1 /*
2 * Driver for the Synopsys DesignWare AHB DMA Controller
3 *
4 * Copyright (C) 2005-2007 Atmel Corporation
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11 #include <linux/dw_dmac.h>
12
13 #define DW_DMA_MAX_NR_CHANNELS 8
14
15 /*
16 * Redefine this macro to handle differences between 32- and 64-bit
17 * addressing, big vs. little endian, etc.
18 */
19 #define DW_REG(name) u32 name; u32 __pad_##name
20
21 /* Hardware register definitions. */
22 struct dw_dma_chan_regs {
23 DW_REG(SAR); /* Source Address Register */
24 DW_REG(DAR); /* Destination Address Register */
25 DW_REG(LLP); /* Linked List Pointer */
26 u32 CTL_LO; /* Control Register Low */
27 u32 CTL_HI; /* Control Register High */
28 DW_REG(SSTAT);
29 DW_REG(DSTAT);
30 DW_REG(SSTATAR);
31 DW_REG(DSTATAR);
32 u32 CFG_LO; /* Configuration Register Low */
33 u32 CFG_HI; /* Configuration Register High */
34 DW_REG(SGR);
35 DW_REG(DSR);
36 };
37
38 struct dw_dma_irq_regs {
39 DW_REG(XFER);
40 DW_REG(BLOCK);
41 DW_REG(SRC_TRAN);
42 DW_REG(DST_TRAN);
43 DW_REG(ERROR);
44 };
45
46 struct dw_dma_regs {
47 /* per-channel registers */
48 struct dw_dma_chan_regs CHAN[DW_DMA_MAX_NR_CHANNELS];
49
50 /* irq handling */
51 struct dw_dma_irq_regs RAW; /* r */
52 struct dw_dma_irq_regs STATUS; /* r (raw & mask) */
53 struct dw_dma_irq_regs MASK; /* rw (set = irq enabled) */
54 struct dw_dma_irq_regs CLEAR; /* w (ack, affects "raw") */
55
56 DW_REG(STATUS_INT); /* r */
57
58 /* software handshaking */
59 DW_REG(REQ_SRC);
60 DW_REG(REQ_DST);
61 DW_REG(SGL_REQ_SRC);
62 DW_REG(SGL_REQ_DST);
63 DW_REG(LAST_SRC);
64 DW_REG(LAST_DST);
65
66 /* miscellaneous */
67 DW_REG(CFG);
68 DW_REG(CH_EN);
69 DW_REG(ID);
70 DW_REG(TEST);
71
72 /* optional encoded params, 0x3c8..0x3 */
73 };
74
75 /* Bitfields in CTL_LO */
76 #define DWC_CTLL_INT_EN (1 << 0) /* irqs enabled? */
77 #define DWC_CTLL_DST_WIDTH(n) ((n)<<1) /* bytes per element */
78 #define DWC_CTLL_SRC_WIDTH(n) ((n)<<4)
79 #define DWC_CTLL_DST_INC (0<<7) /* DAR update/not */
80 #define DWC_CTLL_DST_DEC (1<<7)
81 #define DWC_CTLL_DST_FIX (2<<7)
82 #define DWC_CTLL_SRC_INC (0<<7) /* SAR update/not */
83 #define DWC_CTLL_SRC_DEC (1<<9)
84 #define DWC_CTLL_SRC_FIX (2<<9)
85 #define DWC_CTLL_DST_MSIZE(n) ((n)<<11) /* burst, #elements */
86 #define DWC_CTLL_SRC_MSIZE(n) ((n)<<14)
87 #define DWC_CTLL_S_GATH_EN (1 << 17) /* src gather, !FIX */
88 #define DWC_CTLL_D_SCAT_EN (1 << 18) /* dst scatter, !FIX */
89 #define DWC_CTLL_FC_M2M (0 << 20) /* mem-to-mem */
90 #define DWC_CTLL_FC_M2P (1 << 20) /* mem-to-periph */
91 #define DWC_CTLL_FC_P2M (2 << 20) /* periph-to-mem */
92 #define DWC_CTLL_FC_P2P (3 << 20) /* periph-to-periph */
93 /* plus 4 transfer types for peripheral-as-flow-controller */
94 #define DWC_CTLL_DMS(n) ((n)<<23) /* dst master select */
95 #define DWC_CTLL_SMS(n) ((n)<<25) /* src master select */
96 #define DWC_CTLL_LLP_D_EN (1 << 27) /* dest block chain */
97 #define DWC_CTLL_LLP_S_EN (1 << 28) /* src block chain */
98
99 /* Bitfields in CTL_HI */
100 #define DWC_CTLH_DONE 0x00001000
101 #define DWC_CTLH_BLOCK_TS_MASK 0x00000fff
102
103 /* Bitfields in CFG_LO. Platform-configurable bits are in <linux/dw_dmac.h> */
104 #define DWC_CFGL_CH_SUSP (1 << 8) /* pause xfer */
105 #define DWC_CFGL_FIFO_EMPTY (1 << 9) /* pause xfer */
106 #define DWC_CFGL_HS_DST (1 << 10) /* handshake w/dst */
107 #define DWC_CFGL_HS_SRC (1 << 11) /* handshake w/src */
108 #define DWC_CFGL_MAX_BURST(x) ((x) << 20)
109 #define DWC_CFGL_RELOAD_SAR (1 << 30)
110 #define DWC_CFGL_RELOAD_DAR (1 << 31)
111
112 /* Bitfields in CFG_HI. Platform-configurable bits are in <linux/dw_dmac.h> */
113 #define DWC_CFGH_DS_UPD_EN (1 << 5)
114 #define DWC_CFGH_SS_UPD_EN (1 << 6)
115
116 /* Bitfields in SGR */
117 #define DWC_SGR_SGI(x) ((x) << 0)
118 #define DWC_SGR_SGC(x) ((x) << 20)
119
120 /* Bitfields in DSR */
121 #define DWC_DSR_DSI(x) ((x) << 0)
122 #define DWC_DSR_DSC(x) ((x) << 20)
123
124 /* Bitfields in CFG */
125 #define DW_CFG_DMA_EN (1 << 0)
126
127 #define DW_REGLEN 0x400
128
129 struct dw_dma_chan {
130 struct dma_chan chan;
131 void __iomem *ch_regs;
132 u8 mask;
133
134 spinlock_t lock;
135
136 /* these other elements are all protected by lock */
137 dma_cookie_t completed;
138 struct list_head active_list;
139 struct list_head queue;
140 struct list_head free_list;
141
142 unsigned int descs_allocated;
143 };
144
145 static inline struct dw_dma_chan_regs __iomem *
__dwc_regs(struct dw_dma_chan * dwc)146 __dwc_regs(struct dw_dma_chan *dwc)
147 {
148 return dwc->ch_regs;
149 }
150
151 #define channel_readl(dwc, name) \
152 __raw_readl(&(__dwc_regs(dwc)->name))
153 #define channel_writel(dwc, name, val) \
154 __raw_writel((val), &(__dwc_regs(dwc)->name))
155
to_dw_dma_chan(struct dma_chan * chan)156 static inline struct dw_dma_chan *to_dw_dma_chan(struct dma_chan *chan)
157 {
158 return container_of(chan, struct dw_dma_chan, chan);
159 }
160
161
162 struct dw_dma {
163 struct dma_device dma;
164 void __iomem *regs;
165 struct tasklet_struct tasklet;
166 struct clk *clk;
167
168 u8 all_chan_mask;
169
170 struct dw_dma_chan chan[0];
171 };
172
__dw_regs(struct dw_dma * dw)173 static inline struct dw_dma_regs __iomem *__dw_regs(struct dw_dma *dw)
174 {
175 return dw->regs;
176 }
177
178 #define dma_readl(dw, name) \
179 __raw_readl(&(__dw_regs(dw)->name))
180 #define dma_writel(dw, name, val) \
181 __raw_writel((val), &(__dw_regs(dw)->name))
182
183 #define channel_set_bit(dw, reg, mask) \
184 dma_writel(dw, reg, ((mask) << 8) | (mask))
185 #define channel_clear_bit(dw, reg, mask) \
186 dma_writel(dw, reg, ((mask) << 8) | 0)
187
to_dw_dma(struct dma_device * ddev)188 static inline struct dw_dma *to_dw_dma(struct dma_device *ddev)
189 {
190 return container_of(ddev, struct dw_dma, dma);
191 }
192
193 /* LLI == Linked List Item; a.k.a. DMA block descriptor */
194 struct dw_lli {
195 /* values that are not changed by hardware */
196 dma_addr_t sar;
197 dma_addr_t dar;
198 dma_addr_t llp; /* chain to next lli */
199 u32 ctllo;
200 /* values that may get written back: */
201 u32 ctlhi;
202 /* sstat and dstat can snapshot peripheral register state.
203 * silicon config may discard either or both...
204 */
205 u32 sstat;
206 u32 dstat;
207 };
208
209 struct dw_desc {
210 /* FIRST values the hardware uses */
211 struct dw_lli lli;
212
213 /* THEN values for driver housekeeping */
214 struct list_head desc_node;
215 struct dma_async_tx_descriptor txd;
216 size_t len;
217 };
218
219 static inline struct dw_desc *
txd_to_dw_desc(struct dma_async_tx_descriptor * txd)220 txd_to_dw_desc(struct dma_async_tx_descriptor *txd)
221 {
222 return container_of(txd, struct dw_desc, txd);
223 }
224