Hi Kaustabh, On Fri, Oct 17, 2025 at 08:54:08PM +0530, Kaustabh Chakraborty wrote: >The current implementation polls for the DWMCI_CMD register, for the >DWMCI_CMD_START bit to turn off, which indicates that the command has >been completed. The problem with this approach is that it doesn't >address the DWMCI_INTMSK_CDONE bit in the interrupt register, >DWMCI_RINTSTS. As a result, subsequent commands result in timeout errors.
This patch looks good to me, but I need a few more details to understand: Do you mean that DWMCI_INTMSK_CDONE must be cleared before sending out next cmd? Per my guess, DWMCI_CMD_START will be cleared when CMD done from controller perspective, but the card may not return back response. DWMCI_INTMSK_CDONE means response done. But if there is some commands does not have response, will DWMCI_INTMSK_CDONE still be set? Please help clarify. Thanks, Peng > >Re-implement the waiting logic by polling for said interrupt status bit >and setting it low if raised. > >Signed-off-by: Kaustabh Chakraborty <[email protected]> >--- > drivers/mmc/dw_mmc.c | 17 +++++++++-------- > 1 file changed, 9 insertions(+), 8 deletions(-) > >diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c >index >130a5bb57f3cddc50b3cd0df2f40981de680e852..1aa992c352c3f11ccdd1c02745fa988646952261 > 100644 >--- a/drivers/mmc/dw_mmc.c >+++ b/drivers/mmc/dw_mmc.c >@@ -507,20 +507,21 @@ static int dwmci_control_clken(struct dwmci_host *host, >bool on) > { > const u32 val = on ? DWMCI_CLKEN_ENABLE | DWMCI_CLKEN_LOW_PWR : 0; > const u32 cmd_only_clk = DWMCI_CMD_PRV_DAT_WAIT | DWMCI_CMD_UPD_CLK; >- int timeout = 10000; >- u32 status; >+ int i, timeout = 10000; >+ u32 mask; > > dwmci_writel(host, DWMCI_CLKENA, val); > > /* Inform CIU */ > dwmci_writel(host, DWMCI_CMD, DWMCI_CMD_START | cmd_only_clk); >- do { >- status = dwmci_readl(host, DWMCI_CMD); >- if (timeout-- < 0) { >- debug("%s: Timeout!\n", __func__); >- return -ETIMEDOUT; >+ >+ for (i = 0; i < timeout; i++) { >+ mask = dwmci_readl(host, DWMCI_RINTSTS); >+ if (mask & DWMCI_INTMSK_CDONE) { >+ dwmci_writel(host, DWMCI_RINTSTS, DWMCI_INTMSK_CDONE); >+ break; > } >- } while (status & DWMCI_CMD_START); >+ } > > return 0; > } > >-- >2.51.0 >
