mmc: tegra: add basic Tegra186 support

Tegra186's MMC controller needs to be explicitly identified. Add another
compatible value for it.

Tegra186 will use an entirely different clock/reset control mechanism to
existing chips, and will use standard clock/reset APIs rather than the
existing Tegra-specific custom APIs. The driver support for that isn't
ready yet, so simply disable all clock/reset usage if compiling for
Tegra186. This must happen at compile time rather than run-time since the
custom APIs won't even be compiled in on Tegra186. In the long term, the
plan would be to convert the existing custom APIs to standard APIs and get
rid of the ifdefs completely.

The system's main eMMC will work without any clock/reset support, since
the firmware will have already initialized the controller in order to
load U-Boot. Hence the driver is useful even in this apparently crippled
state.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/drivers/mmc/tegra_mmc.c b/drivers/mmc/tegra_mmc.c
index 573819a..c9d9432 100644
--- a/drivers/mmc/tegra_mmc.c
+++ b/drivers/mmc/tegra_mmc.c
@@ -11,8 +11,10 @@
 #include <common.h>
 #include <asm/gpio.h>
 #include <asm/io.h>
+#ifndef CONFIG_TEGRA186
 #include <asm/arch/clock.h>
 #include <asm/arch-tegra/clk_rst.h>
+#endif
 #include <asm/arch-tegra/mmc.h>
 #include <asm/arch-tegra/tegra_mmc.h>
 #include <mmc.h>
@@ -357,8 +359,12 @@
 	 */
 	if (clock == 0)
 		goto out;
+#ifndef CONFIG_TEGRA186
 	clock_adjust_periph_pll_div(host->mmc_id, CLOCK_ID_PERIPH, clock,
 				    &div);
+#else
+	div = (20000000 + clock - 1) / clock;
+#endif
 	debug("div = %d\n", div);
 
 	writew(0, &host->reg->clkcon);
@@ -543,7 +549,9 @@
 	      gpio_get_number(&host->cd_gpio));
 
 	host->clock = 0;
+#ifndef CONFIG_TEGRA186
 	clock_start_periph_pll(host->mmc_id, CLOCK_ID_PERIPH, 20000000);
+#endif
 
 	if (dm_gpio_is_valid(&host->pwr_gpio))
 		dm_gpio_set_value(&host->pwr_gpio, 1);
@@ -568,7 +576,11 @@
 	 *  (actually 52MHz)
 	 */
 	host->cfg.f_min = 375000;
+#ifndef CONFIG_TEGRA186
 	host->cfg.f_max = 48000000;
+#else
+	host->cfg.f_max = 375000;
+#endif
 
 	host->cfg.b_max = CONFIG_SYS_MMC_MAX_BLK_COUNT;
 
@@ -600,11 +612,13 @@
 		return -FDT_ERR_NOTFOUND;
 	}
 
+#ifndef CONFIG_TEGRA186
 	host->mmc_id = clock_decode_periph_id(blob, node);
 	if (host->mmc_id == PERIPH_ID_NONE) {
 		debug("%s: could not decode periph id\n", __func__);
 		return -FDT_ERR_NOTFOUND;
 	}
+#endif
 
 	/*
 	 * NOTE: mmc->bus_width is determined by mmc.c dynamically.
@@ -624,7 +638,13 @@
 	*removablep = !fdtdec_get_bool(blob, node, "non-removable");
 
 	debug("%s: found controller at %p, width = %d, periph_id = %d\n",
-		__func__, host->reg, host->width, host->mmc_id);
+		__func__, host->reg, host->width,
+#ifndef CONFIG_TEGRA186
+		host->mmc_id
+#else
+		-1
+#endif
+	);
 	return 0;
 }
 
@@ -668,6 +688,16 @@
 	const void *blob = gd->fdt_blob;
 	debug("%s entry\n", __func__);
 
+	/* See if any Tegra186 MMC controllers are present */
+	count = fdtdec_find_aliases_for_id(blob, "sdhci",
+		COMPAT_NVIDIA_TEGRA186_SDMMC, node_list,
+		CONFIG_SYS_MMC_MAX_DEVICE);
+	debug("%s: count of Tegra186 sdhci nodes is %d\n", __func__, count);
+	if (process_nodes(blob, node_list, count)) {
+		printf("%s: Error processing T186 mmc node(s)!\n", __func__);
+		return;
+	}
+
 	/* See if any Tegra210 MMC controllers are present */
 	count = fdtdec_find_aliases_for_id(blob, "sdhci",
 		COMPAT_NVIDIA_TEGRA210_SDMMC, node_list,