Sylvain Munaut | 26bc465 | 2020-09-14 10:19:49 +0200 | [diff] [blame] | 1 | /* |
| 2 | * dma.c |
| 3 | * |
| 4 | * Copyright (C) 2019-2020 Sylvain Munaut <tnt@246tNt.com> |
| 5 | * SPDX-License-Identifier: GPL-3.0-or-later |
| 6 | */ |
| 7 | |
| 8 | #include <stdbool.h> |
| 9 | #include <stdint.h> |
| 10 | |
| 11 | #include "config.h" |
| 12 | #include "dma.h" |
| 13 | |
| 14 | |
| 15 | struct dma { |
| 16 | uint32_t csr; |
| 17 | uint32_t _rsvd; |
| 18 | uint32_t addr_e1; |
| 19 | uint32_t addr_usb; |
| 20 | } __attribute__((packed,aligned(4))); |
| 21 | |
| 22 | #define DMA_CSR_GO (1 << 15) |
| 23 | #define DMA_CSR_BUSY (1 << 15) |
| 24 | #define DMA_DIR_E1_TO_USB (0 << 14) |
| 25 | #define DMA_DIR_USB_TO_E1 (1 << 14) |
| 26 | #define DMA_CSR_LEN(x) (((x)-2) & 0x1fff) |
| 27 | |
| 28 | static volatile struct dma * const dma_regs = (void*)(DMA_BASE); |
| 29 | |
| 30 | static struct { |
| 31 | bool pending; |
| 32 | dma_cb cb_fn; |
| 33 | void *cb_data; |
| 34 | } g_dma; |
| 35 | |
| 36 | |
| 37 | bool |
| 38 | dma_ready(void) |
| 39 | { |
| 40 | return !(dma_regs->csr & DMA_CSR_BUSY); |
| 41 | } |
| 42 | |
| 43 | void |
| 44 | dma_exec(unsigned addr_e1, unsigned addr_usb, unsigned len, bool dir, |
| 45 | dma_cb cb_fn, void *cb_data) |
| 46 | { |
| 47 | dma_regs->addr_e1 = addr_e1; |
| 48 | dma_regs->addr_usb = addr_usb; |
| 49 | dma_regs->csr = |
| 50 | DMA_CSR_GO | |
| 51 | (dir ? DMA_DIR_USB_TO_E1 : DMA_DIR_E1_TO_USB) | |
| 52 | DMA_CSR_LEN(len); |
| 53 | |
| 54 | g_dma.pending = true; |
| 55 | g_dma.cb_fn = cb_fn; |
| 56 | g_dma.cb_data = cb_data; |
| 57 | } |
| 58 | |
| 59 | bool |
| 60 | dma_poll(void) |
| 61 | { |
| 62 | if (g_dma.pending && dma_ready()) { |
| 63 | g_dma.pending = false; |
| 64 | if (g_dma.cb_fn) |
| 65 | g_dma.cb_fn(g_dma.cb_data); |
| 66 | } |
| 67 | |
| 68 | return g_dma.pending; |
| 69 | } |