drivers/bus/da8xx-mstpri.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * TI da8xx master peripheral priority driver
   4  *
   5  * Copyright (C) 2016 BayLibre SAS
   6  *
   7  * Author:
   8  *   Bartosz Golaszewski <bgolaszewski@baylibre.com>
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/of.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/io.h>
  15 #include <linux/regmap.h>
  16
  17 /*
  18  * REVISIT: Linux doesn't have a good framework for the kind of performance
  19  * knobs this driver controls. We can't use device tree properties as it deals
  20  * with hardware configuration rather than description. We also don't want to
  21  * commit to maintaining some random sysfs attributes.
  22  *
  23  * For now we just hardcode the register values for the boards that need
  24  * some changes (as is the case for the LCD controller on da850-lcdk - the
  25  * first board we support here). When linux gets an appropriate framework,
  26  * we'll easily convert the driver to it.
  27  */
  28
  29 #define DA8XX_MSTPRI0_OFFSET            0
  30 #define DA8XX_MSTPRI1_OFFSET            4
  31 #define DA8XX_MSTPRI2_OFFSET            8
  32
  33 enum {
  34         DA8XX_MSTPRI_ARM_I = 0,
  35         DA8XX_MSTPRI_ARM_D,
  36         DA8XX_MSTPRI_UPP,
  37         DA8XX_MSTPRI_SATA,
  38         DA8XX_MSTPRI_PRU0,
  39         DA8XX_MSTPRI_PRU1,
  40         DA8XX_MSTPRI_EDMA30TC0,
  41         DA8XX_MSTPRI_EDMA30TC1,
  42         DA8XX_MSTPRI_EDMA31TC0,
  43         DA8XX_MSTPRI_VPIF_DMA_0,
  44         DA8XX_MSTPRI_VPIF_DMA_1,
  45         DA8XX_MSTPRI_EMAC,
  46         DA8XX_MSTPRI_USB0CFG,
  47         DA8XX_MSTPRI_USB0CDMA,
  48         DA8XX_MSTPRI_UHPI,
  49         DA8XX_MSTPRI_USB1,
  50         DA8XX_MSTPRI_LCDC,
  51 };
  52
  53 struct da8xx_mstpri_descr {
  54         int reg;
  55         int shift;
  56         int mask;
  57 };
  58
  59 static const struct da8xx_mstpri_descr da8xx_mstpri_priority_list[] = {
  60         [DA8XX_MSTPRI_ARM_I] = {
  61                 .reg = DA8XX_MSTPRI0_OFFSET,
  62                 .shift = 0,
  63                 .mask = 0x0000000f,
  64         },
  65         [DA8XX_MSTPRI_ARM_D] = {
  66                 .reg = DA8XX_MSTPRI0_OFFSET,
  67                 .shift = 4,
  68                 .mask = 0x000000f0,
  69         },
  70         [DA8XX_MSTPRI_UPP] = {
  71                 .reg = DA8XX_MSTPRI0_OFFSET,
  72                 .shift = 16,
  73                 .mask = 0x000f0000,
  74         },
  75         [DA8XX_MSTPRI_SATA] = {
  76                 .reg = DA8XX_MSTPRI0_OFFSET,
  77                 .shift = 20,
  78                 .mask = 0x00f00000,
  79         },
  80         [DA8XX_MSTPRI_PRU0] = {
  81                 .reg = DA8XX_MSTPRI1_OFFSET,
  82                 .shift = 0,
  83                 .mask = 0x0000000f,
  84         },
  85         [DA8XX_MSTPRI_PRU1] = {
  86                 .reg = DA8XX_MSTPRI1_OFFSET,
  87                 .shift = 4,
  88                 .mask = 0x000000f0,
  89         },
  90         [DA8XX_MSTPRI_EDMA30TC0] = {
  91                 .reg = DA8XX_MSTPRI1_OFFSET,
  92                 .shift = 8,
  93                 .mask = 0x00000f00,
  94         },
  95         [DA8XX_MSTPRI_EDMA30TC1] = {
  96                 .reg = DA8XX_MSTPRI1_OFFSET,
  97                 .shift = 12,
  98                 .mask = 0x0000f000,
  99         },
 100         [DA8XX_MSTPRI_EDMA31TC0] = {
 101                 .reg = DA8XX_MSTPRI1_OFFSET,
 102                 .shift = 16,
 103                 .mask = 0x000f0000,
 104         },
 105         [DA8XX_MSTPRI_VPIF_DMA_0] = {
 106                 .reg = DA8XX_MSTPRI1_OFFSET,
 107                 .shift = 24,
 108                 .mask = 0x0f000000,
 109         },
 110         [DA8XX_MSTPRI_VPIF_DMA_1] = {
 111                 .reg = DA8XX_MSTPRI1_OFFSET,
 112                 .shift = 28,
 113                 .mask = 0xf0000000,
 114         },
 115         [DA8XX_MSTPRI_EMAC] = {
 116                 .reg = DA8XX_MSTPRI2_OFFSET,
 117                 .shift = 0,
 118                 .mask = 0x0000000f,
 119         },
 120         [DA8XX_MSTPRI_USB0CFG] = {
 121                 .reg = DA8XX_MSTPRI2_OFFSET,
 122                 .shift = 8,
 123                 .mask = 0x00000f00,
 124         },
 125         [DA8XX_MSTPRI_USB0CDMA] = {
 126                 .reg = DA8XX_MSTPRI2_OFFSET,
 127                 .shift = 12,
 128                 .mask = 0x0000f000,
 129         },
 130         [DA8XX_MSTPRI_UHPI] = {
 131                 .reg = DA8XX_MSTPRI2_OFFSET,
 132                 .shift = 20,
 133                 .mask = 0x00f00000,
 134         },
 135         [DA8XX_MSTPRI_USB1] = {
 136                 .reg = DA8XX_MSTPRI2_OFFSET,
 137                 .shift = 24,
 138                 .mask = 0x0f000000,
 139         },
 140         [DA8XX_MSTPRI_LCDC] = {
 141                 .reg = DA8XX_MSTPRI2_OFFSET,
 142                 .shift = 28,
 143                 .mask = 0xf0000000,
 144         },
 145 };
 146
 147 struct da8xx_mstpri_priority {
 148         int which;
 149         u32 val;
 150 };
 151
 152 struct da8xx_mstpri_board_priorities {
 153         const char *board;
 154         const struct da8xx_mstpri_priority *priorities;
 155         size_t numprio;
 156 };
 157
 158 /*
 159  * Default memory settings of da850 do not meet the throughput/latency
 160  * requirements of tilcdc. This results in the image displayed being
 161  * incorrect and the following warning being displayed by the LCDC
 162  * drm driver:
 163  *
 164  *   tilcdc da8xx_lcdc.0: tilcdc_crtc_irq(0x00000020): FIFO underfow
 165  */
 166 static const struct da8xx_mstpri_priority da850_lcdk_priorities[] = {
 167         {
 168                 .which = DA8XX_MSTPRI_LCDC,
 169                 .val = 0,
 170         },
 171         {
 172                 .which = DA8XX_MSTPRI_EDMA30TC1,
 173                 .val = 0,
 174         },
 175         {
 176                 .which = DA8XX_MSTPRI_EDMA30TC0,
 177                 .val = 1,
 178         },
 179 };
 180
 181 static const struct da8xx_mstpri_board_priorities da8xx_mstpri_board_confs[] = {
 182         {
 183                 .board = "ti,da850-lcdk",
 184                 .priorities = da850_lcdk_priorities,
 185                 .numprio = ARRAY_SIZE(da850_lcdk_priorities),
 186         },
 187 };
 188
 189 static const struct da8xx_mstpri_board_priorities *
 190 da8xx_mstpri_get_board_prio(void)
 191 {
 192         const struct da8xx_mstpri_board_priorities *board_prio;
 193         int i;
 194
 195         for (i = 0; i < ARRAY_SIZE(da8xx_mstpri_board_confs); i++) {
 196                 board_prio = &da8xx_mstpri_board_confs[i];
 197
 198                 if (of_machine_is_compatible(board_prio->board))
 199                         return board_prio;
 200         }
 201
 202         return NULL;
 203 }
 204
 205 static int da8xx_mstpri_probe(struct platform_device *pdev)
 206 {
 207         const struct da8xx_mstpri_board_priorities *prio_list;
 208         const struct da8xx_mstpri_descr *prio_descr;
 209         const struct da8xx_mstpri_priority *prio;
 210         struct device *dev = &pdev->dev;
 211         struct resource *res;
 212         void __iomem *mstpri;
 213         u32 reg;
 214         int i;
 215
 216         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 217         mstpri = devm_ioremap_resource(dev, res);
 218         if (IS_ERR(mstpri)) {
 219                 dev_err(dev, "unable to map MSTPRI registers\n");
 220                 return PTR_ERR(mstpri);
 221         }
 222
 223         prio_list = da8xx_mstpri_get_board_prio();
 224         if (!prio_list) {
 225                 dev_err(dev, "no master priorities defined for this board\n");
 226                 return -EINVAL;
 227         }
 228
 229         for (i = 0; i < prio_list->numprio; i++) {
 230                 prio = &prio_list->priorities[i];
 231                 prio_descr = &da8xx_mstpri_priority_list[prio->which];
 232
 233                 if (prio_descr->reg + sizeof(u32) > resource_size(res)) {
 234                         dev_warn(dev, "register offset out of range\n");
 235                         continue;
 236                 }
 237
 238                 reg = readl(mstpri + prio_descr->reg);
 239                 reg &= ~prio_descr->mask;
 240                 reg |= prio->val << prio_descr->shift;
 241
 242                 writel(reg, mstpri + prio_descr->reg);
 243         }
 244
 245         return 0;
 246 }
 247
 248 static const struct of_device_id da8xx_mstpri_of_match[] = {
 249         { .compatible = "ti,da850-mstpri", },
 250         { },
 251 };
 252
 253 static struct platform_driver da8xx_mstpri_driver = {
 254         .probe = da8xx_mstpri_probe,
 255         .driver = {
 256                 .name = "da8xx-mstpri",
 257                 .of_match_table = da8xx_mstpri_of_match,
 258         },
 259 };
 260 module_platform_driver(da8xx_mstpri_driver);
 261
 262 MODULE_AUTHOR("Bartosz Golaszewski <bgolaszewski@baylibre.com>");
 263 MODULE_DESCRIPTION("TI da8xx master peripheral priority driver");
 264 MODULE_LICENSE("GPL v2");