LXR linux/drivers/dma/dw_dmac

   1/*
   2 * Driver for the Synopsys DesignWare AHB DMA Controller
   3 *
   4 * Copyright (C) 2005-2007 Atmel Corporation
   5 * Copyright (C) 2010-2011 ST Microelectronics
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as
   9 * published by the Free Software Foundation.
  10 */
  11
  12#include <linux/dw_dmac.h>
  13
  14#define DW_DMA_MAX_NR_CHANNELS  8
  15
  16/* flow controller */
  17enum dw_dma_fc {
  18        DW_DMA_FC_D_M2M,
  19        DW_DMA_FC_D_M2P,
  20        DW_DMA_FC_D_P2M,
  21        DW_DMA_FC_D_P2P,
  22        DW_DMA_FC_P_P2M,
  23        DW_DMA_FC_SP_P2P,
  24        DW_DMA_FC_P_M2P,
  25        DW_DMA_FC_DP_P2P,
  26};
  27
  28/*
  29 * Redefine this macro to handle differences between 32- and 64-bit
  30 * addressing, big vs. little endian, etc.
  31 */
  32#define DW_REG(name)            u32 name; u32 __pad_##name
  33
  34/* Hardware register definitions. */
  35struct dw_dma_chan_regs {
  36        DW_REG(SAR);            /* Source Address Register */
  37        DW_REG(DAR);            /* Destination Address Register */
  38        DW_REG(LLP);            /* Linked List Pointer */
  39        u32     CTL_LO;         /* Control Register Low */
  40        u32     CTL_HI;         /* Control Register High */
  41        DW_REG(SSTAT);
  42        DW_REG(DSTAT);
  43        DW_REG(SSTATAR);
  44        DW_REG(DSTATAR);
  45        u32     CFG_LO;         /* Configuration Register Low */
  46        u32     CFG_HI;         /* Configuration Register High */
  47        DW_REG(SGR);
  48        DW_REG(DSR);
  49};
  50
  51struct dw_dma_irq_regs {
  52        DW_REG(XFER);
  53        DW_REG(BLOCK);
  54        DW_REG(SRC_TRAN);
  55        DW_REG(DST_TRAN);
  56        DW_REG(ERROR);
  57};
  58
  59struct dw_dma_regs {
  60        /* per-channel registers */
  61        struct dw_dma_chan_regs CHAN[DW_DMA_MAX_NR_CHANNELS];
  62
  63        /* irq handling */
  64        struct dw_dma_irq_regs  RAW;            /* r */
  65        struct dw_dma_irq_regs  STATUS;         /* r (raw & mask) */
  66        struct dw_dma_irq_regs  MASK;           /* rw (set = irq enabled) */
  67        struct dw_dma_irq_regs  CLEAR;          /* w (ack, affects "raw") */
  68
  69        DW_REG(STATUS_INT);                     /* r */
  70
  71        /* software handshaking */
  72        DW_REG(REQ_SRC);
  73        DW_REG(REQ_DST);
  74        DW_REG(SGL_REQ_SRC);
  75        DW_REG(SGL_REQ_DST);
  76        DW_REG(LAST_SRC);
  77        DW_REG(LAST_DST);
  78
  79        /* miscellaneous */
  80        DW_REG(CFG);
  81        DW_REG(CH_EN);
  82        DW_REG(ID);
  83        DW_REG(TEST);
  84
  85        /* optional encoded params, 0x3c8..0x3f7 */
  86};
  87
  88/* Bitfields in CTL_LO */
  89#define DWC_CTLL_INT_EN         (1 << 0)        /* irqs enabled? */
  90#define DWC_CTLL_DST_WIDTH(n)   ((n)<<1)        /* bytes per element */
  91#define DWC_CTLL_SRC_WIDTH(n)   ((n)<<4)
  92#define DWC_CTLL_DST_INC        (0<<7)          /* DAR update/not */
  93#define DWC_CTLL_DST_DEC        (1<<7)
  94#define DWC_CTLL_DST_FIX        (2<<7)
  95#define DWC_CTLL_SRC_INC        (0<<7)          /* SAR update/not */
  96#define DWC_CTLL_SRC_DEC        (1<<9)
  97#define DWC_CTLL_SRC_FIX        (2<<9)
  98#define DWC_CTLL_DST_MSIZE(n)   ((n)<<11)       /* burst, #elements */
  99#define DWC_CTLL_SRC_MSIZE(n)   ((n)<<14)
 100#define DWC_CTLL_S_GATH_EN      (1 << 17)       /* src gather, !FIX */
 101#define DWC_CTLL_D_SCAT_EN      (1 << 18)       /* dst scatter, !FIX */
 102#define DWC_CTLL_FC(n)          ((n) << 20)
 103#define DWC_CTLL_FC_M2M         (0 << 20)       /* mem-to-mem */
 104#define DWC_CTLL_FC_M2P         (1 << 20)       /* mem-to-periph */
 105#define DWC_CTLL_FC_P2M         (2 << 20)       /* periph-to-mem */
 106#define DWC_CTLL_FC_P2P         (3 << 20)       /* periph-to-periph */
 107/* plus 4 transfer types for peripheral-as-flow-controller */
 108#define DWC_CTLL_DMS(n)         ((n)<<23)       /* dst master select */
 109#define DWC_CTLL_SMS(n)         ((n)<<25)       /* src master select */
 110#define DWC_CTLL_LLP_D_EN       (1 << 27)       /* dest block chain */
 111#define DWC_CTLL_LLP_S_EN       (1 << 28)       /* src block chain */
 112
 113/* Bitfields in CTL_HI */
 114#define DWC_CTLH_DONE           0x00001000
 115#define DWC_CTLH_BLOCK_TS_MASK  0x00000fff
 116
 117/* Bitfields in CFG_LO. Platform-configurable bits are in <linux/dw_dmac.h> */
 118#define DWC_CFGL_CH_PRIOR_MASK  (0x7 << 5)      /* priority mask */
 119#define DWC_CFGL_CH_PRIOR(x)    ((x) << 5)      /* priority */
 120#define DWC_CFGL_CH_SUSP        (1 << 8)        /* pause xfer */
 121#define DWC_CFGL_FIFO_EMPTY     (1 << 9)        /* pause xfer */
 122#define DWC_CFGL_HS_DST         (1 << 10)       /* handshake w/dst */
 123#define DWC_CFGL_HS_SRC         (1 << 11)       /* handshake w/src */
 124#define DWC_CFGL_MAX_BURST(x)   ((x) << 20)
 125#define DWC_CFGL_RELOAD_SAR     (1 << 30)
 126#define DWC_CFGL_RELOAD_DAR     (1 << 31)
 127
 128/* Bitfields in CFG_HI. Platform-configurable bits are in <linux/dw_dmac.h> */
 129#define DWC_CFGH_DS_UPD_EN      (1 << 5)
 130#define DWC_CFGH_SS_UPD_EN      (1 << 6)
 131
 132/* Bitfields in SGR */
 133#define DWC_SGR_SGI(x)          ((x) << 0)
 134#define DWC_SGR_SGC(x)          ((x) << 20)
 135
 136/* Bitfields in DSR */
 137#define DWC_DSR_DSI(x)          ((x) << 0)
 138#define DWC_DSR_DSC(x)          ((x) << 20)
 139
 140/* Bitfields in CFG */
 141#define DW_CFG_DMA_EN           (1 << 0)
 142
 143#define DW_REGLEN               0x400
 144
 145enum dw_dmac_flags {
 146        DW_DMA_IS_CYCLIC = 0,
 147};
 148
 149struct dw_dma_chan {
 150        struct dma_chan         chan;
 151        void __iomem            *ch_regs;
 152        u8                      mask;
 153        u8                      priority;
 154        bool                    paused;
 155        bool                    initialized;
 156
 157        spinlock_t              lock;
 158
 159        /* these other elements are all protected by lock */
 160        unsigned long           flags;
 161        struct list_head        active_list;
 162        struct list_head        queue;
 163        struct list_head        free_list;
 164        struct dw_cyclic_desc   *cdesc;
 165
 166        unsigned int            descs_allocated;
 167
 168        /* configuration passed via DMA_SLAVE_CONFIG */
 169        struct dma_slave_config dma_sconfig;
 170};
 171
 172static inline struct dw_dma_chan_regs __iomem *
 173__dwc_regs(struct dw_dma_chan *dwc)
 174{
 175        return dwc->ch_regs;
 176}
 177
 178#define channel_readl(dwc, name) \
 179        readl(&(__dwc_regs(dwc)->name))
 180#define channel_writel(dwc, name, val) \
 181        writel((val), &(__dwc_regs(dwc)->name))
 182
 183static inline struct dw_dma_chan *to_dw_dma_chan(struct dma_chan *chan)
 184{
 185        return container_of(chan, struct dw_dma_chan, chan);
 186}
 187
 188struct dw_dma {
 189        struct dma_device       dma;
 190        void __iomem            *regs;
 191        struct tasklet_struct   tasklet;
 192        struct clk              *clk;
 193
 194        u8                      all_chan_mask;
 195
 196        struct dw_dma_chan      chan[0];
 197};
 198
 199static inline struct dw_dma_regs __iomem *__dw_regs(struct dw_dma *dw)
 200{
 201        return dw->regs;
 202}
 203
 204#define dma_readl(dw, name) \
 205        readl(&(__dw_regs(dw)->name))
 206#define dma_writel(dw, name, val) \
 207        writel((val), &(__dw_regs(dw)->name))
 208
 209#define channel_set_bit(dw, reg, mask) \
 210        dma_writel(dw, reg, ((mask) << 8) | (mask))
 211#define channel_clear_bit(dw, reg, mask) \
 212        dma_writel(dw, reg, ((mask) << 8) | 0)
 213
 214static inline struct dw_dma *to_dw_dma(struct dma_device *ddev)
 215{
 216        return container_of(ddev, struct dw_dma, dma);
 217}
 218
 219/* LLI == Linked List Item; a.k.a. DMA block descriptor */
 220struct dw_lli {
 221        /* values that are not changed by hardware */
 222        u32             sar;
 223        u32             dar;
 224        u32             llp;            /* chain to next lli */
 225        u32             ctllo;
 226        /* values that may get written back: */
 227        u32             ctlhi;
 228        /* sstat and dstat can snapshot peripheral register state.
 229         * silicon config may discard either or both...
 230         */
 231        u32             sstat;
 232        u32             dstat;
 233};
 234
 235struct dw_desc {
 236        /* FIRST values the hardware uses */
 237        struct dw_lli                   lli;
 238
 239        /* THEN values for driver housekeeping */
 240        struct list_head                desc_node;
 241        struct list_head                tx_list;
 242        struct dma_async_tx_descriptor  txd;
 243        size_t                          len;
 244};
 245
 246static inline struct dw_desc *
 247txd_to_dw_desc(struct dma_async_tx_descriptor *txd)
 248{
 249        return container_of(txd, struct dw_desc, txd);
 250}
 251