mmc: atmel: Add atmel sdhci support

The SDHCI is introduced by sama5d2, named as Secure Digital Multimedia
Card Controller(SDMMC). It supports the embedded MultiMedia Card (e.MMC)
Specification V4.41, the SD Memory Card Specification V3.0, and the SDIO
V3.0 specification. It is compliant with the SD Host Controller Standard
V3.0 specification.
Signed-off-by: NWenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: NAndreas Bießmann <andreas.devel@googlemail.com>

arch/arm/mach-at91/include/mach/atmel_sdhci.h

+/*
+ * Copyright (c) 2015 Atmel Corporation
+ *		      Wenyou.Yang <wenyou.yang@atmel.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __ATMEL_SDHCI_H
+#define __ATMEL_SDHCI_H
+
+int atmel_sdhci_init(void *regbase, u32 id);
+
+#endif

drivers/mmc/Makefile

@@ -8,6 +8,7 @@
 obj-$(CONFIG_DM_MMC) += mmc-uclass.o
 
 obj-$(CONFIG_ARM_PL180_MMCI) += arm_pl180_mmci.o
+obj-$(CONFIG_ATMEL_SDHCI) += atmel_sdhci.o
 obj-$(CONFIG_BCM2835_SDHCI) += bcm2835_sdhci.o
 obj-$(CONFIG_BFIN_SDH) += bfin_sdh.o
 obj-$(CONFIG_DAVINCI_MMC) += davinci_mmc.o

drivers/mmc/atmel_sdhci.c

+/*
+ * Copyright (C) 2015 Atmel Corporation
+ *		      Wenyou.Yang <wenyou.yang@atmel.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <sdhci.h>
+#include <asm/arch/clk.h>
+
+#define ATMEL_SDHC_MIN_FREQ	400000
+
+int atmel_sdhci_init(void *regbase, u32 id)
+{
+	struct sdhci_host *host;
+	u32 max_clk, min_clk = ATMEL_SDHC_MIN_FREQ;
+
+	host = (struct sdhci_host *)calloc(1, sizeof(struct sdhci_host));
+	if (!host) {
+		printf("%s: sdhci_host calloc failed\n", __func__);
+		return -ENOMEM;
+	}
+
+	host->name = "atmel_sdhci";
+	host->ioaddr = regbase;
+	host->quirks = 0;
+	host->version = sdhci_readw(host, SDHCI_HOST_VERSION);
+	max_clk = at91_get_periph_generated_clk(id);
+	if (!max_clk) {
+		printf("%s: Failed to get the proper clock\n", __func__);
+		free(host);
+		return -ENODEV;
+	}
+
+	add_sdhci(host, max_clk, min_clk);
+
+	return 0;
+}