On Thu, Nov 7, 2019 at 7:16 PM <yhchuang@xxxxxxxxxxx> wrote:
>
> From: Yan-Hsuan Chuang <yhchuang@xxxxxxxxxxx>
>
> By Realtek's design, there are two HW modules associated for CLKREQ,
> one is responsible to follow the PCIE host settings, and another
> is to actually working on it. But the module that is actually working
> on it is default disabled, and driver should enable that module if
> host and device have successfully sync'ed with each other.
>
> The module is default disabled because sometimes the host does not
> support it, and if there is any incorrect settings (ex. CLKREQ# is
> not Bi-Direction), device can be lost and disconnected to the host.
>
> So driver should first check after host and device are sync'ed, and
> the host does support the function and set it in configuration
> space, then driver can turn on the HW module to working on it.
>
> Signed-off-by: Yan-Hsuan Chuang <yhchuang@xxxxxxxxxxx>
> ---
> drivers/net/wireless/realtek/rtw88/pci.c | 83 ++++++++++++++++++++++++
> drivers/net/wireless/realtek/rtw88/pci.h | 5 ++
> 2 files changed, 88 insertions(+)
>
> diff --git a/drivers/net/wireless/realtek/rtw88/pci.c b/drivers/net/wireless/realtek/rtw88/pci.c
> index 6d1aa6f41e84..4fcef8a6fc42 100644
> --- a/drivers/net/wireless/realtek/rtw88/pci.c
> +++ b/drivers/net/wireless/realtek/rtw88/pci.c
> @@ -1081,6 +1081,33 @@ static void rtw_dbi_write8(struct rtw_dev *rtwdev, u16 addr, u8 data)
> WARN(flag, "failed to write to DBI register, addr=0x%04x\n", addr);
> }
>
> +static int rtw_dbi_read8(struct rtw_dev *rtwdev, u16 addr, u8 *value)
> +{
> + u16 read_addr = addr & BITS_DBI_ADDR_MASK;
> + u8 flag;
> + u8 cnt;
> +
> + rtw_write16(rtwdev, REG_DBI_FLAG_V1, read_addr);
> + rtw_write8(rtwdev, REG_DBI_FLAG_V1 + 2, BIT_DBI_RFLAG >> 16);
> +
> + for (cnt = 0; cnt < RTW_PCI_WR_RETRY_CNT; cnt++) {
> + flag = rtw_read8(rtwdev, REG_DBI_FLAG_V1 + 2);
> + if (flag == 0)
> + break;
Why not just doing ' rtw_read8(rtwdev, read_addr);' and return here?
Then you don't need to check the flag != 0 at the following. It would
make the code cleaner and same expressive.
> +
> + udelay(10);
> + }
> +
> + if (flag != 0) {
> + WARN(1, "failed to read DBI register, addr=0x%04x\n", addr);
> + return -EIO;
> + }
> +
> + read_addr = REG_DBI_RDATA_V1 + (addr & 3);
> + *value = rtw_read8(rtwdev, read_addr);
> + return 0;
> +}
> +
> --
> 2.17.1
>
