Thread (4 messages) 4 messages, 2 authors, 2021-12-21
STALE1664d LANDED: 3 (3M)
Revisions (2)
  1. v1 [diff vs current]
  2. v3 current

[PATCH v3 2/2] mmc: sdhci-pci-gli: GL975[50]: Issue 8/16-bit MMIO reads as 32-bit reads.

From: Hector Martin <hidden>
Date: 2021-12-15 16:16:47
Also in: linux-mmc, lkml
Subsystem: multimedia card (mmc), secure digital (sd) and sdio subsystem, secure digital host controller interface (sdhci) driver, the rest · Maintainers: Ulf Hansson, Adrian Hunter, Linus Torvalds

For some reason, <32-bit reads do not work on Apple ARM64 platforms with
these chips (even though they do on other PCIe devices). Issue them as
32-bit reads instead. This is done unconditionally, as it shouldn't hurt
even if not necessary.

Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Hector Martin <redacted>
---
 drivers/mmc/host/sdhci-pci-gli.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
index ad50f16658fe..97035d77c18c 100644
--- a/drivers/mmc/host/sdhci-pci-gli.c
+++ b/drivers/mmc/host/sdhci-pci-gli.c
@@ -902,7 +902,28 @@ static int gli_probe_slot_gl9763e(struct sdhci_pci_slot *slot)
 	return 0;
 }
 
+#define REG_OFFSET_IN_BITS(reg) ((reg) << 3 & 0x18)
+
+static u16 sdhci_gli_readw(struct sdhci_host *host, int reg)
+{
+	u32 val = readl(host->ioaddr + (reg & ~3));
+	u16 word;
+
+	word = (val >> REG_OFFSET_IN_BITS(reg)) & 0xffff;
+	return word;
+}
+
+static u8 sdhci_gli_readb(struct sdhci_host *host, int reg)
+{
+	u32 val = readl(host->ioaddr + (reg & ~3));
+	u8 byte = (val >> REG_OFFSET_IN_BITS(reg)) & 0xff;
+
+	return byte;
+}
+
 static const struct sdhci_ops sdhci_gl9755_ops = {
+	.read_w			= sdhci_gli_readw,
+	.read_b			= sdhci_gli_readb,
 	.set_clock		= sdhci_gl9755_set_clock,
 	.enable_dma		= sdhci_pci_enable_dma,
 	.set_bus_width		= sdhci_set_bus_width,
@@ -922,6 +943,8 @@ const struct sdhci_pci_fixes sdhci_gl9755 = {
 };
 
 static const struct sdhci_ops sdhci_gl9750_ops = {
+	.read_w			= sdhci_gli_readw,
+	.read_b			= sdhci_gli_readb,
 	.read_l                 = sdhci_gl9750_readl,
 	.set_clock		= sdhci_gl9750_set_clock,
 	.enable_dma		= sdhci_pci_enable_dma,
-- 
2.33.0


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