This patch adds a mismatch between the Kconfig symbol (a bool) and the code (which suggests it could be built modular too).
On Mon, 2015-04-06 at 18:58 +0300, Andrew Andrianov wrote: > +config ION_PHYSMEM > + bool "Generic PhysMem ION driver" > + depends on ION > + help > + Provides a generic ION driver that registers the > + /dev/ion device with heaps from devicetree entries. > + This heaps are made of chunks of physical memory > --- a/drivers/staging/android/ion/Makefile > +++ b/drivers/staging/android/ion/Makefile > -obj-$(CONFIG_ION_DUMMY) += ion_dummy_driver.o > -obj-$(CONFIG_ION_TEGRA) += tegra/ > +obj-$(CONFIG_ION_DUMMY) += ion_dummy_driver.o > +obj-$(CONFIG_ION_PHYSMEM) += ion_physmem.o > +obj-$(CONFIG_ION_TEGRA) += tegra/ To make absolutely sure I'm reading this correctly: there's no way ion_physmem.o can ever be part of a module, right? (If I'm not reading this correctly you can stop reading here.) > --- /dev/null > +++ b/drivers/staging/android/ion/ion_physmem.c > @@ -0,0 +1,237 @@ > +/* > + * Copyright (C) 2015 RC Module > + * Andrew Andrianov <[email protected]> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * Generic devicetree physmem driver for ION Memory Manager > + * > + */ > +#include <linux/module.h> If this file can only be built-in this include might not be needed. > +MODULE_DEVICE_TABLE(of, of_match_table); MODULE_DEVICE_TABLE will always be preprocessed away for built-in code (see include/linux/module.h). > +static int ion_physmem_probe(struct platform_device *pdev) > +{ > + int ret; > + u32 ion_heap_id, ion_heap_align, ion_heap_type; > + ion_phys_addr_t addr; > + size_t size = 0; > + const char *ion_heap_name; > + struct resource *res; > + struct physmem_ion_dev *ipdev; > + > + /* > + Looks like we can only have one ION device in our system. > + Therefore we call ion_device_create on first probe and only > + add heaps to it on subsequent probe calls. > + FixMe: Do we need to hold a spinlock here once device probing > + becomes async? > + */ > + > + if (!idev) { > + idev = ion_device_create(ion_physmem_custom_ioctl); > + dev_info(&pdev->dev, "ion-physmem: ION PhysMem Driver. (c) RC > Module 2015\n"); > + if (!idev) > + return -ENOMEM; > + } > + > + ipdev = kzalloc(sizeof(struct physmem_ion_dev), GFP_KERNEL); > + if (!ipdev) > + return -ENOMEM; > + > + platform_set_drvdata(pdev, ipdev); > + > + ret = of_property_read_u32(pdev->dev.of_node, "ion-heap-id", > + &ion_heap_id); > + if (ret != 0) > + goto errfreeipdev; > + > + ret = of_property_read_u32(pdev->dev.of_node, "ion-heap-type", > + &ion_heap_type); > + if (ret != 0) > + goto errfreeipdev; > + > + ret = of_property_read_u32(pdev->dev.of_node, "ion-heap-align", > + &ion_heap_align); > + if (ret != 0) > + goto errfreeipdev; > + > + ret = of_property_read_string(pdev->dev.of_node, "ion-heap-name", > + &ion_heap_name); > + if (ret != 0) > + goto errfreeipdev; > + > + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "memory"); > + /* Not always needed, throw no error if missing */ > + if (res) { > + /* Fill in some defaults */ > + addr = res->start; > + size = resource_size(res); > + } > + > + switch (ion_heap_type) { > + case ION_HEAP_TYPE_DMA: > + if (res) { > + ret = dma_declare_coherent_memory(&pdev->dev, > + res->start, > + res->start, > + resource_size(res), > + DMA_MEMORY_MAP | > + DMA_MEMORY_EXCLUSIVE); > + if (ret == 0) { > + ret = -ENODEV; > + goto errfreeipdev; > + } > + } > + /* > + * If no memory region declared in dt we assume that > + * the user is okay with plain dma_alloc_coherent. > + */ > + break; > + case ION_HEAP_TYPE_CARVEOUT: > + case ION_HEAP_TYPE_CHUNK: > + { > + if (size == 0) { > + ret = -EIO; > + goto errfreeipdev; > + } > + ipdev->freepage_ptr = alloc_pages_exact(size, GFP_KERNEL); > + if (ipdev->freepage_ptr) { > + addr = virt_to_phys(ipdev->freepage_ptr); > + } else { > + ret = -ENOMEM; > + goto errfreeipdev; > + } > + break; > + } > + } > + > + ipdev->data.id = ion_heap_id; > + ipdev->data.type = ion_heap_type; > + ipdev->data.name = ion_heap_name; > + ipdev->data.align = ion_heap_align; > + ipdev->data.base = addr; > + ipdev->data.size = size; > + /* This one make dma_declare_coherent_memory actually work */ > + ipdev->data.priv = &pdev->dev; > + > + > + ipdev->heap = ion_heap_create(&ipdev->data); > + if (!ipdev->heap) > + goto errfreeipdev; > + > + if (!try_module_get(THIS_MODULE)) > + goto errfreeheap; For built-in only code THIS_MODULE will be, basically, always NULL. So, I think try_module_get() will always return true. > + ion_device_add_heap(idev, ipdev->heap); > + > + dev_info(&pdev->dev, "ion-physmem: heap %s id %d type %d align 0x%x at > phys 0x%lx len %lu KiB\n", > + ion_heap_name, ion_heap_id, ion_heap_type, ion_heap_align, > + (unsigned long int) addr, ((unsigned long int) size / 1024)); > + > + return 0; > + > +errfreeheap: > + kfree(ipdev->heap); > +errfreeipdev: > + kfree(ipdev); > + return -ENOMEM; > +} > + > +static int ion_physmem_remove(struct platform_device *pdev) > +{ > + struct physmem_ion_dev *ipdev = platform_get_drvdata(pdev); > + > + ion_heap_destroy(ipdev->heap); > + if (ipdev->need_free_coherent) > + dma_release_declared_memory(&pdev->dev); > + if (ipdev->freepage_ptr) > + free_pages_exact(ipdev->freepage_ptr, ipdev->data.size); > + kfree(ipdev->heap); > + kfree(ipdev); > + module_put(THIS_MODULE); Again, THIS_MODULE will be, basically, always NULL. > + return 0; > +} > + > +static struct platform_driver ion_physmem_driver = { > + .probe = ion_physmem_probe, > + .remove = ion_physmem_remove, > + .driver = { > + .owner = THIS_MODULE, Ditto. > + .name = "ion-physmem", > + .of_match_table = of_match_ptr(of_match_table), > + }, > +}; > +module_platform_driver(ion_physmem_driver); For built-in only code this is equivalent to, if I remember correctly, having a small wrapper call platform_driver_register(&ion_physmem_driver); and mark that wrapper with device_initcall(). > +MODULE_DESCRIPTION("Generic physmem driver for ION"); > +MODULE_AUTHOR("Andrew Andrianov <[email protected]>"); > +MODULE_LICENSE("GPL"); These macros will always be effectively preprocessed away for built-in only code. (If you plan to make ION_PHYSMEM tristate, you should note that "GPL" doesn't match the license stated in the comment at the top of this file, see include/linux/module.h.) Paul Bolle -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
