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feat: exposes multiple maps #18

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feat: exposes multiple maps #18

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85ecee2
feat: exposes 3 maps with the same size
bellaz89 May 14, 2026
1c3ba39
feat: reduce memory consumption
bellaz89 May 15, 2026
681f7d4
feat: the number of maps is now a module parameter
bellaz89 May 15, 2026
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57 changes: 40 additions & 17 deletions uio-dummy.c
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@
* License, which you should have received with the source.
*
*/
/*
/*
* The UIO API
*
* In order to write a user-space driver using the UIO API with a
Expand Down Expand Up @@ -64,9 +64,9 @@
*
* You'll need to fill in entries for at least name, irq, irq_flags
* and handler, which should return IRQ_HANDLED.
*
*
* The structure should be register and unregistered with:
*
*
* int uio_register_device(struct device *parent, struct uio_info *info);
* void uio_unregister_device(struct uio_info *info);
*
Expand All @@ -86,10 +86,18 @@

static struct uio_info *info;
static struct device *dev;
static unsigned long long mem_size = 2692759552 + 32;
static int num_maps = 3;
static unsigned long long mem_sizes[MAX_UIO_MAPS] = {
81920,
2684477440,
81920,
81920,
81920,
};
static bool irqs_enabled = false;

module_param(mem_size, ullong, S_IRUGO);
module_param(num_maps, int, S_IRUGO);
module_param_array(mem_sizes, ullong, NULL, S_IRUGO);

static void my_release(struct device *dev)
{
Expand All @@ -98,8 +106,11 @@ static void my_release(struct device *dev)

static int uio_dummy_proc_show(struct seq_file *m, void *v)
{
int i;

seq_printf(m, "UIO Dummy driver v%s\n", UIO_DUMMY_VERSION);
seq_printf(m, " Allocated memory: %llu\n", mem_size);
for (i = 0; i < num_maps; i++)
seq_printf(m, " Allocated memory map%d: %llu\n", i, mem_sizes[i]);

return 0;
}
Expand Down Expand Up @@ -152,7 +163,14 @@ static int uio_dummy_irq_control(struct uio_info *dev_info, s32 irq_on)

static int __init uio_dummy_init(void)
{
struct uio_mem *mem;
int i;

if (num_maps < 1 || num_maps > MAX_UIO_MAPS) {
printk(KERN_ERR "uio_dummy: num_maps must be between 1 and %d\n",
MAX_UIO_MAPS);
return -EINVAL;
}

dev = kzalloc(sizeof(struct device), GFP_KERNEL);
dev_set_name(dev, "uio_dummy_device");
dev->release = my_release;
Expand All @@ -171,22 +189,25 @@ static int __init uio_dummy_init(void)
info->irq = UIO_IRQ_CUSTOM;
info->irqcontrol = uio_dummy_irq_control;

// Just allocate a slab of virtual memory to be exposed through mmap
mem = &info->mem[0];
mem->memtype = UIO_MEM_VIRTUAL;
mem->addr = (phys_addr_t)vmalloc(mem_size);
mem->size = mem_size;
mem->name = "UIO dummy memory block";
for (i = 0; i < num_maps; i++) {
info->mem[i].memtype = UIO_MEM_VIRTUAL;
info->mem[i].addr = (phys_addr_t)vzalloc(mem_sizes[i]);
info->mem[i].size = mem_sizes[i];
info->mem[i].name = "UIO dummy memory block";
}

if (uio_register_device(dev, info) < 0) {
vfree((const void *)mem->addr);
for (i = 0; i < num_maps; i++)
vfree((const void *)info->mem[i].addr);
device_unregister(dev);
kfree(dev);
kfree(info);
printk(KERN_INFO "Failing to register uio device\n");
return -1;
}
printk(KERN_INFO "Allocating %llu bytes for mem0", mem_size);

for (i = 0; i < num_maps; i++)
printk(KERN_INFO "Allocating %llu bytes for mem%d", mem_sizes[i], i);

proc_create_data("uio-dummy", 0666, NULL, &uio_dummy_proc_operations,
dev);
Expand All @@ -195,9 +216,11 @@ static int __init uio_dummy_init(void)

static void __exit uio_dummy_exit(void)
{
struct uio_mem *mem = &info->mem[0];
int i;

uio_unregister_device(info);
vfree((const void *)mem->addr);
for (i = 0; i < num_maps; i++)
vfree((const void *)info->mem[i].addr);
device_unregister(dev);
remove_proc_entry("uio-dummy", NULL);
printk(KERN_INFO "Un-Registered UIO handler\n");
Expand Down