arch/arm/mach-omap2/dma.c

   1 /*
   2  * OMAP2+ DMA driver
   3  *
   4  * Copyright (C) 2003 - 2008 Nokia Corporation
   5  * Author: Juha Yrjölä <juha.yrjola@nokia.com>
   6  * DMA channel linking for 1610 by Samuel Ortiz <samuel.ortiz@nokia.com>
   7  * Graphics DMA and LCD DMA graphics tranformations
   8  * by Imre Deak <imre.deak@nokia.com>
   9  * OMAP2/3 support Copyright (C) 2004-2007 Texas Instruments, Inc.
  10  * Some functions based on earlier dma-omap.c Copyright (C) 2001 RidgeRun, Inc.
  11  *
  12  * Copyright (C) 2009 Texas Instruments
  13  * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
  14  *
  15  * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com/
  16  * Converted DMA library into platform driver
  17  *      - G, Manjunath Kondaiah <manjugk@ti.com>
  18  *
  19  * This program is free software; you can redistribute it and/or modify
  20  * it under the terms of the GNU General Public License version 2 as
  21  * published by the Free Software Foundation.
  22  */
  23
  24 #include <linux/err.h>
  25 #include <linux/io.h>
  26 #include <linux/slab.h>
  27 #include <linux/module.h>
  28 #include <linux/init.h>
  29 #include <linux/device.h>
  30 #include <linux/dma-mapping.h>
  31 #include <linux/dmaengine.h>
  32 #include <linux/of.h>
  33 #include <linux/omap-dma.h>
  34
  35 #include "soc.h"
  36 #include "omap_hwmod.h"
  37 #include "omap_device.h"
  38
  39 static enum omap_reg_offsets dma_common_ch_end;
  40
  41 static const struct omap_dma_reg reg_map[] = {
  42         [REVISION]      = { 0x0000, 0x00, OMAP_DMA_REG_32BIT },
  43         [GCR]           = { 0x0078, 0x00, OMAP_DMA_REG_32BIT },
  44         [IRQSTATUS_L0]  = { 0x0008, 0x00, OMAP_DMA_REG_32BIT },
  45         [IRQSTATUS_L1]  = { 0x000c, 0x00, OMAP_DMA_REG_32BIT },
  46         [IRQSTATUS_L2]  = { 0x0010, 0x00, OMAP_DMA_REG_32BIT },
  47         [IRQSTATUS_L3]  = { 0x0014, 0x00, OMAP_DMA_REG_32BIT },
  48         [IRQENABLE_L0]  = { 0x0018, 0x00, OMAP_DMA_REG_32BIT },
  49         [IRQENABLE_L1]  = { 0x001c, 0x00, OMAP_DMA_REG_32BIT },
  50         [IRQENABLE_L2]  = { 0x0020, 0x00, OMAP_DMA_REG_32BIT },
  51         [IRQENABLE_L3]  = { 0x0024, 0x00, OMAP_DMA_REG_32BIT },
  52         [SYSSTATUS]     = { 0x0028, 0x00, OMAP_DMA_REG_32BIT },
  53         [OCP_SYSCONFIG] = { 0x002c, 0x00, OMAP_DMA_REG_32BIT },
  54         [CAPS_0]        = { 0x0064, 0x00, OMAP_DMA_REG_32BIT },
  55         [CAPS_2]        = { 0x006c, 0x00, OMAP_DMA_REG_32BIT },
  56         [CAPS_3]        = { 0x0070, 0x00, OMAP_DMA_REG_32BIT },
  57         [CAPS_4]        = { 0x0074, 0x00, OMAP_DMA_REG_32BIT },
  58
  59         /* Common register offsets */
  60         [CCR]           = { 0x0080, 0x60, OMAP_DMA_REG_32BIT },
  61         [CLNK_CTRL]     = { 0x0084, 0x60, OMAP_DMA_REG_32BIT },
  62         [CICR]          = { 0x0088, 0x60, OMAP_DMA_REG_32BIT },
  63         [CSR]           = { 0x008c, 0x60, OMAP_DMA_REG_32BIT },
  64         [CSDP]          = { 0x0090, 0x60, OMAP_DMA_REG_32BIT },
  65         [CEN]           = { 0x0094, 0x60, OMAP_DMA_REG_32BIT },
  66         [CFN]           = { 0x0098, 0x60, OMAP_DMA_REG_32BIT },
  67         [CSEI]          = { 0x00a4, 0x60, OMAP_DMA_REG_32BIT },
  68         [CSFI]          = { 0x00a8, 0x60, OMAP_DMA_REG_32BIT },
  69         [CDEI]          = { 0x00ac, 0x60, OMAP_DMA_REG_32BIT },
  70         [CDFI]          = { 0x00b0, 0x60, OMAP_DMA_REG_32BIT },
  71         [CSAC]          = { 0x00b4, 0x60, OMAP_DMA_REG_32BIT },
  72         [CDAC]          = { 0x00b8, 0x60, OMAP_DMA_REG_32BIT },
  73
  74         /* Channel specific register offsets */
  75         [CSSA]          = { 0x009c, 0x60, OMAP_DMA_REG_32BIT },
  76         [CDSA]          = { 0x00a0, 0x60, OMAP_DMA_REG_32BIT },
  77         [CCEN]          = { 0x00bc, 0x60, OMAP_DMA_REG_32BIT },
  78         [CCFN]          = { 0x00c0, 0x60, OMAP_DMA_REG_32BIT },
  79         [COLOR]         = { 0x00c4, 0x60, OMAP_DMA_REG_32BIT },
  80
  81         /* OMAP4 specific registers */
  82         [CDP]           = { 0x00d0, 0x60, OMAP_DMA_REG_32BIT },
  83         [CNDP]          = { 0x00d4, 0x60, OMAP_DMA_REG_32BIT },
  84         [CCDN]          = { 0x00d8, 0x60, OMAP_DMA_REG_32BIT },
  85 };
  86
  87 static void __iomem *dma_base;
  88 static inline void dma_write(u32 val, int reg, int lch)
  89 {
  90         void __iomem *addr = dma_base;
  91
  92         addr += reg_map[reg].offset;
  93         addr += reg_map[reg].stride * lch;
  94
  95         writel_relaxed(val, addr);
  96 }
  97
  98 static inline u32 dma_read(int reg, int lch)
  99 {
 100         void __iomem *addr = dma_base;
 101
 102         addr += reg_map[reg].offset;
 103         addr += reg_map[reg].stride * lch;
 104
 105         return readl_relaxed(addr);
 106 }
 107
 108 static void omap2_clear_dma(int lch)
 109 {
 110         int i;
 111
 112         for (i = CSDP; i <= dma_common_ch_end; i += 1)
 113                 dma_write(0, i, lch);
 114 }
 115
 116 static void omap2_show_dma_caps(void)
 117 {
 118         u8 revision = dma_read(REVISION, 0) & 0xff;
 119         printk(KERN_INFO "OMAP DMA hardware revision %d.%d\n",
 120                                 revision >> 4, revision & 0xf);
 121 }
 122
 123 static unsigned configure_dma_errata(void)
 124 {
 125         unsigned errata = 0;
 126
 127         /*
 128          * Errata applicable for OMAP2430ES1.0 and all omap2420
 129          *
 130          * I.
 131          * Erratum ID: Not Available
 132          * Inter Frame DMA buffering issue DMA will wrongly
 133          * buffer elements if packing and bursting is enabled. This might
 134          * result in data gets stalled in FIFO at the end of the block.
 135          * Workaround: DMA channels must have BUFFERING_DISABLED bit set to
 136          * guarantee no data will stay in the DMA FIFO in case inter frame
 137          * buffering occurs
 138          *
 139          * II.
 140          * Erratum ID: Not Available
 141          * DMA may hang when several channels are used in parallel
 142          * In the following configuration, DMA channel hanging can occur:
 143          * a. Channel i, hardware synchronized, is enabled
 144          * b. Another channel (Channel x), software synchronized, is enabled.
 145          * c. Channel i is disabled before end of transfer
 146          * d. Channel i is reenabled.
 147          * e. Steps 1 to 4 are repeated a certain number of times.
 148          * f. A third channel (Channel y), software synchronized, is enabled.
 149          * Channel x and Channel y may hang immediately after step 'f'.
 150          * Workaround:
 151          * For any channel used - make sure NextLCH_ID is set to the value j.
 152          */
 153         if (cpu_is_omap2420() || (cpu_is_omap2430() &&
 154                                 (omap_type() == OMAP2430_REV_ES1_0))) {
 155
 156                 SET_DMA_ERRATA(DMA_ERRATA_IFRAME_BUFFERING);
 157                 SET_DMA_ERRATA(DMA_ERRATA_PARALLEL_CHANNELS);
 158         }
 159
 160         /*
 161          * Erratum ID: i378: OMAP2+: sDMA Channel is not disabled
 162          * after a transaction error.
 163          * Workaround: SW should explicitely disable the channel.
 164          */
 165         if (cpu_class_is_omap2())
 166                 SET_DMA_ERRATA(DMA_ERRATA_i378);
 167
 168         /*
 169          * Erratum ID: i541: sDMA FIFO draining does not finish
 170          * If sDMA channel is disabled on the fly, sDMA enters standby even
 171          * through FIFO Drain is still in progress
 172          * Workaround: Put sDMA in NoStandby more before a logical channel is
 173          * disabled, then put it back to SmartStandby right after the channel
 174          * finishes FIFO draining.
 175          */
 176         if (cpu_is_omap34xx())
 177                 SET_DMA_ERRATA(DMA_ERRATA_i541);
 178
 179         /*
 180          * Erratum ID: i88 : Special programming model needed to disable DMA
 181          * before end of block.
 182          * Workaround: software must ensure that the DMA is configured in No
 183          * Standby mode(DMAx_OCP_SYSCONFIG.MIDLEMODE = "01")
 184          */
 185         if (omap_type() == OMAP3430_REV_ES1_0)
 186                 SET_DMA_ERRATA(DMA_ERRATA_i88);
 187
 188         /*
 189          * Erratum 3.2/3.3: sometimes 0 is returned if CSAC/CDAC is
 190          * read before the DMA controller finished disabling the channel.
 191          */
 192         SET_DMA_ERRATA(DMA_ERRATA_3_3);
 193
 194         /*
 195          * Erratum ID: Not Available
 196          * A bug in ROM code leaves IRQ status for channels 0 and 1 uncleared
 197          * after secure sram context save and restore.
 198          * Work around: Hence we need to manually clear those IRQs to avoid
 199          * spurious interrupts. This affects only secure devices.
 200          */
 201         if (cpu_is_omap34xx() && (omap_type() != OMAP2_DEVICE_TYPE_GP))
 202                 SET_DMA_ERRATA(DMA_ROMCODE_BUG);
 203
 204         return errata;
 205 }
 206
 207 static const struct dma_slave_map omap24xx_sdma_map[] = {
 208         { "omap-gpmc", "rxtx", SDMA_FILTER_PARAM(4) },
 209         { "omap-aes", "tx", SDMA_FILTER_PARAM(9) },
 210         { "omap-aes", "rx", SDMA_FILTER_PARAM(10) },
 211         { "omap-sham", "rx", SDMA_FILTER_PARAM(13) },
 212         { "omap2_mcspi.2", "tx0", SDMA_FILTER_PARAM(15) },
 213         { "omap2_mcspi.2", "rx0", SDMA_FILTER_PARAM(16) },
 214         { "omap-mcbsp.3", "tx", SDMA_FILTER_PARAM(17) },
 215         { "omap-mcbsp.3", "rx", SDMA_FILTER_PARAM(18) },
 216         { "omap-mcbsp.4", "tx", SDMA_FILTER_PARAM(19) },
 217         { "omap-mcbsp.4", "rx", SDMA_FILTER_PARAM(20) },
 218         { "omap-mcbsp.5", "tx", SDMA_FILTER_PARAM(21) },
 219         { "omap-mcbsp.5", "rx", SDMA_FILTER_PARAM(22) },
 220         { "omap2_mcspi.2", "tx1", SDMA_FILTER_PARAM(23) },
 221         { "omap2_mcspi.2", "rx1", SDMA_FILTER_PARAM(24) },
 222         { "omap_i2c.1", "tx", SDMA_FILTER_PARAM(27) },
 223         { "omap_i2c.1", "rx", SDMA_FILTER_PARAM(28) },
 224         { "omap_i2c.2", "tx", SDMA_FILTER_PARAM(29) },
 225         { "omap_i2c.2", "rx", SDMA_FILTER_PARAM(30) },
 226         { "omap-mcbsp.1", "tx", SDMA_FILTER_PARAM(31) },
 227         { "omap-mcbsp.1", "rx", SDMA_FILTER_PARAM(32) },
 228         { "omap-mcbsp.2", "tx", SDMA_FILTER_PARAM(33) },
 229         { "omap-mcbsp.2", "rx", SDMA_FILTER_PARAM(34) },
 230         { "omap2_mcspi.0", "tx0", SDMA_FILTER_PARAM(35) },
 231         { "omap2_mcspi.0", "rx0", SDMA_FILTER_PARAM(36) },
 232         { "omap2_mcspi.0", "tx1", SDMA_FILTER_PARAM(37) },
 233         { "omap2_mcspi.0", "rx1", SDMA_FILTER_PARAM(38) },
 234         { "omap2_mcspi.0", "tx2", SDMA_FILTER_PARAM(39) },
 235         { "omap2_mcspi.0", "rx2", SDMA_FILTER_PARAM(40) },
 236         { "omap2_mcspi.0", "tx3", SDMA_FILTER_PARAM(41) },
 237         { "omap2_mcspi.0", "rx3", SDMA_FILTER_PARAM(42) },
 238         { "omap2_mcspi.1", "tx0", SDMA_FILTER_PARAM(43) },
 239         { "omap2_mcspi.1", "rx0", SDMA_FILTER_PARAM(44) },
 240         { "omap2_mcspi.1", "tx1", SDMA_FILTER_PARAM(45) },
 241         { "omap2_mcspi.1", "rx1", SDMA_FILTER_PARAM(46) },
 242         { "omap_hsmmc.1", "tx", SDMA_FILTER_PARAM(47) },
 243         { "omap_hsmmc.1", "rx", SDMA_FILTER_PARAM(48) },
 244         { "omap_uart.0", "tx", SDMA_FILTER_PARAM(49) },
 245         { "omap_uart.0", "rx", SDMA_FILTER_PARAM(50) },
 246         { "omap_uart.1", "tx", SDMA_FILTER_PARAM(51) },
 247         { "omap_uart.1", "rx", SDMA_FILTER_PARAM(52) },
 248         { "omap_uart.2", "tx", SDMA_FILTER_PARAM(53) },
 249         { "omap_uart.2", "rx", SDMA_FILTER_PARAM(54) },
 250         { "omap_hsmmc.0", "tx", SDMA_FILTER_PARAM(61) },
 251         { "omap_hsmmc.0", "rx", SDMA_FILTER_PARAM(62) },
 252
 253         /* external DMA requests when tusb6010 is used */
 254         { "musb-tusb", "dmareq0", SDMA_FILTER_PARAM(2) },
 255         { "musb-tusb", "dmareq1", SDMA_FILTER_PARAM(3) },
 256         { "musb-tusb", "dmareq2", SDMA_FILTER_PARAM(14) }, /* OMAP2420 only */
 257         { "musb-tusb", "dmareq3", SDMA_FILTER_PARAM(15) }, /* OMAP2420 only */
 258         { "musb-tusb", "dmareq4", SDMA_FILTER_PARAM(16) }, /* OMAP2420 only */
 259         { "musb-tusb", "dmareq5", SDMA_FILTER_PARAM(64) }, /* OMAP2420 only */
 260 };
 261
 262 static const struct dma_slave_map omap24xx_sdma_dt_map[] = {
 263         /* external DMA requests when tusb6010 is used */
 264         { "musb-hdrc.1.auto", "dmareq0", SDMA_FILTER_PARAM(2) },
 265         { "musb-hdrc.1.auto", "dmareq1", SDMA_FILTER_PARAM(3) },
 266         { "musb-hdrc.1.auto", "dmareq2", SDMA_FILTER_PARAM(14) }, /* OMAP2420 only */
 267         { "musb-hdrc.1.auto", "dmareq3", SDMA_FILTER_PARAM(15) }, /* OMAP2420 only */
 268         { "musb-hdrc.1.auto", "dmareq4", SDMA_FILTER_PARAM(16) }, /* OMAP2420 only */
 269         { "musb-hdrc.1.auto", "dmareq5", SDMA_FILTER_PARAM(64) }, /* OMAP2420 only */
 270 };
 271
 272 static const struct dma_slave_map omap3xxx_sdma_map[] = {
 273         { "omap-gpmc", "rxtx", SDMA_FILTER_PARAM(4) },
 274         { "omap2_mcspi.2", "tx0", SDMA_FILTER_PARAM(15) },
 275         { "omap2_mcspi.2", "rx0", SDMA_FILTER_PARAM(16) },
 276         { "omap-mcbsp.3", "tx", SDMA_FILTER_PARAM(17) },
 277         { "omap-mcbsp.3", "rx", SDMA_FILTER_PARAM(18) },
 278         { "omap-mcbsp.4", "tx", SDMA_FILTER_PARAM(19) },
 279         { "omap-mcbsp.4", "rx", SDMA_FILTER_PARAM(20) },
 280         { "omap-mcbsp.5", "tx", SDMA_FILTER_PARAM(21) },
 281         { "omap-mcbsp.5", "rx", SDMA_FILTER_PARAM(22) },
 282         { "omap2_mcspi.2", "tx1", SDMA_FILTER_PARAM(23) },
 283         { "omap2_mcspi.2", "rx1", SDMA_FILTER_PARAM(24) },
 284         { "omap_i2c.3", "tx", SDMA_FILTER_PARAM(25) },
 285         { "omap_i2c.3", "rx", SDMA_FILTER_PARAM(26) },
 286         { "omap_i2c.1", "tx", SDMA_FILTER_PARAM(27) },
 287         { "omap_i2c.1", "rx", SDMA_FILTER_PARAM(28) },
 288         { "omap_i2c.2", "tx", SDMA_FILTER_PARAM(29) },
 289         { "omap_i2c.2", "rx", SDMA_FILTER_PARAM(30) },
 290         { "omap-mcbsp.1", "tx", SDMA_FILTER_PARAM(31) },
 291         { "omap-mcbsp.1", "rx", SDMA_FILTER_PARAM(32) },
 292         { "omap-mcbsp.2", "tx", SDMA_FILTER_PARAM(33) },
 293         { "omap-mcbsp.2", "rx", SDMA_FILTER_PARAM(34) },
 294         { "omap2_mcspi.0", "tx0", SDMA_FILTER_PARAM(35) },
 295         { "omap2_mcspi.0", "rx0", SDMA_FILTER_PARAM(36) },
 296         { "omap2_mcspi.0", "tx1", SDMA_FILTER_PARAM(37) },
 297         { "omap2_mcspi.0", "rx1", SDMA_FILTER_PARAM(38) },
 298         { "omap2_mcspi.0", "tx2", SDMA_FILTER_PARAM(39) },
 299         { "omap2_mcspi.0", "rx2", SDMA_FILTER_PARAM(40) },
 300         { "omap2_mcspi.0", "tx3", SDMA_FILTER_PARAM(41) },
 301         { "omap2_mcspi.0", "rx3", SDMA_FILTER_PARAM(42) },
 302         { "omap2_mcspi.1", "tx0", SDMA_FILTER_PARAM(43) },
 303         { "omap2_mcspi.1", "rx0", SDMA_FILTER_PARAM(44) },
 304         { "omap2_mcspi.1", "tx1", SDMA_FILTER_PARAM(45) },
 305         { "omap2_mcspi.1", "rx1", SDMA_FILTER_PARAM(46) },
 306         { "omap_hsmmc.1", "tx", SDMA_FILTER_PARAM(47) },
 307         { "omap_hsmmc.1", "rx", SDMA_FILTER_PARAM(48) },
 308         { "omap_uart.0", "tx", SDMA_FILTER_PARAM(49) },
 309         { "omap_uart.0", "rx", SDMA_FILTER_PARAM(50) },
 310         { "omap_uart.1", "tx", SDMA_FILTER_PARAM(51) },
 311         { "omap_uart.1", "rx", SDMA_FILTER_PARAM(52) },
 312         { "omap_uart.2", "tx", SDMA_FILTER_PARAM(53) },
 313         { "omap_uart.2", "rx", SDMA_FILTER_PARAM(54) },
 314         { "omap_hsmmc.0", "tx", SDMA_FILTER_PARAM(61) },
 315         { "omap_hsmmc.0", "rx", SDMA_FILTER_PARAM(62) },
 316         { "omap-aes", "tx", SDMA_FILTER_PARAM(65) },
 317         { "omap-aes", "rx", SDMA_FILTER_PARAM(66) },
 318         { "omap-sham", "rx", SDMA_FILTER_PARAM(69) },
 319         { "omap2_mcspi.3", "tx0", SDMA_FILTER_PARAM(70) },
 320         { "omap2_mcspi.3", "rx0", SDMA_FILTER_PARAM(71) },
 321         { "omap_hsmmc.2", "tx", SDMA_FILTER_PARAM(77) },
 322         { "omap_hsmmc.2", "rx", SDMA_FILTER_PARAM(78) },
 323         { "omap_uart.3", "tx", SDMA_FILTER_PARAM(81) },
 324         { "omap_uart.3", "rx", SDMA_FILTER_PARAM(82) },
 325 };
 326
 327 static struct omap_system_dma_plat_info dma_plat_info __initdata = {
 328         .reg_map        = reg_map,
 329         .channel_stride = 0x60,
 330         .show_dma_caps  = omap2_show_dma_caps,
 331         .clear_dma      = omap2_clear_dma,
 332         .dma_write      = dma_write,
 333         .dma_read       = dma_read,
 334 };
 335
 336 static struct platform_device_info omap_dma_dev_info = {
 337         .name = "omap-dma-engine",
 338         .id = -1,
 339         .dma_mask = DMA_BIT_MASK(32),
 340 };
 341
 342 /* One time initializations */
 343 static int __init omap2_system_dma_init_dev(struct omap_hwmod *oh, void *unused)
 344 {
 345         struct platform_device                  *pdev;
 346         struct omap_system_dma_plat_info        p;
 347         struct omap_dma_dev_attr                *d;
 348         struct resource                         *mem;
 349         char                                    *name = "omap_dma_system";
 350
 351         p = dma_plat_info;
 352         p.dma_attr = (struct omap_dma_dev_attr *)oh->dev_attr;
 353         p.errata = configure_dma_errata();
 354
 355         if (!of_have_populated_dt()) {
 356                 if (soc_is_omap24xx()) {
 357                         p.slave_map = omap24xx_sdma_map;
 358                         p.slavecnt = ARRAY_SIZE(omap24xx_sdma_map);
 359                 } else if (soc_is_omap34xx() || soc_is_omap3630()) {
 360                         p.slave_map = omap3xxx_sdma_map;
 361                         p.slavecnt = ARRAY_SIZE(omap3xxx_sdma_map);
 362                 } else {
 363                         pr_err("%s: The legacy DMA map is not provided!\n",
 364                                __func__);
 365                         return -ENODEV;
 366                 }
 367         } else {
 368                 if (soc_is_omap24xx()) {
 369                         /* DMA slave map for drivers not yet converted to DT */
 370                         p.slave_map = omap24xx_sdma_dt_map;
 371                         p.slavecnt = ARRAY_SIZE(omap24xx_sdma_dt_map);
 372                 }
 373         }
 374
 375         pdev = omap_device_build(name, 0, oh, &p, sizeof(p));
 376         if (IS_ERR(pdev)) {
 377                 pr_err("%s: Can't build omap_device for %s:%s.\n",
 378                         __func__, name, oh->name);
 379                 return PTR_ERR(pdev);
 380         }
 381
 382         omap_dma_dev_info.res = pdev->resource;
 383         omap_dma_dev_info.num_res = pdev->num_resources;
 384
 385         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 386         if (!mem) {
 387                 dev_err(&pdev->dev, "%s: no mem resource\n", __func__);
 388                 return -EINVAL;
 389         }
 390
 391         dma_base = ioremap(mem->start, resource_size(mem));
 392         if (!dma_base) {
 393                 dev_err(&pdev->dev, "%s: ioremap fail\n", __func__);
 394                 return -ENOMEM;
 395         }
 396
 397         d = oh->dev_attr;
 398
 399         if (cpu_is_omap34xx() && (omap_type() != OMAP2_DEVICE_TYPE_GP))
 400                 d->dev_caps |= HS_CHANNELS_RESERVED;
 401
 402         if (platform_get_irq_byname(pdev, "0") < 0)
 403                 d->dev_caps |= DMA_ENGINE_HANDLE_IRQ;
 404
 405         /* Check the capabilities register for descriptor loading feature */
 406         if (dma_read(CAPS_0, 0) & DMA_HAS_DESCRIPTOR_CAPS)
 407                 dma_common_ch_end = CCDN;
 408         else
 409                 dma_common_ch_end = CCFN;
 410
 411         return 0;
 412 }
 413
 414 static int __init omap2_system_dma_init(void)
 415 {
 416         struct platform_device *pdev;
 417         int res;
 418
 419         res = omap_hwmod_for_each_by_class("dma",
 420                         omap2_system_dma_init_dev, NULL);
 421         if (res)
 422                 return res;
 423
 424         if (of_have_populated_dt())
 425                 return res;
 426
 427         pdev = platform_device_register_full(&omap_dma_dev_info);
 428         if (IS_ERR(pdev))
 429                 return PTR_ERR(pdev);
 430
 431         return res;
 432 }
 433 omap_arch_initcall(omap2_system_dma_init);