drivers/bus/da8xx-mstpri.c

   1 /*
   2  * TI da8xx master peripheral priority driver
   3  *
   4  * Copyright (C) 2016 BayLibre SAS
   5  *
   6  * Author:
   7  *   Bartosz Golaszewski <bgolaszewski@baylibre.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/io.h>
  18 #include <linux/regmap.h>
  19
  20 /*
  21  * REVISIT: Linux doesn't have a good framework for the kind of performance
  22  * knobs this driver controls. We can't use device tree properties as it deals
  23  * with hardware configuration rather than description. We also don't want to
  24  * commit to maintaining some random sysfs attributes.
  25  *
  26  * For now we just hardcode the register values for the boards that need
  27  * some changes (as is the case for the LCD controller on da850-lcdk - the
  28  * first board we support here). When linux gets an appropriate framework,
  29  * we'll easily convert the driver to it.
  30  */
  31
  32 #define DA8XX_MSTPRI0_OFFSET            0
  33 #define DA8XX_MSTPRI1_OFFSET            4
  34 #define DA8XX_MSTPRI2_OFFSET            8
  35
  36 enum {
  37         DA8XX_MSTPRI_ARM_I = 0,
  38         DA8XX_MSTPRI_ARM_D,
  39         DA8XX_MSTPRI_UPP,
  40         DA8XX_MSTPRI_SATA,
  41         DA8XX_MSTPRI_PRU0,
  42         DA8XX_MSTPRI_PRU1,
  43         DA8XX_MSTPRI_EDMA30TC0,
  44         DA8XX_MSTPRI_EDMA30TC1,
  45         DA8XX_MSTPRI_EDMA31TC0,
  46         DA8XX_MSTPRI_VPIF_DMA_0,
  47         DA8XX_MSTPRI_VPIF_DMA_1,
  48         DA8XX_MSTPRI_EMAC,
  49         DA8XX_MSTPRI_USB0CFG,
  50         DA8XX_MSTPRI_USB0CDMA,
  51         DA8XX_MSTPRI_UHPI,
  52         DA8XX_MSTPRI_USB1,
  53         DA8XX_MSTPRI_LCDC,
  54 };
  55
  56 struct da8xx_mstpri_descr {
  57         int reg;
  58         int shift;
  59         int mask;
  60 };
  61
  62 static const struct da8xx_mstpri_descr da8xx_mstpri_priority_list[] = {
  63         [DA8XX_MSTPRI_ARM_I] = {
  64                 .reg = DA8XX_MSTPRI0_OFFSET,
  65                 .shift = 0,
  66                 .mask = 0x0000000f,
  67         },
  68         [DA8XX_MSTPRI_ARM_D] = {
  69                 .reg = DA8XX_MSTPRI0_OFFSET,
  70                 .shift = 4,
  71                 .mask = 0x000000f0,
  72         },
  73         [DA8XX_MSTPRI_UPP] = {
  74                 .reg = DA8XX_MSTPRI0_OFFSET,
  75                 .shift = 16,
  76                 .mask = 0x000f0000,
  77         },
  78         [DA8XX_MSTPRI_SATA] = {
  79                 .reg = DA8XX_MSTPRI0_OFFSET,
  80                 .shift = 20,
  81                 .mask = 0x00f00000,
  82         },
  83         [DA8XX_MSTPRI_PRU0] = {
  84                 .reg = DA8XX_MSTPRI1_OFFSET,
  85                 .shift = 0,
  86                 .mask = 0x0000000f,
  87         },
  88         [DA8XX_MSTPRI_PRU1] = {
  89                 .reg = DA8XX_MSTPRI1_OFFSET,
  90                 .shift = 4,
  91                 .mask = 0x000000f0,
  92         },
  93         [DA8XX_MSTPRI_EDMA30TC0] = {
  94                 .reg = DA8XX_MSTPRI1_OFFSET,
  95                 .shift = 8,
  96                 .mask = 0x00000f00,
  97         },
  98         [DA8XX_MSTPRI_EDMA30TC1] = {
  99                 .reg = DA8XX_MSTPRI1_OFFSET,
 100                 .shift = 12,
 101                 .mask = 0x0000f000,
 102         },
 103         [DA8XX_MSTPRI_EDMA31TC0] = {
 104                 .reg = DA8XX_MSTPRI1_OFFSET,
 105                 .shift = 16,
 106                 .mask = 0x000f0000,
 107         },
 108         [DA8XX_MSTPRI_VPIF_DMA_0] = {
 109                 .reg = DA8XX_MSTPRI1_OFFSET,
 110                 .shift = 24,
 111                 .mask = 0x0f000000,
 112         },
 113         [DA8XX_MSTPRI_VPIF_DMA_1] = {
 114                 .reg = DA8XX_MSTPRI1_OFFSET,
 115                 .shift = 28,
 116                 .mask = 0xf0000000,
 117         },
 118         [DA8XX_MSTPRI_EMAC] = {
 119                 .reg = DA8XX_MSTPRI2_OFFSET,
 120                 .shift = 0,
 121                 .mask = 0x0000000f,
 122         },
 123         [DA8XX_MSTPRI_USB0CFG] = {
 124                 .reg = DA8XX_MSTPRI2_OFFSET,
 125                 .shift = 8,
 126                 .mask = 0x00000f00,
 127         },
 128         [DA8XX_MSTPRI_USB0CDMA] = {
 129                 .reg = DA8XX_MSTPRI2_OFFSET,
 130                 .shift = 12,
 131                 .mask = 0x0000f000,
 132         },
 133         [DA8XX_MSTPRI_UHPI] = {
 134                 .reg = DA8XX_MSTPRI2_OFFSET,
 135                 .shift = 20,
 136                 .mask = 0x00f00000,
 137         },
 138         [DA8XX_MSTPRI_USB1] = {
 139                 .reg = DA8XX_MSTPRI2_OFFSET,
 140                 .shift = 24,
 141                 .mask = 0x0f000000,
 142         },
 143         [DA8XX_MSTPRI_LCDC] = {
 144                 .reg = DA8XX_MSTPRI2_OFFSET,
 145                 .shift = 28,
 146                 .mask = 0xf0000000,
 147         },
 148 };
 149
 150 struct da8xx_mstpri_priority {
 151         int which;
 152         u32 val;
 153 };
 154
 155 struct da8xx_mstpri_board_priorities {
 156         const char *board;
 157         const struct da8xx_mstpri_priority *priorities;
 158         size_t numprio;
 159 };
 160
 161 /*
 162  * Default memory settings of da850 do not meet the throughput/latency
 163  * requirements of tilcdc. This results in the image displayed being
 164  * incorrect and the following warning being displayed by the LCDC
 165  * drm driver:
 166  *
 167  *   tilcdc da8xx_lcdc.0: tilcdc_crtc_irq(0x00000020): FIFO underfow
 168  */
 169 static const struct da8xx_mstpri_priority da850_lcdk_priorities[] = {
 170         {
 171                 .which = DA8XX_MSTPRI_LCDC,
 172                 .val = 0,
 173         },
 174         {
 175                 .which = DA8XX_MSTPRI_EDMA30TC1,
 176                 .val = 0,
 177         },
 178         {
 179                 .which = DA8XX_MSTPRI_EDMA30TC0,
 180                 .val = 1,
 181         },
 182 };
 183
 184 static const struct da8xx_mstpri_board_priorities da8xx_mstpri_board_confs[] = {
 185         {
 186                 .board = "ti,da850-lcdk",
 187                 .priorities = da850_lcdk_priorities,
 188                 .numprio = ARRAY_SIZE(da850_lcdk_priorities),
 189         },
 190 };
 191
 192 static const struct da8xx_mstpri_board_priorities *
 193 da8xx_mstpri_get_board_prio(void)
 194 {
 195         const struct da8xx_mstpri_board_priorities *board_prio;
 196         int i;
 197
 198         for (i = 0; i < ARRAY_SIZE(da8xx_mstpri_board_confs); i++) {
 199                 board_prio = &da8xx_mstpri_board_confs[i];
 200
 201                 if (of_machine_is_compatible(board_prio->board))
 202                         return board_prio;
 203         }
 204
 205         return NULL;
 206 }
 207
 208 static int da8xx_mstpri_probe(struct platform_device *pdev)
 209 {
 210         const struct da8xx_mstpri_board_priorities *prio_list;
 211         const struct da8xx_mstpri_descr *prio_descr;
 212         const struct da8xx_mstpri_priority *prio;
 213         struct device *dev = &pdev->dev;
 214         struct resource *res;
 215         void __iomem *mstpri;
 216         u32 reg;
 217         int i;
 218
 219         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 220         mstpri = devm_ioremap_resource(dev, res);
 221         if (IS_ERR(mstpri)) {
 222                 dev_err(dev, "unable to map MSTPRI registers\n");
 223                 return PTR_ERR(mstpri);
 224         }
 225
 226         prio_list = da8xx_mstpri_get_board_prio();
 227         if (!prio_list) {
 228                 dev_err(dev, "no master priorities defined for this board\n");
 229                 return -EINVAL;
 230         }
 231
 232         for (i = 0; i < prio_list->numprio; i++) {
 233                 prio = &prio_list->priorities[i];
 234                 prio_descr = &da8xx_mstpri_priority_list[prio->which];
 235
 236                 if (prio_descr->reg + sizeof(u32) > resource_size(res)) {
 237                         dev_warn(dev, "register offset out of range\n");
 238                         continue;
 239                 }
 240
 241                 reg = readl(mstpri + prio_descr->reg);
 242                 reg &= ~prio_descr->mask;
 243                 reg |= prio->val << prio_descr->shift;
 244
 245                 writel(reg, mstpri + prio_descr->reg);
 246         }
 247
 248         return 0;
 249 }
 250
 251 static const struct of_device_id da8xx_mstpri_of_match[] = {
 252         { .compatible = "ti,da850-mstpri", },
 253         { },
 254 };
 255
 256 static struct platform_driver da8xx_mstpri_driver = {
 257         .probe = da8xx_mstpri_probe,
 258         .driver = {
 259                 .name = "da8xx-mstpri",
 260                 .of_match_table = da8xx_mstpri_of_match,
 261         },
 262 };
 263 module_platform_driver(da8xx_mstpri_driver);
 264
 265 MODULE_AUTHOR("Bartosz Golaszewski <bgolaszewski@baylibre.com>");
 266 MODULE_DESCRIPTION("TI da8xx master peripheral priority driver");
 267 MODULE_LICENSE("GPL v2");