lpc18xx-dmamux.c 4.7 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * DMA Router driver for LPC18xx/43xx DMA MUX
  4. *
  5. * Copyright (C) 2015 Joachim Eastwood <[email protected]>
  6. *
  7. * Based on TI DMA Crossbar driver by:
  8. * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
  9. * Author: Peter Ujfalusi <[email protected]>
  10. */
  11. #include <linux/err.h>
  12. #include <linux/init.h>
  13. #include <linux/mfd/syscon.h>
  14. #include <linux/of_device.h>
  15. #include <linux/of_dma.h>
  16. #include <linux/regmap.h>
  17. #include <linux/spinlock.h>
  18. /* CREG register offset and macros for mux manipulation */
  19. #define LPC18XX_CREG_DMAMUX 0x11c
  20. #define LPC18XX_DMAMUX_VAL(v, n) ((v) << (n * 2))
  21. #define LPC18XX_DMAMUX_MASK(n) (0x3 << (n * 2))
  22. #define LPC18XX_DMAMUX_MAX_VAL 0x3
  23. struct lpc18xx_dmamux {
  24. u32 value;
  25. bool busy;
  26. };
  27. struct lpc18xx_dmamux_data {
  28. struct dma_router dmarouter;
  29. struct lpc18xx_dmamux *muxes;
  30. u32 dma_master_requests;
  31. u32 dma_mux_requests;
  32. struct regmap *reg;
  33. spinlock_t lock;
  34. };
  35. static void lpc18xx_dmamux_free(struct device *dev, void *route_data)
  36. {
  37. struct lpc18xx_dmamux_data *dmamux = dev_get_drvdata(dev);
  38. struct lpc18xx_dmamux *mux = route_data;
  39. unsigned long flags;
  40. spin_lock_irqsave(&dmamux->lock, flags);
  41. mux->busy = false;
  42. spin_unlock_irqrestore(&dmamux->lock, flags);
  43. }
  44. static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec,
  45. struct of_dma *ofdma)
  46. {
  47. struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
  48. struct lpc18xx_dmamux_data *dmamux = platform_get_drvdata(pdev);
  49. unsigned long flags;
  50. unsigned mux;
  51. if (dma_spec->args_count != 3) {
  52. dev_err(&pdev->dev, "invalid number of dma mux args\n");
  53. return ERR_PTR(-EINVAL);
  54. }
  55. mux = dma_spec->args[0];
  56. if (mux >= dmamux->dma_master_requests) {
  57. dev_err(&pdev->dev, "invalid mux number: %d\n",
  58. dma_spec->args[0]);
  59. return ERR_PTR(-EINVAL);
  60. }
  61. if (dma_spec->args[1] > LPC18XX_DMAMUX_MAX_VAL) {
  62. dev_err(&pdev->dev, "invalid dma mux value: %d\n",
  63. dma_spec->args[1]);
  64. return ERR_PTR(-EINVAL);
  65. }
  66. /* The of_node_put() will be done in the core for the node */
  67. dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0);
  68. if (!dma_spec->np) {
  69. dev_err(&pdev->dev, "can't get dma master\n");
  70. return ERR_PTR(-EINVAL);
  71. }
  72. spin_lock_irqsave(&dmamux->lock, flags);
  73. if (dmamux->muxes[mux].busy) {
  74. spin_unlock_irqrestore(&dmamux->lock, flags);
  75. dev_err(&pdev->dev, "dma request %u busy with %u.%u\n",
  76. mux, mux, dmamux->muxes[mux].value);
  77. of_node_put(dma_spec->np);
  78. return ERR_PTR(-EBUSY);
  79. }
  80. dmamux->muxes[mux].busy = true;
  81. dmamux->muxes[mux].value = dma_spec->args[1];
  82. regmap_update_bits(dmamux->reg, LPC18XX_CREG_DMAMUX,
  83. LPC18XX_DMAMUX_MASK(mux),
  84. LPC18XX_DMAMUX_VAL(dmamux->muxes[mux].value, mux));
  85. spin_unlock_irqrestore(&dmamux->lock, flags);
  86. dma_spec->args[1] = dma_spec->args[2];
  87. dma_spec->args_count = 2;
  88. dev_dbg(&pdev->dev, "mapping dmamux %u.%u to dma request %u\n", mux,
  89. dmamux->muxes[mux].value, mux);
  90. return &dmamux->muxes[mux];
  91. }
  92. static int lpc18xx_dmamux_probe(struct platform_device *pdev)
  93. {
  94. struct device_node *dma_np, *np = pdev->dev.of_node;
  95. struct lpc18xx_dmamux_data *dmamux;
  96. int ret;
  97. dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);
  98. if (!dmamux)
  99. return -ENOMEM;
  100. dmamux->reg = syscon_regmap_lookup_by_compatible("nxp,lpc1850-creg");
  101. if (IS_ERR(dmamux->reg)) {
  102. dev_err(&pdev->dev, "syscon lookup failed\n");
  103. return PTR_ERR(dmamux->reg);
  104. }
  105. ret = of_property_read_u32(np, "dma-requests",
  106. &dmamux->dma_mux_requests);
  107. if (ret) {
  108. dev_err(&pdev->dev, "missing dma-requests property\n");
  109. return ret;
  110. }
  111. dma_np = of_parse_phandle(np, "dma-masters", 0);
  112. if (!dma_np) {
  113. dev_err(&pdev->dev, "can't get dma master\n");
  114. return -ENODEV;
  115. }
  116. ret = of_property_read_u32(dma_np, "dma-requests",
  117. &dmamux->dma_master_requests);
  118. of_node_put(dma_np);
  119. if (ret) {
  120. dev_err(&pdev->dev, "missing master dma-requests property\n");
  121. return ret;
  122. }
  123. dmamux->muxes = devm_kcalloc(&pdev->dev, dmamux->dma_master_requests,
  124. sizeof(struct lpc18xx_dmamux),
  125. GFP_KERNEL);
  126. if (!dmamux->muxes)
  127. return -ENOMEM;
  128. spin_lock_init(&dmamux->lock);
  129. platform_set_drvdata(pdev, dmamux);
  130. dmamux->dmarouter.dev = &pdev->dev;
  131. dmamux->dmarouter.route_free = lpc18xx_dmamux_free;
  132. return of_dma_router_register(np, lpc18xx_dmamux_reserve,
  133. &dmamux->dmarouter);
  134. }
  135. static const struct of_device_id lpc18xx_dmamux_match[] = {
  136. { .compatible = "nxp,lpc1850-dmamux" },
  137. {},
  138. };
  139. static struct platform_driver lpc18xx_dmamux_driver = {
  140. .probe = lpc18xx_dmamux_probe,
  141. .driver = {
  142. .name = "lpc18xx-dmamux",
  143. .of_match_table = lpc18xx_dmamux_match,
  144. },
  145. };
  146. static int __init lpc18xx_dmamux_init(void)
  147. {
  148. return platform_driver_register(&lpc18xx_dmamux_driver);
  149. }
  150. arch_initcall(lpc18xx_dmamux_init);