mmc: sdhci-pci-dwc-mshc: synopsys dwc mshc support

Synopsys has DWC MSHC controller on HPAS-DX platform connected using PCIe
interface with SD card slot and eMMC device slots. This patch is to
enable SD cards connected on this platform. As Clock generation logic
is implemented using MMCM module of HAPS-DX platform, we have separate
functions to control the MMCM to generate required clocks with respect
to speed mode.

Signed-off-by: Prabu Thangamuthu <[e-mail]>
Acked-by: Adrian Hunter <[e-mail]>
Signed-off-by: Ulf Hansson <[e-mail]>

MAINTAINERS

···
 F:	drivers/mmc/host/sdhci*
 F:	include/linux/mmc/sdhci*
 
+SYNOPSYS SDHCI COMPLIANT DWC MSHC DRIVER
+M:	Prabu Thangamuthu <[e-mail]>
+M:	Manjunath M B <[e-mail]>
+L:	[e-mail]
+S:	Maintained
+F:	drivers/mmc/host/sdhci-pci-dwc-mshc.c
+
 SECURE DIGITAL HOST CONTROLLER INTERFACE (SDHCI) SAMSUNG DRIVER
 M:	Ben Dooks <[e-mail]>
 M:	Jaehoon Chung <[e-mail]>

drivers/mmc/host/Makefile

···
 obj-$(CONFIG_MMC_MXS)		+= mxs-mmc.o
 obj-$(CONFIG_MMC_SDHCI)		+= sdhci.o
 obj-$(CONFIG_MMC_SDHCI_PCI)	+= sdhci-pci.o
-sdhci-pci-y			+= sdhci-pci-core.o sdhci-pci-o2micro.o sdhci-pci-arasan.o
+sdhci-pci-y			+= sdhci-pci-core.o sdhci-pci-o2micro.o sdhci-pci-arasan.o \
+				   sdhci-pci-dwc-mshc.o
 obj-$(subst m,y,$(CONFIG_MMC_SDHCI_PCI))	+= sdhci-pci-data.o
 obj-$(CONFIG_MMC_SDHCI_ACPI)	+= sdhci-acpi.o
 obj-$(CONFIG_MMC_SDHCI_PXAV3)	+= sdhci-pxav3.o

drivers/mmc/host/sdhci-pci-core.c

···
 	SDHCI_PCI_DEVICE(O2, SEABIRD0, o2),
 	SDHCI_PCI_DEVICE(O2, SEABIRD1, o2),
 	SDHCI_PCI_DEVICE(ARASAN, PHY_EMMC, arasan),
+	SDHCI_PCI_DEVICE(SYNOPSYS, DWC_MSHC, snps),
 	SDHCI_PCI_DEVICE_CLASS(AMD, SYSTEM_SDHCI, PCI_CLASS_MASK, amd),
 	/* Generic SD host controller */
 	{PCI_DEVICE_CLASS(SYSTEM_SDHCI, PCI_CLASS_MASK)},

drivers/mmc/host/sdhci-pci-dwc-mshc.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SDHCI driver for Synopsys DWC_MSHC controller
+ *
+ * Copyright (C) 2018 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Authors:
+ *	Prabu Thangamuthu <[e-mail]>
+ *	Manjunath M B <[e-mail]>
+ */
+
+#include "sdhci.h"
+#include "sdhci-pci.h"
+
+#define SDHCI_VENDOR_PTR_R	0xE8
+
+/* Synopsys vendor specific registers */
+#define SDHC_GPIO_OUT		0x34
+#define SDHC_AT_CTRL_R		0x40
+#define SDHC_SW_TUNE_EN		0x00000010
+
+/* MMCM DRP */
+#define SDHC_MMCM_DIV_REG	0x1020
+#define DIV_REG_100_MHZ		0x1145
+#define DIV_REG_200_MHZ		0x1083
+#define SDHC_MMCM_CLKFBOUT	0x1024
+#define CLKFBOUT_100_MHZ	0x0000
+#define CLKFBOUT_200_MHZ	0x0080
+#define SDHC_CCLK_MMCM_RST	0x00000001
+
+static void sdhci_snps_set_clock(struct sdhci_host *host, unsigned int clock)
+{
+	u16 clk;
+	u32 reg, vendor_ptr;
+
+	vendor_ptr = sdhci_readw(host, SDHCI_VENDOR_PTR_R);
+
+	/* Disable software managed rx tuning */
+	reg = sdhci_readl(host, (SDHC_AT_CTRL_R + vendor_ptr));
+	reg &= ~SDHC_SW_TUNE_EN;
+	sdhci_writel(host, reg, (SDHC_AT_CTRL_R + vendor_ptr));
+
+	if (clock <= 52000000) {
+		sdhci_set_clock(host, clock);
+	} else {
+		/* Assert reset to MMCM */
+		reg = sdhci_readl(host, (SDHC_GPIO_OUT + vendor_ptr));
+		reg |= SDHC_CCLK_MMCM_RST;
+		sdhci_writel(host, reg, (SDHC_GPIO_OUT + vendor_ptr));
+
+		/* Configure MMCM */
+		if (clock == 100000000) {
+			sdhci_writel(host, DIV_REG_100_MHZ, SDHC_MMCM_DIV_REG);
+			sdhci_writel(host, CLKFBOUT_100_MHZ,
+					SDHC_MMCM_CLKFBOUT);
+		} else {
+			sdhci_writel(host, DIV_REG_200_MHZ, SDHC_MMCM_DIV_REG);
+			sdhci_writel(host, CLKFBOUT_200_MHZ,
+					SDHC_MMCM_CLKFBOUT);
+		}
+
+		/* De-assert reset to MMCM */
+		reg = sdhci_readl(host, (SDHC_GPIO_OUT + vendor_ptr));
+		reg &= ~SDHC_CCLK_MMCM_RST;
+		sdhci_writel(host, reg, (SDHC_GPIO_OUT + vendor_ptr));
+
+		/* Enable clock */
+		clk = SDHCI_PROG_CLOCK_MODE | SDHCI_CLOCK_INT_EN |
+			SDHCI_CLOCK_CARD_EN;
+		sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
+	}
+}
+
+static const struct sdhci_ops sdhci_snps_ops = {
+	.set_clock	= sdhci_snps_set_clock,
+	.enable_dma	= sdhci_pci_enable_dma,
+	.set_bus_width	= sdhci_set_bus_width,
+	.reset		= sdhci_reset,
+	.set_uhs_signaling = sdhci_set_uhs_signaling,
+};
+
+const struct sdhci_pci_fixes sdhci_snps = {
+	.ops		= &sdhci_snps_ops,
+};

drivers/mmc/host/sdhci-pci.h

···
 #define PCI_VENDOR_ID_ARASAN		0x16e6
 #define PCI_DEVICE_ID_ARASAN_PHY_EMMC	0x0670
 
+#define PCI_DEVICE_ID_SYNOPSYS_DWC_MSHC 0xc202
+
 /*
  * PCI device class and mask
  */
···
 #endif
 
 extern const struct sdhci_pci_fixes sdhci_arasan;
+extern const struct sdhci_pci_fixes sdhci_snps;
 
 #endif /* __SDHCI_PCI_H */