drivers/fpga/of-fpga-region.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * FPGA Region - Device Tree support for FPGA programming under Linux
0004  *
0005  *  Copyright (C) 2013-2016 Altera Corporation
0006  *  Copyright (C) 2017 Intel Corporation
0007  */
0008 #include <linux/fpga/fpga-bridge.h>
0009 #include <linux/fpga/fpga-mgr.h>
0010 #include <linux/fpga/fpga-region.h>
0011 #include <linux/idr.h>
0012 #include <linux/kernel.h>
0013 #include <linux/list.h>
0014 #include <linux/module.h>
0015 #include <linux/of_platform.h>
0016 #include <linux/slab.h>
0017 #include <linux/spinlock.h>
0018
0019 static const struct of_device_id fpga_region_of_match[] = {
0020     { .compatible = "fpga-region", },
0021     {},
0022 };
0023 MODULE_DEVICE_TABLE(of, fpga_region_of_match);
0024
0025 /**
0026  * of_fpga_region_find - find FPGA region
0027  * @np: device node of FPGA Region
0028  *
0029  * Caller will need to put_device(&region->dev) when done.
0030  *
0031  * Return: FPGA Region struct or NULL
0032  */
0033 static struct fpga_region *of_fpga_region_find(struct device_node *np)
0034 {
0035     return fpga_region_class_find(NULL, np, device_match_of_node);
0036 }
0037
0038 /**
0039  * of_fpga_region_get_mgr - get reference for FPGA manager
0040  * @np: device node of FPGA region
0041  *
0042  * Get FPGA Manager from "fpga-mgr" property or from ancestor region.
0043  *
0044  * Caller should call fpga_mgr_put() when done with manager.
0045  *
0046  * Return: fpga manager struct or IS_ERR() condition containing error code.
0047  */
0048 static struct fpga_manager *of_fpga_region_get_mgr(struct device_node *np)
0049 {
0050     struct device_node  *mgr_node;
0051     struct fpga_manager *mgr;
0052
0053     of_node_get(np);
0054     while (np) {
0055         if (of_device_is_compatible(np, "fpga-region")) {
0056             mgr_node = of_parse_phandle(np, "fpga-mgr", 0);
0057             if (mgr_node) {
0058                 mgr = of_fpga_mgr_get(mgr_node);
0059                 of_node_put(mgr_node);
0060                 of_node_put(np);
0061                 return mgr;
0062             }
0063         }
0064         np = of_get_next_parent(np);
0065     }
0066     of_node_put(np);
0067
0068     return ERR_PTR(-EINVAL);
0069 }
0070
0071 /**
0072  * of_fpga_region_get_bridges - create a list of bridges
0073  * @region: FPGA region
0074  *
0075  * Create a list of bridges including the parent bridge and the bridges
0076  * specified by "fpga-bridges" property.  Note that the
0077  * fpga_bridges_enable/disable/put functions are all fine with an empty list
0078  * if that happens.
0079  *
0080  * Caller should call fpga_bridges_put(&region->bridge_list) when
0081  * done with the bridges.
0082  *
0083  * Return: 0 for success (even if there are no bridges specified)
0084  * or -EBUSY if any of the bridges are in use.
0085  */
0086 static int of_fpga_region_get_bridges(struct fpga_region *region)
0087 {
0088     struct device *dev = &region->dev;
0089     struct device_node *region_np = dev->of_node;
0090     struct fpga_image_info *info = region->info;
0091     struct device_node *br, *np, *parent_br = NULL;
0092     int i, ret;
0093
0094     /* If parent is a bridge, add to list */
0095     ret = of_fpga_bridge_get_to_list(region_np->parent, info,
0096                      &region->bridge_list);
0097
0098     /* -EBUSY means parent is a bridge that is under use. Give up. */
0099     if (ret == -EBUSY)
0100         return ret;
0101
0102     /* Zero return code means parent was a bridge and was added to list. */
0103     if (!ret)
0104         parent_br = region_np->parent;
0105
0106     /* If overlay has a list of bridges, use it. */
0107     br = of_parse_phandle(info->overlay, "fpga-bridges", 0);
0108     if (br) {
0109         of_node_put(br);
0110         np = info->overlay;
0111     } else {
0112         np = region_np;
0113     }
0114
0115     for (i = 0; ; i++) {
0116         br = of_parse_phandle(np, "fpga-bridges", i);
0117         if (!br)
0118             break;
0119
0120         /* If parent bridge is in list, skip it. */
0121         if (br == parent_br) {
0122             of_node_put(br);
0123             continue;
0124         }
0125
0126         /* If node is a bridge, get it and add to list */
0127         ret = of_fpga_bridge_get_to_list(br, info,
0128                          &region->bridge_list);
0129         of_node_put(br);
0130
0131         /* If any of the bridges are in use, give up */
0132         if (ret == -EBUSY) {
0133             fpga_bridges_put(&region->bridge_list);
0134             return -EBUSY;
0135         }
0136     }
0137
0138     return 0;
0139 }
0140
0141 /**
0142  * child_regions_with_firmware - Used to check the child region info.
0143  * @overlay: device node of the overlay
0144  *
0145  * If the overlay adds child FPGA regions, they are not allowed to have
0146  * firmware-name property.
0147  *
0148  * Return: 0 for OK or -EINVAL if child FPGA region adds firmware-name.
0149  */
0150 static int child_regions_with_firmware(struct device_node *overlay)
0151 {
0152     struct device_node *child_region;
0153     const char *child_firmware_name;
0154     int ret = 0;
0155
0156     of_node_get(overlay);
0157
0158     child_region = of_find_matching_node(overlay, fpga_region_of_match);
0159     while (child_region) {
0160         if (!of_property_read_string(child_region, "firmware-name",
0161                          &child_firmware_name)) {
0162             ret = -EINVAL;
0163             break;
0164         }
0165         child_region = of_find_matching_node(child_region,
0166                              fpga_region_of_match);
0167     }
0168
0169     of_node_put(child_region);
0170
0171     if (ret)
0172         pr_err("firmware-name not allowed in child FPGA region: %pOF",
0173                child_region);
0174
0175     return ret;
0176 }
0177
0178 /**
0179  * of_fpga_region_parse_ov - parse and check overlay applied to region
0180  *
0181  * @region: FPGA region
0182  * @overlay: overlay applied to the FPGA region
0183  *
0184  * Given an overlay applied to an FPGA region, parse the FPGA image specific
0185  * info in the overlay and do some checking.
0186  *
0187  * Return:
0188  *   NULL if overlay doesn't direct us to program the FPGA.
0189  *   fpga_image_info struct if there is an image to program.
0190  *   error code for invalid overlay.
0191  */
0192 static struct fpga_image_info *
0193 of_fpga_region_parse_ov(struct fpga_region *region,
0194             struct device_node *overlay)
0195 {
0196     struct device *dev = &region->dev;
0197     struct fpga_image_info *info;
0198     const char *firmware_name;
0199     int ret;
0200
0201     if (region->info) {
0202         dev_err(dev, "Region already has overlay applied.\n");
0203         return ERR_PTR(-EINVAL);
0204     }
0205
0206     /*
0207      * Reject overlay if child FPGA Regions added in the overlay have
0208      * firmware-name property (would mean that an FPGA region that has
0209      * not been added to the live tree yet is doing FPGA programming).
0210      */
0211     ret = child_regions_with_firmware(overlay);
0212     if (ret)
0213         return ERR_PTR(ret);
0214
0215     info = fpga_image_info_alloc(dev);
0216     if (!info)
0217         return ERR_PTR(-ENOMEM);
0218
0219     info->overlay = overlay;
0220
0221     /* Read FPGA region properties from the overlay */
0222     if (of_property_read_bool(overlay, "partial-fpga-config"))
0223         info->flags |= FPGA_MGR_PARTIAL_RECONFIG;
0224
0225     if (of_property_read_bool(overlay, "external-fpga-config"))
0226         info->flags |= FPGA_MGR_EXTERNAL_CONFIG;
0227
0228     if (of_property_read_bool(overlay, "encrypted-fpga-config"))
0229         info->flags |= FPGA_MGR_ENCRYPTED_BITSTREAM;
0230
0231     if (!of_property_read_string(overlay, "firmware-name",
0232                      &firmware_name)) {
0233         info->firmware_name = devm_kstrdup(dev, firmware_name,
0234                            GFP_KERNEL);
0235         if (!info->firmware_name)
0236             return ERR_PTR(-ENOMEM);
0237     }
0238
0239     of_property_read_u32(overlay, "region-unfreeze-timeout-us",
0240                  &info->enable_timeout_us);
0241
0242     of_property_read_u32(overlay, "region-freeze-timeout-us",
0243                  &info->disable_timeout_us);
0244
0245     of_property_read_u32(overlay, "config-complete-timeout-us",
0246                  &info->config_complete_timeout_us);
0247
0248     /* If overlay is not programming the FPGA, don't need FPGA image info */
0249     if (!info->firmware_name) {
0250         ret = 0;
0251         goto ret_no_info;
0252     }
0253
0254     /*
0255      * If overlay informs us FPGA was externally programmed, specifying
0256      * firmware here would be ambiguous.
0257      */
0258     if (info->flags & FPGA_MGR_EXTERNAL_CONFIG) {
0259         dev_err(dev, "error: specified firmware and external-fpga-config");
0260         ret = -EINVAL;
0261         goto ret_no_info;
0262     }
0263
0264     return info;
0265 ret_no_info:
0266     fpga_image_info_free(info);
0267     return ERR_PTR(ret);
0268 }
0269
0270 /**
0271  * of_fpga_region_notify_pre_apply - pre-apply overlay notification
0272  *
0273  * @region: FPGA region that the overlay was applied to
0274  * @nd: overlay notification data
0275  *
0276  * Called when an overlay targeted to an FPGA Region is about to be applied.
0277  * Parses the overlay for properties that influence how the FPGA will be
0278  * programmed and does some checking. If the checks pass, programs the FPGA.
0279  * If the checks fail, overlay is rejected and does not get added to the
0280  * live tree.
0281  *
0282  * Return: 0 for success or negative error code for failure.
0283  */
0284 static int of_fpga_region_notify_pre_apply(struct fpga_region *region,
0285                        struct of_overlay_notify_data *nd)
0286 {
0287     struct device *dev = &region->dev;
0288     struct fpga_image_info *info;
0289     int ret;
0290
0291     info = of_fpga_region_parse_ov(region, nd->overlay);
0292     if (IS_ERR(info))
0293         return PTR_ERR(info);
0294
0295     /* If overlay doesn't program the FPGA, accept it anyway. */
0296     if (!info)
0297         return 0;
0298
0299     if (region->info) {
0300         dev_err(dev, "Region already has overlay applied.\n");
0301         return -EINVAL;
0302     }
0303
0304     region->info = info;
0305     ret = fpga_region_program_fpga(region);
0306     if (ret) {
0307         /* error; reject overlay */
0308         fpga_image_info_free(info);
0309         region->info = NULL;
0310     }
0311
0312     return ret;
0313 }
0314
0315 /**
0316  * of_fpga_region_notify_post_remove - post-remove overlay notification
0317  *
0318  * @region: FPGA region that was targeted by the overlay that was removed
0319  * @nd: overlay notification data
0320  *
0321  * Called after an overlay has been removed if the overlay's target was a
0322  * FPGA region.
0323  */
0324 static void of_fpga_region_notify_post_remove(struct fpga_region *region,
0325                           struct of_overlay_notify_data *nd)
0326 {
0327     fpga_bridges_disable(&region->bridge_list);
0328     fpga_bridges_put(&region->bridge_list);
0329     fpga_image_info_free(region->info);
0330     region->info = NULL;
0331 }
0332
0333 /**
0334  * of_fpga_region_notify - reconfig notifier for dynamic DT changes
0335  * @nb:     notifier block
0336  * @action: notifier action
0337  * @arg:    reconfig data
0338  *
0339  * This notifier handles programming an FPGA when a "firmware-name" property is
0340  * added to an fpga-region.
0341  *
0342  * Return: NOTIFY_OK or error if FPGA programming fails.
0343  */
0344 static int of_fpga_region_notify(struct notifier_block *nb,
0345                  unsigned long action, void *arg)
0346 {
0347     struct of_overlay_notify_data *nd = arg;
0348     struct fpga_region *region;
0349     int ret;
0350
0351     switch (action) {
0352     case OF_OVERLAY_PRE_APPLY:
0353         pr_debug("%s OF_OVERLAY_PRE_APPLY\n", __func__);
0354         break;
0355     case OF_OVERLAY_POST_APPLY:
0356         pr_debug("%s OF_OVERLAY_POST_APPLY\n", __func__);
0357         return NOTIFY_OK;       /* not for us */
0358     case OF_OVERLAY_PRE_REMOVE:
0359         pr_debug("%s OF_OVERLAY_PRE_REMOVE\n", __func__);
0360         return NOTIFY_OK;       /* not for us */
0361     case OF_OVERLAY_POST_REMOVE:
0362         pr_debug("%s OF_OVERLAY_POST_REMOVE\n", __func__);
0363         break;
0364     default:            /* should not happen */
0365         return NOTIFY_OK;
0366     }
0367
0368     region = of_fpga_region_find(nd->target);
0369     if (!region)
0370         return NOTIFY_OK;
0371
0372     ret = 0;
0373     switch (action) {
0374     case OF_OVERLAY_PRE_APPLY:
0375         ret = of_fpga_region_notify_pre_apply(region, nd);
0376         break;
0377
0378     case OF_OVERLAY_POST_REMOVE:
0379         of_fpga_region_notify_post_remove(region, nd);
0380         break;
0381     }
0382
0383     put_device(&region->dev);
0384
0385     if (ret)
0386         return notifier_from_errno(ret);
0387
0388     return NOTIFY_OK;
0389 }
0390
0391 static struct notifier_block fpga_region_of_nb = {
0392     .notifier_call = of_fpga_region_notify,
0393 };
0394
0395 static int of_fpga_region_probe(struct platform_device *pdev)
0396 {
0397     struct device *dev = &pdev->dev;
0398     struct device_node *np = dev->of_node;
0399     struct fpga_region *region;
0400     struct fpga_manager *mgr;
0401     int ret;
0402
0403     /* Find the FPGA mgr specified by region or parent region. */
0404     mgr = of_fpga_region_get_mgr(np);
0405     if (IS_ERR(mgr))
0406         return -EPROBE_DEFER;
0407
0408     region = fpga_region_register(dev, mgr, of_fpga_region_get_bridges);
0409     if (IS_ERR(region)) {
0410         ret = PTR_ERR(region);
0411         goto eprobe_mgr_put;
0412     }
0413
0414     of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
0415     platform_set_drvdata(pdev, region);
0416
0417     dev_info(dev, "FPGA Region probed\n");
0418
0419     return 0;
0420
0421 eprobe_mgr_put:
0422     fpga_mgr_put(mgr);
0423     return ret;
0424 }
0425
0426 static int of_fpga_region_remove(struct platform_device *pdev)
0427 {
0428     struct fpga_region *region = platform_get_drvdata(pdev);
0429     struct fpga_manager *mgr = region->mgr;
0430
0431     fpga_region_unregister(region);
0432     fpga_mgr_put(mgr);
0433
0434     return 0;
0435 }
0436
0437 static struct platform_driver of_fpga_region_driver = {
0438     .probe = of_fpga_region_probe,
0439     .remove = of_fpga_region_remove,
0440     .driver = {
0441         .name   = "of-fpga-region",
0442         .of_match_table = of_match_ptr(fpga_region_of_match),
0443     },
0444 };
0445
0446 /**
0447  * of_fpga_region_init - init function for fpga_region class
0448  * Creates the fpga_region class and registers a reconfig notifier.
0449  *
0450  * Return: 0 on success, negative error code otherwise.
0451  */
0452 static int __init of_fpga_region_init(void)
0453 {
0454     int ret;
0455
0456     ret = of_overlay_notifier_register(&fpga_region_of_nb);
0457     if (ret)
0458         return ret;
0459
0460     ret = platform_driver_register(&of_fpga_region_driver);
0461     if (ret)
0462         goto err_plat;
0463
0464     return 0;
0465
0466 err_plat:
0467     of_overlay_notifier_unregister(&fpga_region_of_nb);
0468     return ret;
0469 }
0470
0471 static void __exit of_fpga_region_exit(void)
0472 {
0473     platform_driver_unregister(&of_fpga_region_driver);
0474     of_overlay_notifier_unregister(&fpga_region_of_nb);
0475 }
0476
0477 subsys_initcall(of_fpga_region_init);
0478 module_exit(of_fpga_region_exit);
0479
0480 MODULE_DESCRIPTION("FPGA Region");
0481 MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
0482 MODULE_LICENSE("GPL v2");