1 /* 2 * MSDI IP block reset 3 * 4 * Copyright (C) 2012 Texas Instruments, Inc. 5 * Paul Walmsley 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * version 2 as published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, but 12 * WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 19 * 02110-1301 USA 20 * 21 * XXX What about pad muxing? 22 */ 23 24 #include <linux/kernel.h> 25 #include <linux/err.h> 26 #include <linux/platform_data/gpio-omap.h> 27 28 #include "prm.h" 29 #include "common.h" 30 #include "control.h" 31 #include "omap_hwmod.h" 32 #include "omap_device.h" 33 #include "mux.h" 34 #include "mmc.h" 35 36 /* 37 * MSDI_CON_OFFSET: offset in bytes of the MSDI IP block's CON register 38 * from the IP block's base address 39 */ 40 #define MSDI_CON_OFFSET 0x0c 41 42 /* Register bitfields in the CON register */ 43 #define MSDI_CON_POW_MASK BIT(11) 44 #define MSDI_CON_CLKD_MASK (0x3f << 0) 45 #define MSDI_CON_CLKD_SHIFT 0 46 47 /* MSDI_TARGET_RESET_CLKD: clock divisor to use throughout the reset */ 48 #define MSDI_TARGET_RESET_CLKD 0x3ff 49 50 /** 51 * omap_msdi_reset - reset the MSDI IP block 52 * @oh: struct omap_hwmod * 53 * 54 * The MSDI IP block on OMAP2420 has to have both the POW and CLKD 55 * fields set inside its CON register for a reset to complete 56 * successfully. This is not documented in the TRM. For CLKD, we use 57 * the value that results in the lowest possible clock rate, to attempt 58 * to avoid disturbing any cards. 59 */ 60 int omap_msdi_reset(struct omap_hwmod *oh) 61 { 62 u16 v = 0; 63 int c = 0; 64 65 /* Write to the SOFTRESET bit */ 66 omap_hwmod_softreset(oh); 67 68 /* Enable the MSDI core and internal clock */ 69 v |= MSDI_CON_POW_MASK; 70 v |= MSDI_TARGET_RESET_CLKD << MSDI_CON_CLKD_SHIFT; 71 omap_hwmod_write(v, oh, MSDI_CON_OFFSET); 72 73 /* Poll on RESETDONE bit */ 74 omap_test_timeout((omap_hwmod_read(oh, oh->class->sysc->syss_offs) 75 & SYSS_RESETDONE_MASK), 76 MAX_MODULE_SOFTRESET_WAIT, c); 77 78 if (c == MAX_MODULE_SOFTRESET_WAIT) 79 pr_warn("%s: %s: softreset failed (waited %d usec)\n", 80 __func__, oh->name, MAX_MODULE_SOFTRESET_WAIT); 81 else 82 pr_debug("%s: %s: softreset in %d usec\n", __func__, 83 oh->name, c); 84 85 /* Disable the MSDI internal clock */ 86 v &= ~MSDI_CON_CLKD_MASK; 87 omap_hwmod_write(v, oh, MSDI_CON_OFFSET); 88 89 return 0; 90 } 91