Commit e809517f authored by Pierre Ossman's avatar Pierre Ossman
Browse files

sdhci: let the controller wait for busy state to end 



The sdhci controllers can interrupt us when the busy state from the
card has ended, saving CPU cycles and power.

Signed-off-by: default avatarPierre Ossman <drzeus@drzeus.cx>
parent 3fa8749e

drivers/mmc/host/sdhci.c

+33 −6
Original line number Diff line number Diff line
@@ -1266,9 +1266,31 @@ static void sdhci_cmd_irq(struct sdhci_host *host, u32 intmask) 
			SDHCI_INT_INDEX))

		host->cmd->error = -EILSEQ;



	if (host->cmd->error)

	if (host->cmd->error) {

		tasklet_schedule(&host->finish_tasklet);

	else if (intmask & SDHCI_INT_RESPONSE)

		return;

	}



	/*

	 * The host can send and interrupt when the busy state has

	 * ended, allowing us to wait without wasting CPU cycles.

	 * Unfortunately this is overloaded on the "data complete"

	 * interrupt, so we need to take some care when handling

	 * it.

	 *

	 * Note: The 1.0 specification is a bit ambiguous about this

	 *       feature so there might be some problems with older

	 *       controllers.

	 */

	if (host->cmd->flags & MMC_RSP_BUSY) {

		if (host->cmd->data)

			DBG("Cannot wait for busy signal when also "

				"doing a data transfer");

		else

			return;

	}



	if (intmask & SDHCI_INT_RESPONSE)

		sdhci_finish_command(host);

}
@@ -1278,11 +1300,16 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask) 


	if (!host->data) {

		/*

		 * A data end interrupt is sent together with the response

		 * for the stop command.

		 * The "data complete" interrupt is also used to

		 * indicate that a busy state has ended. See comment

		 * above in sdhci_cmd_irq().

		 */

		if (intmask & SDHCI_INT_DATA_END)

		if (host->cmd && (host->cmd->flags & MMC_RSP_BUSY)) {

			if (intmask & SDHCI_INT_DATA_END) {

				sdhci_finish_command(host);

				return;

			}

		}



		printk(KERN_ERR "%s: Got data interrupt 0x%08x even "

			"though no data operation was in progress.\n",