From 9bfeadf73f0f747b8c0d63bcd296bffa07f62755 Mon Sep 17 00:00:00 2001
From: Jonathan Bell <jonathan@raspberrypi.com>
Date: Thu, 13 Jun 2024 15:01:02 +0100
Subject: [PATCH] drivers: mmc: sdhci-brcmstb: improve bcm2712 card removal
 handling

If the controller is being reset, then the CQE needs to be reset as well.

For removable cards, CQHCI_SSC1 must specify a polling mode (CBC=0)
otherwise it's possible that the controller stops emitting periodic
CMD13s on card removal, without raising an error status interrupt.

Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
---
 drivers/mmc/host/sdhci-brcmstb.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

--- a/drivers/mmc/host/sdhci-brcmstb.c
+++ b/drivers/mmc/host/sdhci-brcmstb.c
@@ -412,8 +412,21 @@ static void sdhci_brcmstb_cqe_enable(str
 
 	sdhci_cqe_enable(mmc);
 
-	/* Reset CMD13 polling timer back to eMMC specification default */
-	cqhci_writel(cq_host, 0x00011000, CQHCI_SSC1);
+	/*
+	 * The controller resets this register to a very short default interval
+	 * whenever CQHCI is disabled.
+	 *
+	 * For removable cards CBC needs to be clear or card removal can hang
+	 * the CQE. In polling mode, a CIT of 0x4000 "cycles" seems to produce the best
+	 * throughput.
+	 *
+	 * For nonremovable cards, the specification default of CBC=1 CIT=0x1000
+	 * suffices.
+	 */
+	if (mmc->caps & MMC_CAP_NONREMOVABLE)
+		cqhci_writel(cq_host, 0x00011000, CQHCI_SSC1);
+	else
+		cqhci_writel(cq_host, 0x00004000, CQHCI_SSC1);
 }
 
 static const struct cqhci_host_ops sdhci_brcmstb_cqhci_ops = {
@@ -433,7 +446,7 @@ static struct sdhci_ops sdhci_brcmstb_op
 	.set_clock = sdhci_bcm2712_set_clock,
 	.set_power = sdhci_brcmstb_set_power,
 	.set_bus_width = sdhci_set_bus_width,
-	.reset = sdhci_reset,
+	.reset = brcmstb_reset,
 	.set_uhs_signaling = sdhci_set_uhs_signaling,
 	.init_sd_express = bcm2712_init_sd_express,
 };
