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 27 #include "prm.h" 28 #include "common.h" 29 #include "control.h" 30 #include "omap_hwmod.h" 31 #include "omap_device.h" 32 #include "mmc.h" 33 34 /* 35 * MSDI_CON_OFFSET: offset in bytes of the MSDI IP block's CON register 36 * from the IP block's base address 37 */ 38 #define MSDI_CON_OFFSET 0x0c 39 40 /* Register bitfields in the CON register */ 41 #define MSDI_CON_POW_MASK BIT(11) 42 #define MSDI_CON_CLKD_MASK (0x3f << 0) 43 #define MSDI_CON_CLKD_SHIFT 0 44 45 /* MSDI_TARGET_RESET_CLKD: clock divisor to use throughout the reset */ 46 #define MSDI_TARGET_RESET_CLKD 0x3ff 47 48 /** 49 * omap_msdi_reset - reset the MSDI IP block 50 * @oh: struct omap_hwmod * 51 * 52 * The MSDI IP block on OMAP2420 has to have both the POW and CLKD 53 * fields set inside its CON register for a reset to complete 54 * successfully. This is not documented in the TRM. For CLKD, we use 55 * the value that results in the lowest possible clock rate, to attempt 56 * to avoid disturbing any cards. 57 */ 58 int omap_msdi_reset(struct omap_hwmod *oh) 59 { 60 u16 v = 0; 61 int c = 0; 62 63 /* Write to the SOFTRESET bit */ 64 omap_hwmod_softreset(oh); 65 66 /* Enable the MSDI core and internal clock */ 67 v |= MSDI_CON_POW_MASK; 68 v |= MSDI_TARGET_RESET_CLKD << MSDI_CON_CLKD_SHIFT; 69 omap_hwmod_write(v, oh, MSDI_CON_OFFSET); 70 71 /* Poll on RESETDONE bit */ 72 omap_test_timeout((omap_hwmod_read(oh, oh->class->sysc->syss_offs) 73 & SYSS_RESETDONE_MASK), 74 MAX_MODULE_SOFTRESET_WAIT, c); 75 76 if (c == MAX_MODULE_SOFTRESET_WAIT) 77 pr_warn("%s: %s: softreset failed (waited %d usec)\n", 78 __func__, oh->name, MAX_MODULE_SOFTRESET_WAIT); 79 else 80 pr_debug("%s: %s: softreset in %d usec\n", __func__, 81 oh->name, c); 82 83 /* Disable the MSDI internal clock */ 84 v &= ~MSDI_CON_CLKD_MASK; 85 omap_hwmod_write(v, oh, MSDI_CON_OFFSET); 86 87 return 0; 88 } 89