diff --git a/arch/at91sam3x8e/serial.c b/arch/at91sam3x8e/serial.c index 629233d..84aaa96 100644 --- a/arch/at91sam3x8e/serial.c +++ b/arch/at91sam3x8e/serial.c @@ -2,6 +2,7 @@ /* See the end of this file for copyright, licensing, and warranty information. */ #include +#include #include #include #include @@ -83,7 +84,7 @@ void arch_serial_exit(struct serial_device *dev) ssize_t arch_serial_write(struct serial_device *dev, const void *buf, size_t len) { - struct arch_serial_buffer *arch_buf = NULL; + struct dmabuf *dmabuf = NULL; struct arch_serial_device *arch_dev = to_arch_serial_device(dev); if (arch_dev->tx_next != NULL) @@ -92,23 +93,22 @@ ssize_t arch_serial_write(struct serial_device *dev, const void *buf, size_t len if (len >= (1 << 16)) /* DMA uses 16-bit counters */ len = 0xffff; - arch_buf = malloc(sizeof(*arch_buf) + len); - if (arch_buf == NULL) + dmabuf = dmabuf_create(&dev->device, len); + if (dmabuf == NULL) return -ENOMEM; - memcpy(&arch_buf->data[0], buf, len); - arch_buf->len = (uint16_t)len; + memcpy(&dmabuf->data[0], buf, len); if (arch_dev->tx_current == NULL) { - arch_dev->tx_current = arch_buf; - REG_UART_PDC_TPR = (uint32_t)&arch_buf->data[0]; - REG_UART_PDC_TCR = arch_buf->len; + arch_dev->tx_current = dmabuf; + REG_UART_PDC_TPR = (uint32_t)&dmabuf->data[0]; + REG_UART_PDC_TCR = (uint16_t)dmabuf->len; /* we weren't transmitting, so the interrupt was masked */ REG_UART_IER = REG_UART_IER_ENDTX_MASK; } else { - arch_dev->tx_next = arch_buf; - REG_UART_PDC_TNPR = (uint32_t)&arch_buf->data[0]; - REG_UART_PDC_TNCR = arch_buf->len; + arch_dev->tx_next = dmabuf; + REG_UART_PDC_TNPR = (uint32_t)&dmabuf->data[0]; + REG_UART_PDC_TNCR = (uint16_t)dmabuf->len; } return (ssize_t)len; @@ -128,7 +128,7 @@ void irq_uart(void) /* REG_UART_PDC_TCR has reached zero */ if (state & REG_UART_SR_ENDTX_MASK) { /* this might be NULL but that's ok because free() tolerates that */ - free(arch_serial_default_device.tx_current); + dmabuf_put(arch_serial_default_device.tx_current); /* DMA automatically does this to the actual hardware registers */ arch_serial_default_device.tx_current = arch_serial_default_device.tx_next; diff --git a/include/arch/at91sam3x8e/serial.h b/include/arch/at91sam3x8e/serial.h index 9cd529f..59a2650 100644 --- a/include/arch/at91sam3x8e/serial.h +++ b/include/arch/at91sam3x8e/serial.h @@ -3,27 +3,20 @@ #pragma once +#include #include -#include #include -#include - #ifndef CONFIG_ARCH_SERIAL_BUFSZ #define CONFIG_ARCH_SERIAL_BUFSZ 32 #endif /* CONFIG_ARCH_SERIAL_BUFSZ */ -struct arch_serial_buffer { - uint16_t len; - uint8_t data[]; -}; - /** Architecture-specific extension of `struct serial_device` */ struct arch_serial_device { /** should always match REG_UART_PDC_TPR */ - struct arch_serial_buffer *tx_current; + struct dmabuf *tx_current; /** should always match REG_UART_PDC_TNPR */ - struct arch_serial_buffer *tx_next; + struct dmabuf *tx_next; struct serial_device device; }; diff --git a/include/ardix/dma.h b/include/ardix/dma.h new file mode 100644 index 0000000..14bd48b --- /dev/null +++ b/include/ardix/dma.h @@ -0,0 +1,54 @@ +/* SPDX-License-Identifier: BSD-3-Clause */ +/* See the end of this file for copyright, licensing, and warranty information. */ + +#pragma once + +#include +#include +#include + +struct dmabuf { + struct kent kent; + size_t len; + uint8_t data[0]; +}; + +/** + * Create a new DMA buffer and its corresponding kent. + * + * @param dev: device to create the buffer for + * @param len: buffer length in bytes + * @returns a pointer to the buffer, or `NULL` on failure + */ +struct dmabuf *dmabuf_create(struct device *dev, size_t len); + +/** Increment a DMA buffer's reference counter. */ +void dmabuf_get(struct dmabuf *buf); + +/** Decrement a DMA buffer's reference counter. */ +void dmabuf_put(struct dmabuf *buf); + +/* + * Copyright (c) 2021 Felix Kopp + * + * Redistribution and use in source and binary forms, with or without modification, are permitted + * provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, this list of + * conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright notice, this list of + * conditions and the following disclaimer in the documentation and/or other materials + * provided with the distribution. + * 3. Neither the name of the copyright holder nor the names of its contributors may be + * used to endorse or promote products derived from this software without specific prior + * written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND + * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, + * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY + * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ diff --git a/kernel/Makefile b/kernel/Makefile index a91ae3b..437115c 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -30,6 +30,7 @@ include $(ARDIX_KERNEL_PWD)/io/Makefile ARDIX_SOURCES += \ $(ARDIX_KERNEL_PWD)/device.c \ + $(ARDIX_KERNEL_PWD)/dma.c \ $(ARDIX_KERNEL_PWD)/kent.c \ $(ARDIX_KERNEL_PWD)/printk.c \ $(ARDIX_KERNEL_PWD)/ringbuf.c \ diff --git a/kernel/dma.c b/kernel/dma.c new file mode 100644 index 0000000..23be438 --- /dev/null +++ b/kernel/dma.c @@ -0,0 +1,76 @@ +/* SPDX-License-Identifier: BSD-3-Clause */ +/* See the end of this file for copyright, licensing, and warranty information. */ + +#include +#include +#include +#include +#include +#include + +#include + +static void dmabuf_destroy(struct kent *kent) +{ + struct dmabuf *buf = container_of(kent, struct dmabuf, kent); + free(buf); +} + +static struct kent_ops dma_kent_ops = { + .destroy = &dmabuf_destroy, +}; + +struct dmabuf *dmabuf_create(struct device *dev, size_t len) +{ + int err = 0; + struct dmabuf *buf = malloc(sizeof(*buf) + len); + if (buf == NULL) + return NULL; + + buf->kent.operations = &dma_kent_ops; + + err = kent_init(&dev->kent, &buf->kent); + if (err != 0) { + free(buf); + return NULL; + } + + buf->len = len; + + return buf; +} + +void dmabuf_get(struct dmabuf *buf) +{ + kent_get(&buf->kent); +} + +void dmabuf_put(struct dmabuf *buf) +{ + kent_put(&buf->kent); +} + +/* + * Copyright (c) 2021 Felix Kopp + * + * Redistribution and use in source and binary forms, with or without modification, are permitted + * provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, this list of + * conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright notice, this list of + * conditions and the following disclaimer in the documentation and/or other materials + * provided with the distribution. + * 3. Neither the name of the copyright holder nor the names of its contributors may be + * used to endorse or promote products derived from this software without specific prior + * written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND + * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, + * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY + * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */