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 | |