1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Au1300 media block power gating (VSS)
4 *
5 * This is a stop-gap solution until I have the clock framework integration
6 * ready. This stuff here really must be handled transparently when clocks
7 * for various media blocks are enabled/disabled.
8 */
9
10 #include <linux/export.h>
11 #include <linux/spinlock.h>
12 #include <asm/mach-au1x00/au1000.h>
13
14 #define VSS_GATE 0x00 /* gate wait timers */
15 #define VSS_CLKRST 0x04 /* clock/block control */
16 #define VSS_FTR 0x08 /* footers */
17
18 #define VSS_ADDR(blk) (KSEG1ADDR(AU1300_VSS_PHYS_ADDR) + (blk * 0x0c))
19
20 static DEFINE_SPINLOCK(au1300_vss_lock);
21
22 /* enable a block as outlined in the databook */
23 static inline void __enable_block(int block)
24 {
25 void __iomem *base = (void __iomem *)VSS_ADDR(block);
26
27 __raw_writel(3, base + VSS_CLKRST); /* enable clock, assert reset */
28 wmb();
29
30 __raw_writel(0x01fffffe, base + VSS_GATE); /* maximum setup time */
31 wmb();
32
33 /* enable footers in sequence */
34 __raw_writel(0x01, base + VSS_FTR);
35 wmb();
36 __raw_writel(0x03, base + VSS_FTR);
37 wmb();
38 __raw_writel(0x07, base + VSS_FTR);
39 wmb();
40 __raw_writel(0x0f, base + VSS_FTR);
41 wmb();
42
43 __raw_writel(0x01ffffff, base + VSS_GATE); /* start FSM too */
44 wmb();
45
46 __raw_writel(2, base + VSS_CLKRST); /* deassert reset */
47 wmb();
48
49 __raw_writel(0x1f, base + VSS_FTR); /* enable isolation cells */
50 wmb();
51 }
52
53 /* disable a block as outlined in the databook */
54 static inline void __disable_block(int block)
55 {
56 void __iomem *base = (void __iomem *)VSS_ADDR(block);
57
58 __raw_writel(0x0f, base + VSS_FTR); /* disable isolation cells */
59 wmb();
60 __raw_writel(0, base + VSS_GATE); /* disable FSM */
61 wmb();
62 __raw_writel(3, base + VSS_CLKRST); /* assert reset */
63 wmb();
64 __raw_writel(1, base + VSS_CLKRST); /* disable clock */
65 wmb();
66 __raw_writel(0, base + VSS_FTR); /* disable all footers */
67 wmb();
68 }
69
70 void au1300_vss_block_control(int block, int enable)
71 {
72 unsigned long flags;
73
74 if (alchemy_get_cputype() != ALCHEMY_CPU_AU1300)
75 return;
76
77 /* only one block at a time */
78 spin_lock_irqsave(&au1300_vss_lock, flags);
79 if (enable)
80 __enable_block(block);
81 else
82 __disable_block(block);
83 spin_unlock_irqrestore(&au1300_vss_lock, flags);
84 }
85 EXPORT_SYMBOL_GPL(au1300_vss_block_control);
86
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