nic: Fix incorrect wrap handling of RX circular buffer

nic: move other nic functions into the dedicated nic files
uip: alloc buffer multiple of 8 bytes

Signed-off-by: João Silva <jgc3silva@gmail.com>

rtl837x_nic.c

@@ -0,0 +1,90 @@
+#include "rtl837x_common.h"
+#include "rtl837x_regs.h"
+#include "rtl837x_sfr.h"
+#include "rtl837x_nic.h"
+
+extern __xdata uint8_t rx_headers[16];
+
+
+#ifndef RTLP_HOST_TEST
+/* One RX DMA operation, starting inside the configured ring. The hardware
+ * wraps transfers that cross its end; the initial address must be normalized.
+ * Host tests supply a simulated DMA engine for this hardware boundary. */
+bool nic_rx_dma(__xdata uint8_t *buffer, uint16_t ring_ptr, uint8_t words) __reentrant
+{
+	uint16_t guard = 0;
+
+	SFR_NIC_DATA_U16LE = (uint16_t)buffer;
+	SFR_NIC_RING_U16LE = ring_ptr;
+	SFR_NIC_CTRL = words;
+	while (SFR_NIC_CTRL != 0) {
+		if (++guard == 0) {
+			print_string("NIC: RX transfer did not complete\n");
+			return false;
+		}
+	}
+	return true;
+}
+#endif
+
+static bool nic_rx_copy(__xdata uint8_t *buffer, uint16_t ring_ptr, uint8_t words) __reentrant
+{
+	if (ring_ptr > RTL837X_NIC_RX_RING_BYTES || (ring_ptr & 7))
+		return false;
+	if (ring_ptr == RTL837X_NIC_RX_RING_BYTES)
+		ring_ptr = 0;
+
+	return nic_rx_dma(buffer, ring_ptr, words);
+}
+
+
+bool nic_rx_header(uint16_t ring_ptr) __reentrant
+{
+	if (ring_ptr >= RTL837X_NIC_RX_RING_BYTES)
+		return false;
+	return nic_rx_copy(rx_headers, ring_ptr, 1);
+}
+
+
+bool nic_rx_packet(__xdata uint8_t *buffer, uint16_t ring_ptr) __reentrant
+{
+	uint16_t len = ((uint16_t)rx_headers[5] << 8) | rx_headers[4];
+
+	if (!len || len > UIP_CONF_BUFFER_SIZE)
+		return false;
+	return nic_rx_copy(buffer, ring_ptr, (len + 7) >> 3);
+}
+
+
+/*
+ * Transfers data in XMEM to the ASIC for transmission by the NIC
+ */
+void nic_tx_packet(__xdata uint8_t *buffer, uint16_t len, uint16_t ring_ptr)
+{
+	uint16_t guard = 0;
+
+	SFR_NIC_DATA_U16LE = (uint16_t)(uintptr_t)buffer;
+
+#ifdef RXTXDBG
+	print_string("TX: \n");
+	for (uint8_t i = 0; i < 100; i++) {
+		print_byte(uip_buf[i]);
+		write_char(' ');
+	}
+	write_char('\n');
+#endif
+
+	ring_ptr <<= 3;
+	ring_ptr |= 0x8000;
+	SFR_NIC_RING_U16LE = ring_ptr;
+
+	len += 0xf;
+	len >>= 3;
+	SFR_NIC_CTRL = len;
+	while (SFR_NIC_CTRL != 0) {
+		if (++guard == 0) {
+			print_string("NIC: TX transfer did not complete\n");
+			return;
+		}
+	}
+}