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/*
  17 * Redefine this macro to handle differences between 32- and 64-bit
  18 * addressing, big vs. little endian, etc.
  19 */
  20#define DW_REG(name)            u32 name; u32 __pad_##name
  21
  22/* Hardware register definitions. */
  23struct dw_dma_chan_regs {
  24        DW_REG(SAR);            /* Source Address Register */
  25        DW_REG(DAR);            /* Destination Address Register */
  26        DW_REG(LLP);            /* Linked List Pointer */
  27        u32     CTL_LO;         /* Control Register Low */
  28        u32     CTL_HI;         /* Control Register High */
  29        DW_REG(SSTAT);
  30        DW_REG(DSTAT);
  31        DW_REG(SSTATAR);
  32        DW_REG(DSTATAR);
  33        u32     CFG_LO;         /* Configuration Register Low */
  34        u32     CFG_HI;         /* Configuration Register High */
  35        DW_REG(SGR);
  36        DW_REG(DSR);
  37};
  38
  39struct dw_dma_irq_regs {
  40        DW_REG(XFER);
  41        DW_REG(BLOCK);
  42        DW_REG(SRC_TRAN);
  43        DW_REG(DST_TRAN);
  44        DW_REG(ERROR);
  45};
  46
  47struct dw_dma_regs {
  48        /* per-channel registers */
  49        struct dw_dma_chan_regs CHAN[DW_DMA_MAX_NR_CHANNELS];
  50
  51        /* irq handling */
  52        struct dw_dma_irq_regs  RAW;            /* r */
  53        struct dw_dma_irq_regs  STATUS;         /* r (raw & mask) */
  54        struct dw_dma_irq_regs  MASK;           /* rw (set = irq enabled) */
  55        struct dw_dma_irq_regs  CLEAR;          /* w (ack, affects "raw") */
  56
  57        DW_REG(STATUS_INT);                     /* r */
  58
  59        /* software handshaking */
  60        DW_REG(REQ_SRC);
  61        DW_REG(REQ_DST);
  62        DW_REG(SGL_REQ_SRC);
  63        DW_REG(SGL_REQ_DST);
  64        DW_REG(LAST_SRC);
  65        DW_REG(LAST_DST);
  66
  67        /* miscellaneous */
  68        DW_REG(CFG);
  69        DW_REG(CH_EN);
  70        DW_REG(ID);
  71        DW_REG(TEST);
  72
  73        /* optional encoded params, 0x3c8..0x3 */
  74};
  75
  76/* Bitfields in CTL_LO */
  77#define DWC_CTLL_INT_EN         (1 << 0)        /* irqs enabled? */
  78#define DWC_CTLL_DST_WIDTH(n)   ((n)<<1)        /* bytes per element */
  79#define DWC_CTLL_SRC_WIDTH(n)   ((n)<<4)
  80#define DWC_CTLL_DST_INC        (0<<7)          /* DAR update/not */
  81#define DWC_CTLL_DST_DEC        (1<<7)
  82#define DWC_CTLL_DST_FIX        (2<<7)
  83#define DWC_CTLL_SRC_INC        (0<<7)          /* SAR update/not */
  84#define DWC_CTLL_SRC_DEC        (1<<9)
  85#define DWC_CTLL_SRC_FIX        (2<<9)
  86#define DWC_CTLL_DST_MSIZE(n)   ((n)<<11)       /* burst, #elements */
  87#define DWC_CTLL_SRC_MSIZE(n)   ((n)<<14)
  88#define DWC_CTLL_S_GATH_EN      (1 << 17)       /* src gather, !FIX */
  89#define DWC_CTLL_D_SCAT_EN      (1 << 18)       /* dst scatter, !FIX */
  90#define DWC_CTLL_FC(n)          ((n) << 20)
  91#define DWC_CTLL_FC_M2M         (0 << 20)       /* mem-to-mem */
  92#define DWC_CTLL_FC_M2P         (1 << 20)       /* mem-to-periph */
  93#define DWC_CTLL_FC_P2M         (2 << 20)       /* periph-to-mem */
  94#define DWC_CTLL_FC_P2P         (3 << 20)       /* periph-to-periph */
  95/* plus 4 transfer types for peripheral-as-flow-controller */
  96#define DWC_CTLL_DMS(n)         ((n)<<23)       /* dst master select */
  97#define DWC_CTLL_SMS(n)         ((n)<<25)       /* src master select */
  98#define DWC_CTLL_LLP_D_EN       (1 << 27)       /* dest block chain */
  99#define DWC_CTLL_LLP_S_EN       (1 << 28)       /* src block chain */
 100
 101/* Bitfields in CTL_HI */
 102#define DWC_CTLH_DONE           0x00001000
 103#define DWC_CTLH_BLOCK_TS_MASK  0x00000fff
 104
 105/* Bitfields in CFG_LO. Platform-configurable bits are in <linux/dw_dmac.h> */
 106#define DWC_CFGL_CH_PRIOR_MASK  (0x7 << 5)      /* priority mask */
 107#define DWC_CFGL_CH_PRIOR(x)    ((x) << 5)      /* priority */
 108#define DWC_CFGL_CH_SUSP        (1 << 8)        /* pause xfer */
 109#define DWC_CFGL_FIFO_EMPTY     (1 << 9)        /* pause xfer */
 110#define DWC_CFGL_HS_DST         (1 << 10)       /* handshake w/dst */
 111#define DWC_CFGL_HS_SRC         (1 << 11)       /* handshake w/src */
 112#define DWC_CFGL_MAX_BURST(x)   ((x) << 20)
 113#define DWC_CFGL_RELOAD_SAR     (1 << 30)
 114#define DWC_CFGL_RELOAD_DAR     (1 << 31)
 115
 116/* Bitfields in CFG_HI. Platform-configurable bits are in <linux/dw_dmac.h> */
 117#define DWC_CFGH_DS_UPD_EN      (1 << 5)
 118#define DWC_CFGH_SS_UPD_EN      (1 << 6)
 119
 120/* Bitfields in SGR */
 121#define DWC_SGR_SGI(x)          ((x) << 0)
 122#define DWC_SGR_SGC(x)          ((x) << 20)
 123
 124/* Bitfields in DSR */
 125#define DWC_DSR_DSI(x)          ((x) << 0)
 126#define DWC_DSR_DSC(x)          ((x) << 20)
 127
 128/* Bitfields in CFG */
 129#define DW_CFG_DMA_EN           (1 << 0)
 130
 131#define DW_REGLEN               0x400
 132
 133enum dw_dmac_flags {
 134        DW_DMA_IS_CYCLIC = 0,
 135};
 136
 137struct dw_dma_chan {
 138        struct dma_chan         chan;
 139        void __iomem            *ch_regs;
 140        u8                      mask;
 141        u8                      priority;
 142        bool                    paused;
 143        bool                    initialized;
 144
 145        spinlock_t              lock;
 146
 147        /* these other elements are all protected by lock */
 148        unsigned long           flags;
 149        dma_cookie_t            completed;
 150        struct list_head        active_list;
 151        struct list_head        queue;
 152        struct list_head        free_list;
 153        struct dw_cyclic_desc   *cdesc;
 154
 155        unsigned int            descs_allocated;
 156};
 157
 158static inline struct dw_dma_chan_regs __iomem *
 159__dwc_regs(struct dw_dma_chan *dwc)
 160{
 161        return dwc->ch_regs;
 162}
 163
 164#define channel_readl(dwc, name) \
 165        readl(&(__dwc_regs(dwc)->name))
 166#define channel_writel(dwc, name, val) \
 167        writel((val), &(__dwc_regs(dwc)->name))
 168
 169static inline struct dw_dma_chan *to_dw_dma_chan(struct dma_chan *chan)
 170{
 171        return container_of(chan, struct dw_dma_chan, chan);
 172}
 173
 174struct dw_dma {
 175        struct dma_device       dma;
 176        void __iomem            *regs;
 177        struct tasklet_struct   tasklet;
 178        struct clk              *clk;
 179
 180        u8                      all_chan_mask;
 181
 182        struct dw_dma_chan      chan[0];
 183};
 184
 185static inline struct dw_dma_regs __iomem *__dw_regs(struct dw_dma *dw)
 186{
 187        return dw->regs;
 188}
 189
 190#define dma_readl(dw, name) \
 191        readl(&(__dw_regs(dw)->name))
 192#define dma_writel(dw, name, val) \
 193        writel((val), &(__dw_regs(dw)->name))
 194
 195#define channel_set_bit(dw, reg, mask) \
 196        dma_writel(dw, reg, ((mask) << 8) | (mask))
 197#define channel_clear_bit(dw, reg, mask) \
 198        dma_writel(dw, reg, ((mask) << 8) | 0)
 199
 200static inline struct dw_dma *to_dw_dma(struct dma_device *ddev)
 201{
 202        return container_of(ddev, struct dw_dma, dma);
 203}
 204
 205/* LLI == Linked List Item; a.k.a. DMA block descriptor */
 206struct dw_lli {
 207        /* values that are not changed by hardware */
 208        dma_addr_t      sar;
 209        dma_addr_t      dar;
 210        dma_addr_t      llp;            /* chain to next lli */
 211        u32             ctllo;
 212        /* values that may get written back: */
 213        u32             ctlhi;
 214        /* sstat and dstat can snapshot peripheral register state.
 215         * silicon config may discard either or both...
 216         */
 217        u32             sstat;
 218        u32             dstat;
 219};
 220
 221struct dw_desc {
 222        /* FIRST values the hardware uses */
 223        struct dw_lli                   lli;
 224
 225        /* THEN values for driver housekeeping */
 226        struct list_head                desc_node;
 227        struct list_head                tx_list;
 228        struct dma_async_tx_descriptor  txd;
 229        size_t                          len;
 230};
 231
 232static inline struct dw_desc *
 233txd_to_dw_desc(struct dma_async_tx_descriptor *txd)
 234{
 235        return container_of(txd, struct dw_desc, txd);
 236}
 237