[PATCH v2 2/2] mmc: sdhci-pci-gli: GL975[50]: Issue 8/16-bit MMIO reads as 32-bit reads.

[Hector Martin <marcan@marcan.st>]

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.

Signed-off-by: Hector Martin <marcan@marcan.st>
---
 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 ad742743a494..c6828e84db31 100644
--- a/drivers/mmc/host/sdhci-pci-gli.c
+++ b/drivers/mmc/host/sdhci-pci-gli.c
@@ -906,7 +906,28 @@ 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,
@@ -926,6 +947,8 @@ 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