Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 1 | /* |
| 2 | * Device tree helpers for DMA request / controller |
| 3 | * |
| 4 | * Based on of_gpio.c |
| 5 | * |
| 6 | * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/ |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License version 2 as |
| 10 | * published by the Free Software Foundation. |
| 11 | */ |
| 12 | |
| 13 | #include <linux/device.h> |
| 14 | #include <linux/err.h> |
| 15 | #include <linux/module.h> |
Lars-Peter Clausen | de61608 | 2013-04-19 11:42:14 +0200 | [diff] [blame] | 16 | #include <linux/mutex.h> |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 17 | #include <linux/slab.h> |
| 18 | #include <linux/of.h> |
| 19 | #include <linux/of_dma.h> |
| 20 | |
| 21 | static LIST_HEAD(of_dma_list); |
Lars-Peter Clausen | de61608 | 2013-04-19 11:42:14 +0200 | [diff] [blame] | 22 | static DEFINE_MUTEX(of_dma_lock); |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 23 | |
| 24 | /** |
Lars-Peter Clausen | de61608 | 2013-04-19 11:42:14 +0200 | [diff] [blame] | 25 | * of_dma_find_controller - Get a DMA controller in DT DMA helpers list |
Jon Hunter | 9743a3b | 2012-10-11 14:43:01 -0500 | [diff] [blame] | 26 | * @dma_spec: pointer to DMA specifier as found in the device tree |
| 27 | * |
| 28 | * Finds a DMA controller with matching device node and number for dma cells |
Lars-Peter Clausen | de61608 | 2013-04-19 11:42:14 +0200 | [diff] [blame] | 29 | * in a list of registered DMA controllers. If a match is found a valid pointer |
| 30 | * to the DMA data stored is retuned. A NULL pointer is returned if no match is |
| 31 | * found. |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 32 | */ |
Lars-Peter Clausen | de61608 | 2013-04-19 11:42:14 +0200 | [diff] [blame] | 33 | static struct of_dma *of_dma_find_controller(struct of_phandle_args *dma_spec) |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 34 | { |
| 35 | struct of_dma *ofdma; |
| 36 | |
Jon Hunter | 9743a3b | 2012-10-11 14:43:01 -0500 | [diff] [blame] | 37 | list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers) |
Lars-Peter Clausen | 8552bb4 | 2013-04-22 10:33:33 +0200 | [diff] [blame] | 38 | if (ofdma->of_node == dma_spec->np) |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 39 | return ofdma; |
Jon Hunter | 9743a3b | 2012-10-11 14:43:01 -0500 | [diff] [blame] | 40 | |
| 41 | pr_debug("%s: can't find DMA controller %s\n", __func__, |
| 42 | dma_spec->np->full_name); |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 43 | |
| 44 | return NULL; |
| 45 | } |
| 46 | |
| 47 | /** |
| 48 | * of_dma_controller_register - Register a DMA controller to DT DMA helpers |
| 49 | * @np: device node of DMA controller |
| 50 | * @of_dma_xlate: translation function which converts a phandle |
| 51 | * arguments list into a dma_chan structure |
| 52 | * @data pointer to controller specific data to be used by |
| 53 | * translation function |
| 54 | * |
| 55 | * Returns 0 on success or appropriate errno value on error. |
| 56 | * |
| 57 | * Allocated memory should be freed with appropriate of_dma_controller_free() |
| 58 | * call. |
| 59 | */ |
| 60 | int of_dma_controller_register(struct device_node *np, |
| 61 | struct dma_chan *(*of_dma_xlate) |
| 62 | (struct of_phandle_args *, struct of_dma *), |
| 63 | void *data) |
| 64 | { |
| 65 | struct of_dma *ofdma; |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 66 | |
| 67 | if (!np || !of_dma_xlate) { |
| 68 | pr_err("%s: not enough information provided\n", __func__); |
| 69 | return -EINVAL; |
| 70 | } |
| 71 | |
| 72 | ofdma = kzalloc(sizeof(*ofdma), GFP_KERNEL); |
| 73 | if (!ofdma) |
| 74 | return -ENOMEM; |
| 75 | |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 76 | ofdma->of_node = np; |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 77 | ofdma->of_dma_xlate = of_dma_xlate; |
| 78 | ofdma->of_dma_data = data; |
| 79 | |
| 80 | /* Now queue of_dma controller structure in list */ |
Lars-Peter Clausen | de61608 | 2013-04-19 11:42:14 +0200 | [diff] [blame] | 81 | mutex_lock(&of_dma_lock); |
Jon Hunter | 9743a3b | 2012-10-11 14:43:01 -0500 | [diff] [blame] | 82 | list_add_tail(&ofdma->of_dma_controllers, &of_dma_list); |
Lars-Peter Clausen | de61608 | 2013-04-19 11:42:14 +0200 | [diff] [blame] | 83 | mutex_unlock(&of_dma_lock); |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 84 | |
| 85 | return 0; |
| 86 | } |
| 87 | EXPORT_SYMBOL_GPL(of_dma_controller_register); |
| 88 | |
| 89 | /** |
| 90 | * of_dma_controller_free - Remove a DMA controller from DT DMA helpers list |
| 91 | * @np: device node of DMA controller |
| 92 | * |
| 93 | * Memory allocated by of_dma_controller_register() is freed here. |
| 94 | */ |
Lars-Peter Clausen | de61608 | 2013-04-19 11:42:14 +0200 | [diff] [blame] | 95 | void of_dma_controller_free(struct device_node *np) |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 96 | { |
| 97 | struct of_dma *ofdma; |
| 98 | |
Lars-Peter Clausen | de61608 | 2013-04-19 11:42:14 +0200 | [diff] [blame] | 99 | mutex_lock(&of_dma_lock); |
Jon Hunter | 9743a3b | 2012-10-11 14:43:01 -0500 | [diff] [blame] | 100 | |
| 101 | list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers) |
| 102 | if (ofdma->of_node == np) { |
Jon Hunter | 9743a3b | 2012-10-11 14:43:01 -0500 | [diff] [blame] | 103 | list_del(&ofdma->of_dma_controllers); |
Jon Hunter | 9743a3b | 2012-10-11 14:43:01 -0500 | [diff] [blame] | 104 | kfree(ofdma); |
Lars-Peter Clausen | de61608 | 2013-04-19 11:42:14 +0200 | [diff] [blame] | 105 | break; |
Jon Hunter | 9743a3b | 2012-10-11 14:43:01 -0500 | [diff] [blame] | 106 | } |
| 107 | |
Lars-Peter Clausen | de61608 | 2013-04-19 11:42:14 +0200 | [diff] [blame] | 108 | mutex_unlock(&of_dma_lock); |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 109 | } |
| 110 | EXPORT_SYMBOL_GPL(of_dma_controller_free); |
| 111 | |
| 112 | /** |
Jon Hunter | 5ca7c10 | 2012-09-25 13:59:31 -0500 | [diff] [blame] | 113 | * of_dma_match_channel - Check if a DMA specifier matches name |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 114 | * @np: device node to look for DMA channels |
Jon Hunter | 5ca7c10 | 2012-09-25 13:59:31 -0500 | [diff] [blame] | 115 | * @name: channel name to be matched |
| 116 | * @index: index of DMA specifier in list of DMA specifiers |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 117 | * @dma_spec: pointer to DMA specifier as found in the device tree |
| 118 | * |
Jon Hunter | 5ca7c10 | 2012-09-25 13:59:31 -0500 | [diff] [blame] | 119 | * Check if the DMA specifier pointed to by the index in a list of DMA |
| 120 | * specifiers, matches the name provided. Returns 0 if the name matches and |
| 121 | * a valid pointer to the DMA specifier is found. Otherwise returns -ENODEV. |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 122 | */ |
Markus Pargmann | bef29ec | 2013-02-24 16:36:09 +0100 | [diff] [blame] | 123 | static int of_dma_match_channel(struct device_node *np, const char *name, |
| 124 | int index, struct of_phandle_args *dma_spec) |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 125 | { |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 126 | const char *s; |
| 127 | |
Jon Hunter | 5ca7c10 | 2012-09-25 13:59:31 -0500 | [diff] [blame] | 128 | if (of_property_read_string_index(np, "dma-names", index, &s)) |
| 129 | return -ENODEV; |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 130 | |
Jon Hunter | 5ca7c10 | 2012-09-25 13:59:31 -0500 | [diff] [blame] | 131 | if (strcmp(name, s)) |
| 132 | return -ENODEV; |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 133 | |
Jon Hunter | 5ca7c10 | 2012-09-25 13:59:31 -0500 | [diff] [blame] | 134 | if (of_parse_phandle_with_args(np, "dmas", "#dma-cells", index, |
| 135 | dma_spec)) |
| 136 | return -ENODEV; |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 137 | |
Jon Hunter | 5ca7c10 | 2012-09-25 13:59:31 -0500 | [diff] [blame] | 138 | return 0; |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 139 | } |
| 140 | |
| 141 | /** |
| 142 | * of_dma_request_slave_channel - Get the DMA slave channel |
| 143 | * @np: device node to get DMA request from |
| 144 | * @name: name of desired channel |
| 145 | * |
Stephen Warren | 0ad7c00 | 2013-11-26 10:04:22 -0700 | [diff] [blame] | 146 | * Returns pointer to appropriate DMA channel on success or an error pointer. |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 147 | */ |
| 148 | struct dma_chan *of_dma_request_slave_channel(struct device_node *np, |
Markus Pargmann | bef29ec | 2013-02-24 16:36:09 +0100 | [diff] [blame] | 149 | const char *name) |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 150 | { |
| 151 | struct of_phandle_args dma_spec; |
| 152 | struct of_dma *ofdma; |
| 153 | struct dma_chan *chan; |
Jon Hunter | 5ca7c10 | 2012-09-25 13:59:31 -0500 | [diff] [blame] | 154 | int count, i; |
Stephen Warren | 0ad7c00 | 2013-11-26 10:04:22 -0700 | [diff] [blame] | 155 | int ret_no_channel = -ENODEV; |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 156 | |
| 157 | if (!np || !name) { |
| 158 | pr_err("%s: not enough information provided\n", __func__); |
Stephen Warren | 0ad7c00 | 2013-11-26 10:04:22 -0700 | [diff] [blame] | 159 | return ERR_PTR(-ENODEV); |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 160 | } |
| 161 | |
Jon Hunter | 5ca7c10 | 2012-09-25 13:59:31 -0500 | [diff] [blame] | 162 | count = of_property_count_strings(np, "dma-names"); |
| 163 | if (count < 0) { |
Lothar Waßmann | 303fd71 | 2013-07-31 16:14:35 +0200 | [diff] [blame] | 164 | pr_err("%s: dma-names property of node '%s' missing or empty\n", |
| 165 | __func__, np->full_name); |
Stephen Warren | 0ad7c00 | 2013-11-26 10:04:22 -0700 | [diff] [blame] | 166 | return ERR_PTR(-ENODEV); |
Jon Hunter | 5ca7c10 | 2012-09-25 13:59:31 -0500 | [diff] [blame] | 167 | } |
| 168 | |
| 169 | for (i = 0; i < count; i++) { |
| 170 | if (of_dma_match_channel(np, name, i, &dma_spec)) |
| 171 | continue; |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 172 | |
Lars-Peter Clausen | de61608 | 2013-04-19 11:42:14 +0200 | [diff] [blame] | 173 | mutex_lock(&of_dma_lock); |
| 174 | ofdma = of_dma_find_controller(&dma_spec); |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 175 | |
Stephen Warren | 0ad7c00 | 2013-11-26 10:04:22 -0700 | [diff] [blame] | 176 | if (ofdma) { |
Lars-Peter Clausen | f22eb14 | 2013-04-19 11:42:13 +0200 | [diff] [blame] | 177 | chan = ofdma->of_dma_xlate(&dma_spec, ofdma); |
Stephen Warren | 0ad7c00 | 2013-11-26 10:04:22 -0700 | [diff] [blame] | 178 | } else { |
| 179 | ret_no_channel = -EPROBE_DEFER; |
Lars-Peter Clausen | f22eb14 | 2013-04-19 11:42:13 +0200 | [diff] [blame] | 180 | chan = NULL; |
Stephen Warren | 0ad7c00 | 2013-11-26 10:04:22 -0700 | [diff] [blame] | 181 | } |
Lars-Peter Clausen | de61608 | 2013-04-19 11:42:14 +0200 | [diff] [blame] | 182 | |
| 183 | mutex_unlock(&of_dma_lock); |
Jon Hunter | 9743a3b | 2012-10-11 14:43:01 -0500 | [diff] [blame] | 184 | |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 185 | of_node_put(dma_spec.np); |
| 186 | |
Jon Hunter | 5ca7c10 | 2012-09-25 13:59:31 -0500 | [diff] [blame] | 187 | if (chan) |
| 188 | return chan; |
| 189 | } |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 190 | |
Stephen Warren | 0ad7c00 | 2013-11-26 10:04:22 -0700 | [diff] [blame] | 191 | return ERR_PTR(ret_no_channel); |
Jon Hunter | aa3da64 | 2012-09-14 17:41:56 -0500 | [diff] [blame] | 192 | } |
| 193 | |
| 194 | /** |
| 195 | * of_dma_simple_xlate - Simple DMA engine translation function |
| 196 | * @dma_spec: pointer to DMA specifier as found in the device tree |
| 197 | * @of_dma: pointer to DMA controller data |
| 198 | * |
| 199 | * A simple translation function for devices that use a 32-bit value for the |
| 200 | * filter_param when calling the DMA engine dma_request_channel() function. |
| 201 | * Note that this translation function requires that #dma-cells is equal to 1 |
| 202 | * and the argument of the dma specifier is the 32-bit filter_param. Returns |
| 203 | * pointer to appropriate dma channel on success or NULL on error. |
| 204 | */ |
| 205 | struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec, |
| 206 | struct of_dma *ofdma) |
| 207 | { |
| 208 | int count = dma_spec->args_count; |
| 209 | struct of_dma_filter_info *info = ofdma->of_dma_data; |
| 210 | |
| 211 | if (!info || !info->filter_fn) |
| 212 | return NULL; |
| 213 | |
| 214 | if (count != 1) |
| 215 | return NULL; |
| 216 | |
| 217 | return dma_request_channel(info->dma_cap, info->filter_fn, |
| 218 | &dma_spec->args[0]); |
| 219 | } |
| 220 | EXPORT_SYMBOL_GPL(of_dma_simple_xlate); |
Alexander Popov | 16369ef | 2014-06-25 14:52:59 +0400 | [diff] [blame^] | 221 | |
| 222 | /** |
| 223 | * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id |
| 224 | * @dma_spec: pointer to DMA specifier as found in the device tree |
| 225 | * @of_dma: pointer to DMA controller data |
| 226 | * |
| 227 | * This function can be used as the of xlate callback for DMA driver which wants |
| 228 | * to match the channel based on the channel id. When using this xlate function |
| 229 | * the #dma-cells propety of the DMA controller dt node needs to be set to 1. |
| 230 | * The data parameter of of_dma_controller_register must be a pointer to the |
| 231 | * dma_device struct the function should match upon. |
| 232 | * |
| 233 | * Returns pointer to appropriate dma channel on success or NULL on error. |
| 234 | */ |
| 235 | struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec, |
| 236 | struct of_dma *ofdma) |
| 237 | { |
| 238 | struct dma_device *dev = ofdma->of_dma_data; |
| 239 | struct dma_chan *chan, *candidate = NULL; |
| 240 | |
| 241 | if (!dev || dma_spec->args_count != 1) |
| 242 | return NULL; |
| 243 | |
| 244 | list_for_each_entry(chan, &dev->channels, device_node) |
| 245 | if (chan->chan_id == dma_spec->args[0]) { |
| 246 | candidate = chan; |
| 247 | break; |
| 248 | } |
| 249 | |
| 250 | if (!candidate) |
| 251 | return NULL; |
| 252 | |
| 253 | return dma_get_slave_channel(candidate); |
| 254 | } |
| 255 | EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id); |