From 1f96e95fde079b6eec0d59030d7828f9ded78d45 Mon Sep 17 00:00:00 2001
From: Benjamin Valentin <benjamin.valentin@ml-pa.com>
Date: Wed, 30 Mar 2022 13:56:43 +0200
Subject: [PATCH] cpu/sam0_eth: implement SLEEP state

This saves ~3 mA when the device is in SLEEP mode.
---
 cpu/sam0_common/periph/eth.c          | 40 ++++++++++++++++++++++-----
 cpu/sam0_common/sam0_eth/eth-netdev.c | 21 ++++++++++++++
 2 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/cpu/sam0_common/periph/eth.c b/cpu/sam0_common/periph/eth.c
index 8bc848125e..3b06ce21aa 100644
--- a/cpu/sam0_common/periph/eth.c
+++ b/cpu/sam0_common/periph/eth.c
@@ -92,6 +92,8 @@ static uint8_t  rx_buf[ETH_RX_BUFFER_COUNT][ETH_RX_BUFFER_SIZE] __attribute__((a
 static uint8_t  tx_buf[ETH_TX_BUFFER_COUNT][ETH_TX_BUFFER_SIZE] __attribute__((aligned(GMAC_BUF_ALIGNMENT)));
 extern sam0_eth_netdev_t _sam0_eth_dev;
 
+static bool _is_sleeping;
+
 /* Flush our reception buffers and reset reception internal mechanism,
    this function may be call from ISR context */
 void sam0_clear_rx_buffers(void)
@@ -104,6 +106,33 @@ void sam0_clear_rx_buffers(void)
     GMAC->RBQB.reg = (uint32_t) rx_desc;
 }
 
+static void _enable_clock(void)
+{
+    /* Enable GMAC clocks */
+    MCLK->AHBMASK.reg |= MCLK_AHBMASK_GMAC;
+    MCLK->APBCMASK.reg |= MCLK_APBCMASK_GMAC;
+}
+
+static void _disable_clock(void)
+{
+    /* Disable GMAC clocks */
+    MCLK->AHBMASK.reg &= ~MCLK_AHBMASK_GMAC;
+    MCLK->APBCMASK.reg &= ~MCLK_APBCMASK_GMAC;
+}
+
+void sam0_eth_poweron(void)
+{
+    _enable_clock();
+    sam0_clear_rx_buffers();
+    _is_sleeping = false;
+}
+
+void sam0_eth_poweroff(void)
+{
+    _is_sleeping = true;
+    _disable_clock();
+}
+
 static void _init_desc_buf(void)
 {
     int i;
@@ -175,6 +204,10 @@ int sam0_eth_send(const struct iolist *iolist)
     unsigned tx_len = 0;
     tx_curr = &tx_desc[tx_idx];
 
+    if (_is_sleeping) {
+        return -ENOTSUP;
+    }
+
     /* load packet data into TX buffer */
     for (const iolist_t *iol = iolist; iol; iol = iol->iol_next) {
         if (tx_len + iol->iol_len > ETHERNET_MAX_LEN) {
@@ -290,13 +323,6 @@ int sam0_eth_receive_blocking(char *data, unsigned max_len)
     return _try_receive(data, max_len, 1);
 }
 
-static void _enable_clock(void)
-{
-    /* Enable GMAC clocks */
-    MCLK->AHBMASK.reg |= MCLK_AHBMASK_GMAC;
-    MCLK->APBCMASK.reg |= MCLK_APBCMASK_GMAC;
-}
-
 int sam0_eth_init(void)
 {
     /* Enable clocks */
diff --git a/cpu/sam0_common/sam0_eth/eth-netdev.c b/cpu/sam0_common/sam0_eth/eth-netdev.c
index e04616f9b0..48a1aa2fe8 100644
--- a/cpu/sam0_common/sam0_eth/eth-netdev.c
+++ b/cpu/sam0_common/sam0_eth/eth-netdev.c
@@ -36,6 +36,8 @@
 
 /* Internal helpers */
 extern int sam0_eth_init(void);
+extern void sam0_eth_poweron(void);
+extern void sam0_eth_poweroff(void);
 extern int sam0_eth_send(const struct iolist *iolist);
 extern int sam0_eth_receive_blocking(char *data, unsigned max_len);
 extern void sam0_eth_set_mac(const eui48_t *mac);
@@ -101,6 +103,22 @@ static int _sam0_eth_get(netdev_t *netdev, netopt_t opt, void *val, size_t max_l
     return res;
 }
 
+static int _set_state(netopt_state_t state)
+{
+    switch (state) {
+        case NETOPT_STATE_SLEEP:
+            sam0_eth_poweroff();
+            break;
+        case NETOPT_STATE_IDLE:
+            sam0_eth_poweron();
+            break;
+        default:
+            return -ENOTSUP;
+    }
+
+    return sizeof(netopt_state_t);
+}
+
 static int _sam0_eth_set(netdev_t *netdev, netopt_t opt, const void *val, size_t max_len)
 {
     int res = -1;
@@ -111,6 +129,9 @@ static int _sam0_eth_set(netdev_t *netdev, netopt_t opt, const void *val, size_t
             sam0_eth_set_mac((eui48_t *)val);
             res = ETHERNET_ADDR_LEN;
             break;
+        case NETOPT_STATE:
+            assert(max_len <= sizeof(netopt_state_t));
+            return _set_state(*((const netopt_state_t *)val));
         default:
             res = netdev_eth_set(netdev, opt, val, max_len);
             break;