From 77780b2dd88b520c3768c5c3ff7213fe052f2e48 Mon Sep 17 00:00:00 2001
From: Shawn Lin <shawn.lin@rock-chips.com>
Date: Thu, 21 Mar 2019 09:45:31 +0800
Subject: [PATCH] mmc: core: Add mmc_sd_shutdown support for SD as main disk

The ROM code for Rockchip platform never support detecting
SD 3.0 mode, so if the SD card contains system image running
into SD 3.0 mode in kernel, it will fails to reboot.

The problem is SD 3.0 mode is using 1.8V signal and could only
be switched back into 2.0 mode by power cycle. If the customed
board could not switch off its power rail, the ROM code can't
soft reset the SD.

Add mmc_sd_shutdown to workaround this special case and don't
bother normal SD cards used as external disk by checking the
RESTRICT_CARD_TYPE_MMC flag.

Conflicts:
	drivers/mmc/core/sd.c

Change-Id: I4c3d3111c0bce0ad3cd4f0c6592ff595d7015afe
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
---
 drivers/mmc/core/sd.c | 54 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 53 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 04738359ec02..9bf527107aaf 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1150,6 +1150,58 @@ out:
 	return err;
 }
 
+static int _mmc_sd_shutdown(struct mmc_host *host)
+{
+	int err = 0;
+
+	BUG_ON(!host);
+	BUG_ON(!host->card);
+
+	mmc_claim_host(host);
+
+	if (mmc_card_suspended(host->card))
+		goto out;
+
+	if (!mmc_host_is_spi(host))
+		err = mmc_deselect_cards(host);
+
+	if (!err) {
+		mmc_power_off(host);
+		mmc_card_set_suspended(host->card);
+	}
+
+	/*
+	 * mmc_sd_shutdown is used for SD card, so what we need
+	 * is to make sure we set signal voltage to initial state
+	 * if it's used as main disk. RESTRICT_CARD_TYPE_MMC is
+	 * combined into host->restrict_caps via DT for SD cards
+	 * running system image.
+	 */
+	if (host->restrict_caps & RESTRICT_CARD_TYPE_EMMC) {
+		host->ios.signal_voltage = MMC_SIGNAL_VOLTAGE_330;
+		host->ios.vdd = fls(host->ocr_avail) - 1;
+		mmc_regulator_set_vqmmc(host, &host->ios);
+		pr_info("Set signal voltage to initial state\n");
+	}
+
+out:
+	mmc_release_host(host);
+	return err;
+}
+
+static int mmc_sd_shutdown(struct mmc_host *host)
+{
+	int err;
+
+	err = _mmc_sd_shutdown(host);
+	if (!err) {
+		pm_runtime_disable(&host->card->dev);
+		pm_runtime_set_suspended(&host->card->dev);
+	}
+
+	return err;
+}
+
 /*
  * Callback for suspend
  */
@@ -1244,7 +1296,7 @@ static const struct mmc_bus_ops mmc_sd_ops = {
 	.suspend = mmc_sd_suspend,
 	.resume = mmc_sd_resume,
 	.alive = mmc_sd_alive,
-	.shutdown = mmc_sd_suspend,
+	.shutdown = mmc_sd_shutdown,
 	.hw_reset = mmc_sd_hw_reset,
 };