[PATCH] mmc: mediatek: Add cmd polling mode

[Derong Liu]

We found sdcard can gain more read/write performance
when using cmd polling mode instead of interrupt mode, in the meantime,
there are much more devices have equipped with high frequency cpu,
so it is necessary to support cmd polling mode.

Signed-off-by: Derong Liu <derong.liu@xxxxxxxxxxxx>
---
 drivers/mmc/host/mtk-sd.c | 92 +++++++++++++++++++++++++++++++++++----
 1 file changed, 83 insertions(+), 9 deletions(-)

diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
index 65037e1d7723..612f5115ca4b 100644
--- a/drivers/mmc/host/mtk-sd.c
+++ b/drivers/mmc/host/mtk-sd.c
@@ -465,6 +465,7 @@ struct msdc_host {
 	bool hs400_tuning;	/* hs400 mode online tuning */
 	bool internal_cd;	/* Use internal card-detect logic */
 	bool cqhci;		/* support eMMC hw cmdq */
+	bool cmd_polling_mode;	/* support cmd polling mode */
 	struct msdc_save_para save_para; /* used when gate HCLK */
 	struct msdc_tune_para def_tune_para; /* default tune setting */
 	struct msdc_tune_para saved_tune_para; /* tune result of CMD21/CMD19 */
@@ -1250,6 +1251,63 @@ static inline bool msdc_cmd_is_ready(struct msdc_host *host,
 	return true;
 }
 
+static inline int use_cmd_polling_mode(struct msdc_host *host,
+	struct mmc_command *cmd)
+{
+	/* R1B use interrupt mode */
+	return (host->cmd_polling_mode &&
+			((mmc_from_priv(host))->caps2 & MMC_CAP2_NO_SDIO) &&
+			(mmc_resp_type(cmd) != MMC_RSP_R1B));
+}
+
+static bool msdc_command_resp_polling(struct msdc_host *host,
+	struct mmc_request *mrq, struct mmc_command *cmd,
+	unsigned long timeout)
+{
+	bool ret = false;
+	unsigned long tmo;
+	int events;
+	unsigned long flags;
+
+	if (!use_cmd_polling_mode(host, cmd))
+		goto exit;
+
+retry:
+	tmo = jiffies + timeout;
+	while (1) {
+		spin_lock_irqsave(&host->lock, flags);
+		events = readl(host->base + MSDC_INT);
+		if (events & cmd_ints_mask) {
+			/* clear all int flag */
+			events &= cmd_ints_mask;
+			writel(events, host->base + MSDC_INT);
+			spin_unlock_irqrestore(&host->lock, flags);
+			break;
+		}
+		spin_unlock_irqrestore(&host->lock, flags);
+
+		if (time_after(jiffies, tmo) &&
+			((events & cmd_ints_mask) == 0)) {
+			dev_info(host->dev, "[%s]: CMD<%d> polling_for_completion timeout ARG<0x%.8x>\n",
+				__func__, cmd->opcode, cmd->arg);
+			ret = msdc_cmd_done(host, MSDC_INT_CMDTMO, mrq, cmd);
+			goto exit;
+		}
+	}
+
+	if (cmd) {
+		ret = msdc_cmd_done(host, events, mrq, cmd);
+		/* if only autocmd23 done,
+		 * it needs to polling the continue read/write cmd directly.
+		 */
+		if (!ret)
+			goto retry;
+	}
+
+exit:
+	return ret;
+}
+
 static void msdc_start_command(struct msdc_host *host,
 		struct mmc_request *mrq, struct mmc_command *cmd)
 {
@@ -1273,7 +1331,10 @@ static void msdc_start_command(struct msdc_host *host,
 	rawcmd = msdc_cmd_prepare_raw_cmd(host, mrq, cmd);
 
 	spin_lock_irqsave(&host->lock, flags);
-	sdr_set_bits(host->base + MSDC_INTEN, cmd_ints_mask);
+	if (use_cmd_polling_mode(host, cmd))
+		sdr_clr_bits(host->base + MSDC_INTEN, cmd_ints_mask);
+	else
+		sdr_set_bits(host->base + MSDC_INTEN, cmd_ints_mask);
 	spin_unlock_irqrestore(&host->lock, flags);
 
 	writel(cmd->arg, host->base + SDC_ARG);
@@ -1290,9 +1351,11 @@ static void msdc_cmd_next(struct msdc_host *host,
 	       host->hs400_tuning))) ||
 	    (mrq->sbc && mrq->sbc->error))
 		msdc_request_done(host, mrq);
-	else if (cmd == mrq->sbc)
+	else if (cmd == mrq->sbc) {
 		msdc_start_command(host, mrq, mrq->cmd);
-	else if (!cmd->data)
+		msdc_command_resp_polling(host, mrq,
+				mrq->cmd, CMD_TIMEOUT);
+	} else if (!cmd->data)
 		msdc_request_done(host, mrq);
 	else
 		msdc_start_data(host, cmd, cmd->data);
@@ -1314,10 +1377,15 @@ static void msdc_ops_request(struct mmc_host *mmc, struct mmc_request *mrq)
 	 * use HW option,  otherwise use SW option
 	 */
 	if (mrq->sbc && (!mmc_card_mmc(mmc->card) ||
-	    (mrq->sbc->arg & 0xFFFF0000)))
+	    (mrq->sbc->arg & 0xFFFF0000))) {
 		msdc_start_command(host, mrq, mrq->sbc);
-	else
+		msdc_command_resp_polling(host, mrq,
+				mrq->sbc, CMD_TIMEOUT);
+	} else {
 		msdc_start_command(host, mrq, mrq->cmd);
+		msdc_command_resp_polling(host, mrq,
+				mrq->cmd, CMD_TIMEOUT);
+	}
 }
 
 static void msdc_pre_req(struct mmc_host *mmc, struct mmc_request *mrq)
@@ -1350,9 +1418,11 @@ static void msdc_post_req(struct mmc_host *mmc, struct mmc_request *mrq,
 static void msdc_data_xfer_next(struct msdc_host *host, struct mmc_request *mrq)
 {
 	if (mmc_op_multi(mrq->cmd->opcode) && mrq->stop && !mrq->stop->error &&
-	    !mrq->sbc)
+	    !mrq->sbc) {
 		msdc_start_command(host, mrq, mrq->stop);
-	else
+		msdc_command_resp_polling(host, mrq,
+				mrq->stop, CMD_TIMEOUT);
+	} else
 		msdc_request_done(host, mrq);
 }
 
@@ -2492,11 +2562,15 @@ static void msdc_of_property_parse(struct platform_device *pdev,
 	else
 		host->hs400_cmd_resp_sel_rising = false;
 
-	if (of_property_read_bool(pdev->dev.of_node,
-				  "supports-cqe"))
+	if (of_property_read_bool(pdev->dev.of_node, "supports-cqe"))
 		host->cqhci = true;
 	else
 		host->cqhci = false;
+
+	if (of_property_read_bool(pdev->dev.of_node, "mediatek,cmd-polling-mode"))
+		host->cmd_polling_mode = true;
+	else
+		host->cmd_polling_mode = false;
 }
 
 static int msdc_of_clock_parse(struct platform_device *pdev,
-- 
2.18.0