Date: Sun, 17 Dec 2017 15:00:22 -0500 From: Lee D <embaudarm@gmail.com> To: freebsd-hackers@freebsd.org Subject: How do I alloc multiple memory regions specified in a device tree? Message-ID: <CANC_bnMjPzSKM0q1__or=cTrvoxnM_LXo-avFYgbUZVeZPT9wg@mail.gmail.com>
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Hi everyone.
I have a device driver that must access registers in multiple memory
ranges. How do I pull those values out of the device tree?
This is for a custom ARM embedded board.
bus_alloc_resource_any() works, but only for the first memory range.
The second time I call it, it crashes the kernel.
If I alloc the same memory resources by hardcoding the values in calls
to bus_alloc_resource(), it works.
The technique of calling bus_alloc_resource_any() multiple times is
used in src/sys/dev/sdhci/sdhci_fdt.c, but I can't get it to work.
Here is a snippet from my device tree:
...
fabric@40000000 {
device_type = "soc";
compatible = "simple-bus";
#address-cells = <0x1>;
#size-cells = <0x1>;
ranges = <0x0 0x40000000 0x5000000>;
my_lcd@3C00000 {
status = "okay";
compatible = "xlnx,my_lcd";
reg = <0x3C00000 0x1000
0x400000 0x1000
0x3000000 0x1000>;
interrupts = <0x0 0x1d 0x1>;
interrupt-parent = <0x1>;
};
...
Here is my driver code from my_lcd_attach:
rid=0;
sc->lcd_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
RF_ACTIVE);
if (sc->lcd_mem_res == NULL) {
my_lcd_detach(dev);
return (ENOMEM);
}
rid=0;
sc->dma_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
RF_ACTIVE);
if (sc->dma_mem_res == NULL) {
my_lcd_detach(dev);
return (ENOMEM);
}
Thank you.
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