1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * MSDI IP block reset 4 * 5 * Copyright (C) 2012 Texas Instruments, Inc. 6 * Paul Walmsley 7 * 8 * XXX What about pad muxing? 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/err.h> 13 14 #include "prm.h" 15 #include "common.h" 16 #include "control.h" 17 #include "omap_hwmod.h" 18 #include "omap_device.h" 19 #include "mmc.h" 20 21 /* 22 * MSDI_CON_OFFSET: offset in bytes of the MSDI IP block's CON register 23 * from the IP block's base address 24 */ 25 #define MSDI_CON_OFFSET 0x0c 26 27 /* Register bitfields in the CON register */ 28 #define MSDI_CON_POW_MASK BIT(11) 29 #define MSDI_CON_CLKD_MASK (0x3f << 0) 30 #define MSDI_CON_CLKD_SHIFT 0 31 32 /* MSDI_TARGET_RESET_CLKD: clock divisor to use throughout the reset */ 33 #define MSDI_TARGET_RESET_CLKD 0x3ff 34 35 /** 36 * omap_msdi_reset - reset the MSDI IP block 37 * @oh: struct omap_hwmod * 38 * 39 * The MSDI IP block on OMAP2420 has to have both the POW and CLKD 40 * fields set inside its CON register for a reset to complete 41 * successfully. This is not documented in the TRM. For CLKD, we use 42 * the value that results in the lowest possible clock rate, to attempt 43 * to avoid disturbing any cards. 44 */ 45 int omap_msdi_reset(struct omap_hwmod *oh) 46 { 47 u16 v = 0; 48 int c = 0; 49 50 /* Write to the SOFTRESET bit */ 51 omap_hwmod_softreset(oh); 52 53 /* Enable the MSDI core and internal clock */ 54 v |= MSDI_CON_POW_MASK; 55 v |= MSDI_TARGET_RESET_CLKD << MSDI_CON_CLKD_SHIFT; 56 omap_hwmod_write(v, oh, MSDI_CON_OFFSET); 57 58 /* Poll on RESETDONE bit */ 59 omap_test_timeout((omap_hwmod_read(oh, oh->class->sysc->syss_offs) 60 & SYSS_RESETDONE_MASK), 61 MAX_MODULE_SOFTRESET_WAIT, c); 62 63 if (c == MAX_MODULE_SOFTRESET_WAIT) 64 pr_warn("%s: %s: softreset failed (waited %d usec)\n", 65 __func__, oh->name, MAX_MODULE_SOFTRESET_WAIT); 66 else 67 pr_debug("%s: %s: softreset in %d usec\n", __func__, 68 oh->name, c); 69 70 /* Disable the MSDI internal clock */ 71 v &= ~MSDI_CON_CLKD_MASK; 72 omap_hwmod_write(v, oh, MSDI_CON_OFFSET); 73 74 return 0; 75 } 76