zynq-rs/libboard_zynq/src/sdio/adma.rs

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/// ADMA library
use core::mem::MaybeUninit;
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use super::SDIO;
use libcortex_a9::cache;
use libregister::{
register, register_bit,
RegisterR, RegisterW, RegisterRW, VolatileCell,
};
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#[repr(C, align(4))]
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pub struct Adma2Desc32 {
attribute: Desc32Attribute,
length: VolatileCell<u16>,
address: VolatileCell<u32>,
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}
// Default::default() cannot be used as it is not a constant function...
static mut ADMA2_DESCR32_TABLE: MaybeUninit<[Adma2Desc32; 32]> = MaybeUninit::uninit();
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#[allow(unused)]
const DESC_MAX_LENGTH: u32 = 65536;
register!(desc32_attribute, Desc32Attribute, VolatileCell, u16);
register_bit!(desc32_attribute, trans, 5);
register_bit!(desc32_attribute, int, 2);
register_bit!(desc32_attribute, end, 1);
register_bit!(desc32_attribute, valid, 0);
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/// Initialize `ADMA2_DESCR32_TABLE` and setup `adma_system_address`
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pub fn setup_adma2_descr32(sdio: &mut SDIO, blk_cnt: u32, buffer: &[u8]) {
let descr_table = unsafe { &mut *ADMA2_DESCR32_TABLE.as_mut_ptr() };
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let blk_size = sdio
.regs
.block_size_block_count
.read()
.transfer_block_size() as u32;
let total_desc_lines = if blk_size * blk_cnt < DESC_MAX_LENGTH {
1
} else {
blk_size * blk_cnt / DESC_MAX_LENGTH
+ if (blk_size * blk_cnt) % DESC_MAX_LENGTH == 0 {
0
} else {
1
}
} as usize;
let ptr = buffer.as_ptr() as u32;
for desc_num in 0..total_desc_lines {
descr_table[desc_num].address.set(ptr + (desc_num as u32) * DESC_MAX_LENGTH);
descr_table[desc_num].attribute.write(
Desc32Attribute::zeroed()
.trans(true)
.valid(true)
);
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// 0 is the max length (65536)
descr_table[desc_num].length.set(0);
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}
descr_table[total_desc_lines - 1].attribute.modify(|_, w| w.end(true));
descr_table[total_desc_lines - 1].length.set(
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(blk_cnt * blk_size - ((total_desc_lines as u32) - 1) * DESC_MAX_LENGTH) as u16,
);
unsafe {
sdio.regs
.adma_system_address
.write(descr_table.as_ptr() as u32);
}
cache::dcci_slice(descr_table);
}