *hw, u32 addr, u32 *data)
> > +{
> > +	int ret = 0;
> > +
> > +	ret = txgbe_fmgr_cmd_op(hw, SPI_CMD_READ_DWORD, addr);
> > +	if (ret == -ETIMEDOUT)
> > +		return ret;
> 
> Are you absolutely sure it will never return any other error code?
> The pattern in the kernel is
> 
> > +	if (ret)
> > +		return ret;
> 
> or
> 
> > +	if (ret < 0)
> > +		return ret;
> 

I found that the function 'read_poll_timeout()' only returns 0 or
-ETIMEDOUT.
But I'll fix it to be safe.

> > +int txgbe_check_flash_load(struct txgbe_hw *hw, u32 check_bit) {
> > +	u32 i = 0, reg = 0;
> > +	int err = 0;
> > +
> > +	/* if there's flash existing */
> > +	if (!(rd32(hw, TXGBE_SPI_STATUS) &
> > +	      TXGBE_SPI_STATUS_FLASH_BYPASS)) {
> > +		/* wait hw load flash done */
> > +		for (i = 0; i < TXGBE_MAX_FLASH_LOAD_POLL_TIME; i++) {
> > +			reg = rd32(hw, TXGBE_SPI_ILDR_STATUS);
> > +			if (!(reg & check_bit)) {
> > +				/* done */
> > +				break;
> > +			}
> > +			msleep(200);
> > +		}
> 
> This is what iopoll.h is for. Any sort of loop waiting for something to
happen
> should use one of the helpers in there.
> 

The description of functions in iopoll.h states that maximum sleep time
should be less than 20ms, is it okay to call it here for 200ms.