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-rw-r--r--arch/arm/mach-omap2/msdi.c88
1 files changed, 88 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/msdi.c b/arch/arm/mach-omap2/msdi.c
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+/*
+ * MSDI IP block reset
+ *
+ * Copyright (C) 2012 Texas Instruments, Inc.
+ * Paul Walmsley
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ * XXX What about pad muxing?
+ */
+
+#include <linux/kernel.h>
+
+#include <plat/omap_hwmod.h>
+#include <plat/mmc.h>
+
+#include "common.h"
+
+/*
+ * MSDI_CON_OFFSET: offset in bytes of the MSDI IP block's CON register
+ * from the IP block's base address
+ */
+#define MSDI_CON_OFFSET 0x0c
+
+/* Register bitfields in the CON register */
+#define MSDI_CON_POW_MASK BIT(11)
+#define MSDI_CON_CLKD_MASK (0x3f << 0)
+#define MSDI_CON_CLKD_SHIFT 0
+
+/* Maximum microseconds to wait for OMAP module to softreset */
+#define MAX_MODULE_SOFTRESET_WAIT 10000
+
+/* MSDI_TARGET_RESET_CLKD: clock divisor to use throughout the reset */
+#define MSDI_TARGET_RESET_CLKD 0x3ff
+
+/**
+ * omap_msdi_reset - reset the MSDI IP block
+ * @oh: struct omap_hwmod *
+ *
+ * The MSDI IP block on OMAP2420 has to have both the POW and CLKD
+ * fields set inside its CON register for a reset to complete
+ * successfully. This is not documented in the TRM. For CLKD, we use
+ * the value that results in the lowest possible clock rate, to attempt
+ * to avoid disturbing any cards.
+ */
+int omap_msdi_reset(struct omap_hwmod *oh)
+{
+ u16 v = 0;
+ int c = 0;
+
+ /* Write to the SOFTRESET bit */
+ omap_hwmod_softreset(oh);
+
+ /* Enable the MSDI core and internal clock */
+ v |= MSDI_CON_POW_MASK;
+ v |= MSDI_TARGET_RESET_CLKD << MSDI_CON_CLKD_SHIFT;
+ omap_hwmod_write(v, oh, MSDI_CON_OFFSET);
+
+ /* Poll on RESETDONE bit */
+ omap_test_timeout((omap_hwmod_read(oh, oh->class->sysc->syss_offs)
+ & SYSS_RESETDONE_MASK),
+ MAX_MODULE_SOFTRESET_WAIT, c);
+
+ if (c == MAX_MODULE_SOFTRESET_WAIT)
+ pr_warning("%s: %s: softreset failed (waited %d usec)\n",
+ __func__, oh->name, MAX_MODULE_SOFTRESET_WAIT);
+ else
+ pr_debug("%s: %s: softreset in %d usec\n", __func__,
+ oh->name, c);
+
+ /* Disable the MSDI internal clock */
+ v &= ~MSDI_CON_CLKD_MASK;
+ omap_hwmod_write(v, oh, MSDI_CON_OFFSET);
+
+ return 0;
+}