--- zzzz-none-000/linux-3.10.107/drivers/dma/of-dma.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/drivers/dma/of-dma.c 2021-02-04 17:41:59.000000000 +0000 @@ -35,8 +35,7 @@ struct of_dma *ofdma; list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers) - if ((ofdma->of_node == dma_spec->np) && - (ofdma->of_dma_nbcells == dma_spec->args_count)) + if (ofdma->of_node == dma_spec->np) return ofdma; pr_debug("%s: can't find DMA controller %s\n", __func__, @@ -46,6 +45,50 @@ } /** + * of_dma_router_xlate - translation function for router devices + * @dma_spec: pointer to DMA specifier as found in the device tree + * @of_dma: pointer to DMA controller data (router information) + * + * The function creates new dma_spec to be passed to the router driver's + * of_dma_route_allocate() function to prepare a dma_spec which will be used + * to request channel from the real DMA controller. + */ +static struct dma_chan *of_dma_router_xlate(struct of_phandle_args *dma_spec, + struct of_dma *ofdma) +{ + struct dma_chan *chan; + struct of_dma *ofdma_target; + struct of_phandle_args dma_spec_target; + void *route_data; + + /* translate the request for the real DMA controller */ + memcpy(&dma_spec_target, dma_spec, sizeof(dma_spec_target)); + route_data = ofdma->of_dma_route_allocate(&dma_spec_target, ofdma); + if (IS_ERR(route_data)) + return NULL; + + ofdma_target = of_dma_find_controller(&dma_spec_target); + if (!ofdma_target) + return NULL; + + chan = ofdma_target->of_dma_xlate(&dma_spec_target, ofdma_target); + if (chan) { + chan->router = ofdma->dma_router; + chan->route_data = route_data; + } else { + ofdma->dma_router->route_free(ofdma->dma_router->dev, + route_data); + } + + /* + * Need to put the node back since the ofdma->of_dma_route_allocate + * has taken it for generating the new, translated dma_spec + */ + of_node_put(dma_spec_target.np); + return chan; +} + +/** * of_dma_controller_register - Register a DMA controller to DT DMA helpers * @np: device node of DMA controller * @of_dma_xlate: translation function which converts a phandle @@ -64,8 +107,6 @@ void *data) { struct of_dma *ofdma; - int nbcells; - const __be32 *prop; if (!np || !of_dma_xlate) { pr_err("%s: not enough information provided\n", __func__); @@ -76,19 +117,7 @@ if (!ofdma) return -ENOMEM; - prop = of_get_property(np, "#dma-cells", NULL); - if (prop) - nbcells = be32_to_cpup(prop); - - if (!prop || !nbcells) { - pr_err("%s: #dma-cells property is missing or invalid\n", - __func__); - kfree(ofdma); - return -EINVAL; - } - ofdma->of_node = np; - ofdma->of_dma_nbcells = nbcells; ofdma->of_dma_xlate = of_dma_xlate; ofdma->of_dma_data = data; @@ -125,6 +154,51 @@ EXPORT_SYMBOL_GPL(of_dma_controller_free); /** + * of_dma_router_register - Register a DMA router to DT DMA helpers as a + * controller + * @np: device node of DMA router + * @of_dma_route_allocate: setup function for the router which need to + * modify the dma_spec for the DMA controller to + * use and to set up the requested route. + * @dma_router: pointer to dma_router structure to be used when + * the route need to be free up. + * + * Returns 0 on success or appropriate errno value on error. + * + * Allocated memory should be freed with appropriate of_dma_controller_free() + * call. + */ +int of_dma_router_register(struct device_node *np, + void *(*of_dma_route_allocate) + (struct of_phandle_args *, struct of_dma *), + struct dma_router *dma_router) +{ + struct of_dma *ofdma; + + if (!np || !of_dma_route_allocate || !dma_router) { + pr_err("%s: not enough information provided\n", __func__); + return -EINVAL; + } + + ofdma = kzalloc(sizeof(*ofdma), GFP_KERNEL); + if (!ofdma) + return -ENOMEM; + + ofdma->of_node = np; + ofdma->of_dma_xlate = of_dma_router_xlate; + ofdma->of_dma_route_allocate = of_dma_route_allocate; + ofdma->dma_router = dma_router; + + /* Now queue of_dma controller structure in list */ + mutex_lock(&of_dma_lock); + list_add_tail(&ofdma->of_dma_controllers, &of_dma_list); + mutex_unlock(&of_dma_lock); + + return 0; +} +EXPORT_SYMBOL_GPL(of_dma_router_register); + +/** * of_dma_match_channel - Check if a DMA specifier matches name * @np: device node to look for DMA channels * @name: channel name to be matched @@ -158,7 +232,7 @@ * @np: device node to get DMA request from * @name: name of desired channel * - * Returns pointer to appropriate dma channel on success or NULL on error. + * Returns pointer to appropriate DMA channel on success or an error pointer. */ struct dma_chan *of_dma_request_slave_channel(struct device_node *np, const char *name) @@ -167,16 +241,22 @@ struct of_dma *ofdma; struct dma_chan *chan; int count, i; + int ret_no_channel = -ENODEV; if (!np || !name) { pr_err("%s: not enough information provided\n", __func__); - return NULL; + return ERR_PTR(-ENODEV); } + /* Silently fail if there is not even the "dmas" property */ + if (!of_find_property(np, "dmas", NULL)) + return ERR_PTR(-ENODEV); + count = of_property_count_strings(np, "dma-names"); if (count < 0) { - pr_err("%s: dma-names property missing or empty\n", __func__); - return NULL; + pr_err("%s: dma-names property of node '%s' missing or empty\n", + __func__, np->full_name); + return ERR_PTR(-ENODEV); } for (i = 0; i < count; i++) { @@ -186,10 +266,12 @@ mutex_lock(&of_dma_lock); ofdma = of_dma_find_controller(&dma_spec); - if (ofdma) + if (ofdma) { chan = ofdma->of_dma_xlate(&dma_spec, ofdma); - else + } else { + ret_no_channel = -EPROBE_DEFER; chan = NULL; + } mutex_unlock(&of_dma_lock); @@ -199,8 +281,9 @@ return chan; } - return NULL; + return ERR_PTR(ret_no_channel); } +EXPORT_SYMBOL_GPL(of_dma_request_slave_channel); /** * of_dma_simple_xlate - Simple DMA engine translation function @@ -229,3 +312,38 @@ &dma_spec->args[0]); } EXPORT_SYMBOL_GPL(of_dma_simple_xlate); + +/** + * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id + * @dma_spec: pointer to DMA specifier as found in the device tree + * @of_dma: pointer to DMA controller data + * + * This function can be used as the of xlate callback for DMA driver which wants + * to match the channel based on the channel id. When using this xlate function + * the #dma-cells propety of the DMA controller dt node needs to be set to 1. + * The data parameter of of_dma_controller_register must be a pointer to the + * dma_device struct the function should match upon. + * + * Returns pointer to appropriate dma channel on success or NULL on error. + */ +struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec, + struct of_dma *ofdma) +{ + struct dma_device *dev = ofdma->of_dma_data; + struct dma_chan *chan, *candidate = NULL; + + if (!dev || dma_spec->args_count != 1) + return NULL; + + list_for_each_entry(chan, &dev->channels, device_node) + if (chan->chan_id == dma_spec->args[0]) { + candidate = chan; + break; + } + + if (!candidate) + return NULL; + + return dma_get_slave_channel(candidate); +} +EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);