[net-next.git 0/6 (V5)] stmmac: remove dead code for STMMAC_TIMER and add new mitigation schema

[net-next.git 0/6 (V5)] stmmac: remove dead code for STMMAC_TIMER and add new mitigation schema

[Giuseppe CAVALLARO]

These patch series remove the STMMAC_TIMER option no longer updated
and never used and add a new mitigation schema.
Having removed the Timer opt, this has made the driver slim.
On top of this work, it has been easier to introduce the new
mitigation schema based on HW RX-watchdog (available in new cores).
In fact, 3.50 and newer cores have an HW RX-Watchdog that can be used for 
mitigating the Rx-interrupts and first results look promising.

Running n-u-t-t-c-p with the following parameters:

 Throughput: 500Mbps
 UDP Buffer size: 1328bytes
 TCP Buffer size: 65536bytes

for example, I got on ST box (arm-based) these improvements:

--------------------------------------------------------------------
      Original                   |     With New Mitigation patch
--------------------------------------------------------------------
 Test        CPU usage  pkt/loss |        CPU usage     pkt/loss
 Type  Mbps        %         %   |Mbps      %              %
--------------------------------------------------------------------
UDP-RX 395.5065 95       20.89   |499.8811  23        0.00
UDP-TX 499.5578 100     0.08915  |499.1340  99        0.00
TCP-RX 499.9221 77               |499.8776  26
TCP-TX 389.5719 99               |499.9771  79
--------------------------------------------------------------------

 ... no regression on ST boxes (SH based) I always test.

This is a brief explanation of the new mitigation schema although there
is a patch that updates the driver's documentation.

o On Rx-side I have:
  New GMACs will use the RX-watchdog timer; old ones will continue to
  use NAPI to mitigate the RX DMA interrupts.
  For the RX-watchdog, there is a parameter that is the RI Watchdog 
  Timer count. It indicates the number of system clock cycles and can be
  set via *ethtool*.

o On Tx-side, the mitigation schema is based on a SW timer
  that calls the tx function (stmmac_tx) to reclaim the resource after
  transmitting the frames.
  Also there is another parameter (a threshold) used to program
  the descriptors avoiding to set the interrupt on completion bit in
  when the frame is sent (xmit). 

V2: these patches add the ethtool support to get/set coalesce parameters
and totally remove the sysFS support added in the first patches.

V3: added several fixes: for example NAPI and RX-watchdog work together
while in the previous implementation the HW  RX-watchdog disabled NAPI.
On the tx side, erroneously the tx coalesce frame parameter was limited
to the ring size and the driver didn't take care of the segment numbers
when enable/disable the IC bit in the TDES.

V4: reject not supported coalesce settings in ethtool.

V5: in these new patch series, I am releasing two patches that
add the mitigation for tx and rx where I collected the feedback received
from the mailing list.  Concerning the tx, I've also reworked and
fixed the spinlock irqsave and restore as D. Miller had suggested (thx).

Giuseppe Cavallaro (6):
  stmmac: remove dead code for STMMAC_TIMER support
  stmmac: add the initial tx coalesce schema
  stmmac: add Rx watchdog support to mitigate the DMA irqs
  stmmac: get/set coalesce parameters via ethtool
  stmmac: update the doc with new IRQ mitigation
  stmmac: update the driver version to Nov_2012

 Documentation/networking/stmmac.txt                |   28 ++-
 drivers/net/ethernet/stmicro/stmmac/Kconfig        |   25 --
 drivers/net/ethernet/stmicro/stmmac/Makefile       |    1 -
 drivers/net/ethernet/stmicro/stmmac/common.h       |   39 +++-
 drivers/net/ethernet/stmicro/stmmac/dwmac1000.h    |    3 -
 .../net/ethernet/stmicro/stmmac/dwmac1000_dma.c    |    6 +
 drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h    |    5 +-
 drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c    |   20 ++-
 drivers/net/ethernet/stmicro/stmmac/stmmac.h       |   14 +-
 .../net/ethernet/stmicro/stmmac/stmmac_ethtool.c   |  100 +++++++-
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c  |  261 ++++++++------------
 drivers/net/ethernet/stmicro/stmmac/stmmac_timer.c |  134 ----------
 drivers/net/ethernet/stmicro/stmmac/stmmac_timer.h |   46 ----
 include/linux/stmmac.h                             |    1 +
 14 files changed, 281 insertions(+), 402 deletions(-)
 delete mode 100644 drivers/net/ethernet/stmicro/stmmac/stmmac_timer.c
 delete mode 100644 drivers/net/ethernet/stmicro/stmmac/stmmac_timer.h

-- 
1.7.4.4

[net-next.git 1/6] stmmac: remove dead code for STMMAC_TIMER support

[Giuseppe CAVALLARO]

The TIMER option is not longer supported and this
code can be considered dead for this driver in
the new kernel series.
In fact, It was not updated at all and never used.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
---
 drivers/net/ethernet/stmicro/stmmac/Kconfig        |   25 ----
 drivers/net/ethernet/stmicro/stmmac/Makefile       |    1 -
 drivers/net/ethernet/stmicro/stmmac/stmmac.h       |    6 -
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c  |  101 +--------------
 drivers/net/ethernet/stmicro/stmmac/stmmac_timer.c |  134 --------------------
 drivers/net/ethernet/stmicro/stmmac/stmmac_timer.h |   46 -------
 6 files changed, 3 insertions(+), 310 deletions(-)
 delete mode 100644 drivers/net/ethernet/stmicro/stmmac/stmmac_timer.c
 delete mode 100644 drivers/net/ethernet/stmicro/stmmac/stmmac_timer.h

diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
index 9f44827..1164930 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
+++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
@@ -54,31 +54,6 @@ config STMMAC_DA
 	  By default, the DMA arbitration scheme is based on Round-robin
 	  (rx:tx priority is 1:1).
 
-config STMMAC_TIMER
-	bool "STMMAC Timer optimisation"
-	default n
-	depends on RTC_HCTOSYS_DEVICE
-	---help---
-	  Use an external timer for mitigating the number of network
-	  interrupts. Currently, for SH architectures, it is possible
-	  to use the TMU channel 2 and the SH-RTC device.
-
-choice
-        prompt "Select Timer device"
-        depends on STMMAC_TIMER
-
-config STMMAC_TMU_TIMER
-        bool "TMU channel 2"
-        depends on CPU_SH4
-	---help---
-
-config STMMAC_RTC_TIMER
-        bool "Real time clock"
-        depends on RTC_CLASS
-	---help---
-
-endchoice
-
 choice
 	prompt "Select the DMA TX/RX descriptor operating modes"
 	depends on STMMAC_ETH
diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
index bc965ac..c8e8ea6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Makefile
+++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
@@ -1,5 +1,4 @@
 obj-$(CONFIG_STMMAC_ETH) += stmmac.o
-stmmac-$(CONFIG_STMMAC_TIMER) += stmmac_timer.o
 stmmac-$(CONFIG_STMMAC_RING) += ring_mode.o
 stmmac-$(CONFIG_STMMAC_CHAINED) += chain_mode.o
 stmmac-$(CONFIG_STMMAC_PLATFORM) += stmmac_platform.o
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index 7d51a65..5f89415 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -31,9 +31,6 @@
 #include <linux/phy.h>
 #include <linux/pci.h>
 #include "common.h"
-#ifdef CONFIG_STMMAC_TIMER
-#include "stmmac_timer.h"
-#endif
 
 struct stmmac_priv {
 	/* Frequently used values are kept adjacent for cache effect */
@@ -77,9 +74,6 @@ struct stmmac_priv {
 	spinlock_t tx_lock;
 	int wolopts;
 	int wol_irq;
-#ifdef CONFIG_STMMAC_TIMER
-	struct stmmac_timer *tm;
-#endif
 	struct plat_stmmacenet_data *plat;
 	struct stmmac_counters mmc;
 	struct dma_features dma_cap;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index c6cdbc4..777234c 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -115,16 +115,6 @@ static int tc = TC_DEFAULT;
 module_param(tc, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(tc, "DMA threshold control value");
 
-/* Pay attention to tune this parameter; take care of both
- * hardware capability and network stabitily/performance impact.
- * Many tests showed that ~4ms latency seems to be good enough. */
-#ifdef CONFIG_STMMAC_TIMER
-#define DEFAULT_PERIODIC_RATE	256
-static int tmrate = DEFAULT_PERIODIC_RATE;
-module_param(tmrate, int, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(tmrate, "External timer freq. (default: 256Hz)");
-#endif
-
 #define DMA_BUFFER_SIZE	BUF_SIZE_2KiB
 static int buf_sz = DMA_BUFFER_SIZE;
 module_param(buf_sz, int, S_IRUGO | S_IWUSR);
@@ -536,12 +526,6 @@ static void init_dma_desc_rings(struct net_device *dev)
 	else
 		bfsize = stmmac_set_bfsize(dev->mtu, priv->dma_buf_sz);
 
-#ifdef CONFIG_STMMAC_TIMER
-	/* Disable interrupts on completion for the reception if timer is on */
-	if (likely(priv->tm->enable))
-		dis_ic = 1;
-#endif
-
 	DBG(probe, INFO, "stmmac: txsize %d, rxsize %d, bfsize %d\n",
 	    txsize, rxsize, bfsize);
 
@@ -775,22 +759,12 @@ static void stmmac_tx(struct stmmac_priv *priv)
 
 static inline void stmmac_enable_irq(struct stmmac_priv *priv)
 {
-#ifdef CONFIG_STMMAC_TIMER
-	if (likely(priv->tm->enable))
-		priv->tm->timer_start(tmrate);
-	else
-#endif
-		priv->hw->dma->enable_dma_irq(priv->ioaddr);
+	priv->hw->dma->enable_dma_irq(priv->ioaddr);
 }
 
 static inline void stmmac_disable_irq(struct stmmac_priv *priv)
 {
-#ifdef CONFIG_STMMAC_TIMER
-	if (likely(priv->tm->enable))
-		priv->tm->timer_stop();
-	else
-#endif
-		priv->hw->dma->disable_dma_irq(priv->ioaddr);
+	priv->hw->dma->disable_dma_irq(priv->ioaddr);
 }
 
 static int stmmac_has_work(struct stmmac_priv *priv)
@@ -818,25 +792,6 @@ static inline void _stmmac_schedule(struct stmmac_priv *priv)
 	}
 }
 
-#ifdef CONFIG_STMMAC_TIMER
-void stmmac_schedule(struct net_device *dev)
-{
-	struct stmmac_priv *priv = netdev_priv(dev);
-
-	priv->xstats.sched_timer_n++;
-
-	_stmmac_schedule(priv);
-}
-
-static void stmmac_no_timer_started(unsigned int x)
-{;
-};
-
-static void stmmac_no_timer_stopped(void)
-{;
-};
-#endif
-
 /**
  * stmmac_tx_err:
  * @priv: pointer to the private device structure
@@ -1038,23 +993,6 @@ static int stmmac_open(struct net_device *dev)
 	struct stmmac_priv *priv = netdev_priv(dev);
 	int ret;
 
-#ifdef CONFIG_STMMAC_TIMER
-	priv->tm = kzalloc(sizeof(struct stmmac_timer *), GFP_KERNEL);
-	if (unlikely(priv->tm == NULL))
-		return -ENOMEM;
-
-	priv->tm->freq = tmrate;
-
-	/* Test if the external timer can be actually used.
-	 * In case of failure continue without timer. */
-	if (unlikely((stmmac_open_ext_timer(dev, priv->tm)) < 0)) {
-		pr_warning("stmmaceth: cannot attach the external timer.\n");
-		priv->tm->freq = 0;
-		priv->tm->timer_start = stmmac_no_timer_started;
-		priv->tm->timer_stop = stmmac_no_timer_stopped;
-	} else
-		priv->tm->enable = 1;
-#endif
 	clk_prepare_enable(priv->stmmac_clk);
 
 	stmmac_check_ether_addr(priv);
@@ -1141,10 +1079,6 @@ static int stmmac_open(struct net_device *dev)
 	priv->hw->dma->start_tx(priv->ioaddr);
 	priv->hw->dma->start_rx(priv->ioaddr);
 
-#ifdef CONFIG_STMMAC_TIMER
-	priv->tm->timer_start(tmrate);
-#endif
-
 	/* Dump DMA/MAC registers */
 	if (netif_msg_hw(priv)) {
 		priv->hw->mac->dump_regs(priv->ioaddr);
@@ -1170,9 +1104,6 @@ open_error_wolirq:
 	free_irq(dev->irq, dev);
 
 open_error:
-#ifdef CONFIG_STMMAC_TIMER
-	kfree(priv->tm);
-#endif
 	if (priv->phydev)
 		phy_disconnect(priv->phydev);
 
@@ -1203,12 +1134,6 @@ static int stmmac_release(struct net_device *dev)
 
 	netif_stop_queue(dev);
 
-#ifdef CONFIG_STMMAC_TIMER
-	/* Stop and release the timer */
-	stmmac_close_ext_timer();
-	if (priv->tm != NULL)
-		kfree(priv->tm);
-#endif
 	napi_disable(&priv->napi);
 
 	/* Free the IRQ lines */
@@ -1323,12 +1248,6 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 	/* Interrupt on completition only for the latest segment */
 	priv->hw->desc->close_tx_desc(desc);
 
-#ifdef CONFIG_STMMAC_TIMER
-	/* Clean IC while using timer */
-	if (likely(priv->tm->enable))
-		priv->hw->desc->clear_tx_ic(desc);
-#endif
-
 	wmb();
 
 	/* To avoid raise condition */
@@ -1523,7 +1442,7 @@ static int stmmac_poll(struct napi_struct *napi, int budget)
  *  stmmac_tx_timeout
  *  @dev : Pointer to net device structure
  *  Description: this function is called when a packet transmission fails to
- *   complete within a reasonable tmrate. The driver will mark the error in the
+ *   complete within a reasonable time. The driver will mark the error in the
  *   netdev structure and arrange for the device to be reset to a sane state
  *   in order to transmit a new packet.
  */
@@ -2141,11 +2060,6 @@ int stmmac_suspend(struct net_device *ndev)
 	netif_device_detach(ndev);
 	netif_stop_queue(ndev);
 
-#ifdef CONFIG_STMMAC_TIMER
-	priv->tm->timer_stop();
-	if (likely(priv->tm->enable))
-		dis_ic = 1;
-#endif
 	napi_disable(&priv->napi);
 
 	/* Stop TX/RX DMA */
@@ -2196,10 +2110,6 @@ int stmmac_resume(struct net_device *ndev)
 	priv->hw->dma->start_tx(priv->ioaddr);
 	priv->hw->dma->start_rx(priv->ioaddr);
 
-#ifdef CONFIG_STMMAC_TIMER
-	if (likely(priv->tm->enable))
-		priv->tm->timer_start(tmrate);
-#endif
 	napi_enable(&priv->napi);
 
 	netif_start_queue(ndev);
@@ -2295,11 +2205,6 @@ static int __init stmmac_cmdline_opt(char *str)
 		} else if (!strncmp(opt, "eee_timer:", 6)) {
 			if (kstrtoint(opt + 10, 0, &eee_timer))
 				goto err;
-#ifdef CONFIG_STMMAC_TIMER
-		} else if (!strncmp(opt, "tmrate:", 7)) {
-			if (kstrtoint(opt + 7, 0, &tmrate))
-				goto err;
-#endif
 		}
 	}
 	return 0;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_timer.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_timer.c
deleted file mode 100644
index 4ccd4e2..0000000
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_timer.c
+++ /dev/null
@@ -1,134 +0,0 @@
-/*******************************************************************************
-  STMMAC external timer support.
-
-  Copyright (C) 2007-2009  STMicroelectronics Ltd
-
-  This program is free software; you can redistribute it and/or modify it
-  under the terms and conditions of the GNU General Public License,
-  version 2, as published by the Free Software Foundation.
-
-  This program is distributed in the hope it will be useful, but WITHOUT
-  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
-  more details.
-
-  You should have received a copy of the GNU General Public License along with
-  this program; if not, write to the Free Software Foundation, Inc.,
-  51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
-
-  The full GNU General Public License is included in this distribution in
-  the file called "COPYING".
-
-  Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
-*******************************************************************************/
-
-#include <linux/kernel.h>
-#include <linux/etherdevice.h>
-#include "stmmac_timer.h"
-
-static void stmmac_timer_handler(void *data)
-{
-	struct net_device *dev = (struct net_device *)data;
-
-	stmmac_schedule(dev);
-}
-
-#define STMMAC_TIMER_MSG(timer, freq) \
-printk(KERN_INFO "stmmac_timer: %s Timer ON (freq %dHz)\n", timer, freq);
-
-#if defined(CONFIG_STMMAC_RTC_TIMER)
-#include <linux/rtc.h>
-static struct rtc_device *stmmac_rtc;
-static rtc_task_t stmmac_task;
-
-static void stmmac_rtc_start(unsigned int new_freq)
-{
-	rtc_irq_set_freq(stmmac_rtc, &stmmac_task, new_freq);
-	rtc_irq_set_state(stmmac_rtc, &stmmac_task, 1);
-}
-
-static void stmmac_rtc_stop(void)
-{
-	rtc_irq_set_state(stmmac_rtc, &stmmac_task, 0);
-}
-
-int stmmac_open_ext_timer(struct net_device *dev, struct stmmac_timer *tm)
-{
-	stmmac_task.private_data = dev;
-	stmmac_task.func = stmmac_timer_handler;
-
-	stmmac_rtc = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE);
-	if (stmmac_rtc == NULL) {
-		pr_err("open rtc device failed\n");
-		return -ENODEV;
-	}
-
-	rtc_irq_register(stmmac_rtc, &stmmac_task);
-
-	/* Periodic mode is not supported */
-	if ((rtc_irq_set_freq(stmmac_rtc, &stmmac_task, tm->freq) < 0)) {
-		pr_err("set periodic failed\n");
-		rtc_irq_unregister(stmmac_rtc, &stmmac_task);
-		rtc_class_close(stmmac_rtc);
-		return -1;
-	}
-
-	STMMAC_TIMER_MSG(CONFIG_RTC_HCTOSYS_DEVICE, tm->freq);
-
-	tm->timer_start = stmmac_rtc_start;
-	tm->timer_stop = stmmac_rtc_stop;
-
-	return 0;
-}
-
-int stmmac_close_ext_timer(void)
-{
-	rtc_irq_set_state(stmmac_rtc, &stmmac_task, 0);
-	rtc_irq_unregister(stmmac_rtc, &stmmac_task);
-	rtc_class_close(stmmac_rtc);
-	return 0;
-}
-
-#elif defined(CONFIG_STMMAC_TMU_TIMER)
-#include <linux/clk.h>
-#define TMU_CHANNEL "tmu2_clk"
-static struct clk *timer_clock;
-
-static void stmmac_tmu_start(unsigned int new_freq)
-{
-	clk_set_rate(timer_clock, new_freq);
-	clk_prepare_enable(timer_clock);
-}
-
-static void stmmac_tmu_stop(void)
-{
-	clk_disable_unprepare(timer_clock);
-}
-
-int stmmac_open_ext_timer(struct net_device *dev, struct stmmac_timer *tm)
-{
-	timer_clock = clk_get(NULL, TMU_CHANNEL);
-
-	if (IS_ERR(timer_clock))
-		return -1;
-
-	if (tmu2_register_user(stmmac_timer_handler, (void *)dev) < 0) {
-		timer_clock = NULL;
-		return -1;
-	}
-
-	STMMAC_TIMER_MSG("TMU2", tm->freq);
-	tm->timer_start = stmmac_tmu_start;
-	tm->timer_stop = stmmac_tmu_stop;
-
-	return 0;
-}
-
-int stmmac_close_ext_timer(void)
-{
-	clk_disable_unprepare(timer_clock);
-	tmu2_unregister_user();
-	clk_put(timer_clock);
-	return 0;
-}
-#endif
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_timer.h b/drivers/net/ethernet/stmicro/stmmac/stmmac_timer.h
deleted file mode 100644
index aea9b14..0000000
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_timer.h
+++ /dev/null
@@ -1,46 +0,0 @@
-/*******************************************************************************
-  STMMAC external timer Header File.
-
-  Copyright (C) 2007-2009  STMicroelectronics Ltd
-
-  This program is free software; you can redistribute it and/or modify it
-  under the terms and conditions of the GNU General Public License,
-  version 2, as published by the Free Software Foundation.
-
-  This program is distributed in the hope it will be useful, but WITHOUT
-  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
-  more details.
-
-  You should have received a copy of the GNU General Public License along with
-  this program; if not, write to the Free Software Foundation, Inc.,
-  51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
-
-  The full GNU General Public License is included in this distribution in
-  the file called "COPYING".
-
-  Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
-*******************************************************************************/
-#ifndef __STMMAC_TIMER_H__
-#define __STMMAC_TIMER_H__
-
-struct stmmac_timer {
-	void (*timer_start) (unsigned int new_freq);
-	void (*timer_stop) (void);
-	unsigned int freq;
-	unsigned int enable;
-};
-
-/* Open the HW timer device and return 0 in case of success */
-int stmmac_open_ext_timer(struct net_device *dev, struct stmmac_timer *tm);
-/* Stop the timer and release it */
-int stmmac_close_ext_timer(void);
-/* Function used for scheduling task within the stmmac */
-void stmmac_schedule(struct net_device *dev);
-
-#if defined(CONFIG_STMMAC_TMU_TIMER)
-extern int tmu2_register_user(void *fnt, void *data);
-extern void tmu2_unregister_user(void);
-#endif
-
-#endif /* __STMMAC_TIMER_H__ */
-- 
1.7.4.4

[net-next.git 2/6 (V3)] stmmac: add the initial tx coalesce schema

[Giuseppe CAVALLARO]

This patch adds a new schema used for mitigating the
number of transmit interrupts.
It is based on a SW timer and a threshold value.
The timer is used to periodically call the stmmac_tx_clean
function; the threshold is used for setting the IC (Interrupt
on Completion bit). The ISR will then invoke the poll method.
Also the patch improves some ethtool stat fields.

V2: review the logic to manage the IC bit in the TDESC
that was bugged because it didn't take care about the
fragments. Also fix the tx_count_frames that has not to be
limited to TX DMA ring. Thanks to Ben Hutchings.

V3: removed the spin_lock irqsave/restore as D. Miller suggested.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
---
 drivers/net/ethernet/stmicro/stmmac/common.h       |   22 +++-
 drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c    |    7 +-
 drivers/net/ethernet/stmicro/stmmac/stmmac.h       |    4 +
 .../net/ethernet/stmicro/stmmac/stmmac_ethtool.c   |    8 +-
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c  |  132 ++++++++++++--------
 5 files changed, 111 insertions(+), 62 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
index 719be39..d17eeef 100644
--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -95,9 +95,12 @@ struct stmmac_extra_stats {
 	unsigned long threshold;
 	unsigned long tx_pkt_n;
 	unsigned long rx_pkt_n;
-	unsigned long poll_n;
-	unsigned long sched_timer_n;
 	unsigned long normal_irq_n;
+	unsigned long rx_normal_irq_n;
+	unsigned long napi_poll;
+	unsigned long tx_normal_irq_n;
+	unsigned long tx_clean;
+	unsigned long tx_reset_ic_bit;
 	unsigned long mmc_tx_irq_n;
 	unsigned long mmc_rx_irq_n;
 	unsigned long mmc_rx_csum_offload_irq_n;
@@ -162,6 +165,12 @@ struct stmmac_extra_stats {
 #define DMA_HW_FEAT_ACTPHYIF	0x70000000 /* Active/selected PHY interface */
 #define DEFAULT_DMA_PBL		8
 
+/* Tx coalesce parameters */
+#define STMMAC_COAL_TX_TIMER	40000
+#define STMMAC_MAX_COAL_TX_TICK	100000
+#define STMMAC_TX_MAX_FRAMES	256
+#define STMMAC_TX_FRAMES	64
+
 enum rx_frame_status { /* IPC status */
 	good_frame = 0,
 	discard_frame = 1,
@@ -169,10 +178,11 @@ enum rx_frame_status { /* IPC status */
 	llc_snap = 4,
 };
 
-enum tx_dma_irq_status {
-	tx_hard_error = 1,
-	tx_hard_error_bump_tc = 2,
-	handle_tx_rx = 3,
+enum dma_irq_status {
+	tx_hard_error = 0x1,
+	tx_hard_error_bump_tc = 0x2,
+	handle_rx = 0x4,
+	handle_tx = 0x8,
 };
 
 enum core_specific_irq_mask {
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c b/drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c
index 4e0e18a..73766e6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c
@@ -206,9 +206,10 @@ int dwmac_dma_interrupt(void __iomem *ioaddr,
 	/* TX/RX NORMAL interrupts */
 	if (intr_status & DMA_STATUS_NIS) {
 		x->normal_irq_n++;
-		if (likely((intr_status & DMA_STATUS_RI) ||
-			 (intr_status & (DMA_STATUS_TI))))
-				ret = handle_tx_rx;
+		if (likely(intr_status & DMA_STATUS_RI))
+			ret |= handle_rx;
+		if (intr_status & (DMA_STATUS_TI))
+			ret |= handle_tx;
 	}
 	/* Optional hardware blocks, interrupts should be disabled */
 	if (unlikely(intr_status &
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index 5f89415..01b3451 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -87,6 +87,10 @@ struct stmmac_priv {
 	int eee_enabled;
 	int eee_active;
 	int tx_lpi_timer;
+	struct timer_list txtimer;
+	u32 tx_count_frames;
+	u32 tx_coal_frames;
+	u32 tx_coal_timer;
 };
 
 extern int phyaddr;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
index 76fd61a..de2210c 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
@@ -90,10 +90,12 @@ static const struct stmmac_stats stmmac_gstrings_stats[] = {
 	STMMAC_STAT(threshold),
 	STMMAC_STAT(tx_pkt_n),
 	STMMAC_STAT(rx_pkt_n),
-	STMMAC_STAT(poll_n),
-	STMMAC_STAT(sched_timer_n),
-	STMMAC_STAT(normal_irq_n),
 	STMMAC_STAT(normal_irq_n),
+	STMMAC_STAT(rx_normal_irq_n),
+	STMMAC_STAT(napi_poll),
+	STMMAC_STAT(tx_normal_irq_n),
+	STMMAC_STAT(tx_clean),
+	STMMAC_STAT(tx_reset_ic_bit),
 	STMMAC_STAT(mmc_tx_irq_n),
 	STMMAC_STAT(mmc_rx_irq_n),
 	STMMAC_STAT(mmc_rx_csum_offload_irq_n),
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 777234c..d40cf9e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -137,6 +137,8 @@ static int stmmac_init_fs(struct net_device *dev);
 static void stmmac_exit_fs(void);
 #endif
 
+#define STMMAC_COAL_TIMER(x) (jiffies + usecs_to_jiffies(x))
+
 /**
  * stmmac_verify_args - verify the driver parameters.
  * Description: it verifies if some wrong parameter is passed to the driver.
@@ -688,16 +690,18 @@ static void stmmac_dma_operation_mode(struct stmmac_priv *priv)
 }
 
 /**
- * stmmac_tx:
- * @priv: private driver structure
+ * stmmac_tx_clean:
+ * @priv: private data pointer
  * Description: it reclaims resources after transmission completes.
  */
-static void stmmac_tx(struct stmmac_priv *priv)
+static void stmmac_tx_clean(struct stmmac_priv *priv)
 {
 	unsigned int txsize = priv->dma_tx_size;
 
 	spin_lock(&priv->tx_lock);
 
+	priv->xstats.tx_clean++;
+
 	while (priv->dirty_tx != priv->cur_tx) {
 		int last;
 		unsigned int entry = priv->dirty_tx % txsize;
@@ -757,40 +761,16 @@ static void stmmac_tx(struct stmmac_priv *priv)
 	spin_unlock(&priv->tx_lock);
 }
 
-static inline void stmmac_enable_irq(struct stmmac_priv *priv)
+static inline void stmmac_enable_dma_irq(struct stmmac_priv *priv)
 {
 	priv->hw->dma->enable_dma_irq(priv->ioaddr);
 }
 
-static inline void stmmac_disable_irq(struct stmmac_priv *priv)
+static inline void stmmac_disable_dma_irq(struct stmmac_priv *priv)
 {
 	priv->hw->dma->disable_dma_irq(priv->ioaddr);
 }
 
-static int stmmac_has_work(struct stmmac_priv *priv)
-{
-	unsigned int has_work = 0;
-	int rxret, tx_work = 0;
-
-	rxret = priv->hw->desc->get_rx_owner(priv->dma_rx +
-		(priv->cur_rx % priv->dma_rx_size));
-
-	if (priv->dirty_tx != priv->cur_tx)
-		tx_work = 1;
-
-	if (likely(!rxret || tx_work))
-		has_work = 1;
-
-	return has_work;
-}
-
-static inline void _stmmac_schedule(struct stmmac_priv *priv)
-{
-	if (likely(stmmac_has_work(priv))) {
-		stmmac_disable_irq(priv);
-		napi_schedule(&priv->napi);
-	}
-}
 
 /**
  * stmmac_tx_err:
@@ -813,16 +793,18 @@ static void stmmac_tx_err(struct stmmac_priv *priv)
 	netif_wake_queue(priv->dev);
 }
 
-
 static void stmmac_dma_interrupt(struct stmmac_priv *priv)
 {
 	int status;
 
 	status = priv->hw->dma->dma_interrupt(priv->ioaddr, &priv->xstats);
-	if (likely(status == handle_tx_rx))
-		_stmmac_schedule(priv);
-
-	else if (unlikely(status == tx_hard_error_bump_tc)) {
+	if (likely((status & handle_rx)) || (status & handle_tx)) {
+		if (likely(napi_schedule_prep(&priv->napi))) {
+			stmmac_disable_dma_irq(priv);
+			__napi_schedule(&priv->napi);
+		}
+	}
+	if (unlikely(status & tx_hard_error_bump_tc)) {
 		/* Try to bump up the dma threshold on this failure */
 		if (unlikely(tc != SF_DMA_MODE) && (tc <= 256)) {
 			tc += 64;
@@ -938,7 +920,6 @@ static int stmmac_get_hw_features(struct stmmac_priv *priv)
 		/* Alternate (enhanced) DESC mode*/
 		priv->dma_cap.enh_desc =
 			(hw_cap & DMA_HW_FEAT_ENHDESSEL) >> 24;
-
 	}
 
 	return hw_cap;
@@ -980,6 +961,38 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 }
 
 /**
+ * stmmac_tx_timer:
+ * @data: data pointer
+ * Description:
+ * This is the timer handler to directly invoke the stmmac_tx_clean.
+ */
+static void stmmac_tx_timer(unsigned long data)
+{
+	struct stmmac_priv *priv = (struct stmmac_priv *)data;
+
+	stmmac_tx_clean(priv);
+}
+
+/**
+ * stmmac_tx_timer:
+ * @priv: private data structure
+ * Description:
+ * This inits the transmit coalesce parameters: i.e. timer rate,
+ * timer handler and default threshold used for enabling the
+ * interrupt on completion bit.
+ */
+static void stmmac_init_tx_coalesce(struct stmmac_priv *priv)
+{
+	priv->tx_coal_frames = STMMAC_TX_FRAMES;
+	priv->tx_coal_timer = STMMAC_COAL_TX_TIMER;
+	init_timer(&priv->txtimer);
+	priv->txtimer.expires = STMMAC_COAL_TIMER(priv->tx_coal_timer);
+	priv->txtimer.data = (unsigned long)priv;
+	priv->txtimer.function = stmmac_tx_timer;
+	add_timer(&priv->txtimer);
+}
+
+/**
  *  stmmac_open - open entry point of the driver
  *  @dev : pointer to the device structure.
  *  Description:
@@ -1091,6 +1104,8 @@ static int stmmac_open(struct net_device *dev)
 	priv->tx_lpi_timer = STMMAC_DEFAULT_TWT_LS_TIMER;
 	priv->eee_enabled = stmmac_eee_init(priv);
 
+	stmmac_init_tx_coalesce(priv);
+
 	napi_enable(&priv->napi);
 	netif_start_queue(dev);
 
@@ -1136,6 +1151,8 @@ static int stmmac_release(struct net_device *dev)
 
 	napi_disable(&priv->napi);
 
+	del_timer_sync(&priv->txtimer);
+
 	/* Free the IRQ lines */
 	free_irq(dev->irq, dev);
 	if (priv->wol_irq != dev->irq)
@@ -1198,11 +1215,13 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 
 #ifdef STMMAC_XMIT_DEBUG
 	if ((skb->len > ETH_FRAME_LEN) || nfrags)
-		pr_info("stmmac xmit:\n"
-		       "\tskb addr %p - len: %d - nopaged_len: %d\n"
-		       "\tn_frags: %d - ip_summed: %d - %s gso\n",
-		       skb, skb->len, nopaged_len, nfrags, skb->ip_summed,
-		       !skb_is_gso(skb) ? "isn't" : "is");
+		pr_debug("stmmac xmit: [entry %d]\n"
+			 "\tskb addr %p - len: %d - nopaged_len: %d\n"
+			 "\tn_frags: %d - ip_summed: %d - %s gso\n"
+			 "\ttx_count_frames %d\n", entry,
+			 skb, skb->len, nopaged_len, nfrags, skb->ip_summed,
+			 !skb_is_gso(skb) ? "isn't" : "is",
+			 priv->tx_count_frames);
 #endif
 
 	csum_insertion = (skb->ip_summed == CHECKSUM_PARTIAL);
@@ -1212,9 +1231,9 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 
 #ifdef STMMAC_XMIT_DEBUG
 	if ((nfrags > 0) || (skb->len > ETH_FRAME_LEN))
-		pr_debug("stmmac xmit: skb len: %d, nopaged_len: %d,\n"
-		       "\t\tn_frags: %d, ip_summed: %d\n",
-		       skb->len, nopaged_len, nfrags, skb->ip_summed);
+		pr_debug("\tskb len: %d, nopaged_len: %d,\n"
+			 "\t\tn_frags: %d, ip_summed: %d\n",
+			 skb->len, nopaged_len, nfrags, skb->ip_summed);
 #endif
 	priv->tx_skbuff[entry] = skb;
 
@@ -1245,10 +1264,24 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 		wmb();
 	}
 
-	/* Interrupt on completition only for the latest segment */
+	/* Finalize the latest segment. */
 	priv->hw->desc->close_tx_desc(desc);
 
 	wmb();
+	/* According to the coalesce parameter the IC bit for the latest
+	 * segment could be reset and the timer re-started to invoke the
+	 * stmmac_tx function. This approach takes care about the fragments.
+	 */
+	priv->tx_count_frames += nfrags + 1;
+	if (priv->tx_coal_frames > priv->tx_count_frames) {
+		priv->hw->desc->clear_tx_ic(desc);
+		priv->xstats.tx_reset_ic_bit++;
+		TX_DBG("\t[entry %d]: tx_count_frames %d\n", entry,
+		       priv->tx_count_frames);
+		mod_timer(&priv->txtimer,
+			  STMMAC_COAL_TIMER(priv->tx_coal_timer));
+	} else
+		priv->tx_count_frames = 0;
 
 	/* To avoid raise condition */
 	priv->hw->desc->set_tx_owner(first);
@@ -1419,21 +1452,20 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit)
  *  @budget : maximum number of packets that the current CPU can receive from
  *	      all interfaces.
  *  Description :
- *   This function implements the the reception process.
- *   Also it runs the TX completion thread
+ *  To look at the incoming frames and clear the tx resources.
  */
 static int stmmac_poll(struct napi_struct *napi, int budget)
 {
 	struct stmmac_priv *priv = container_of(napi, struct stmmac_priv, napi);
 	int work_done = 0;
 
-	priv->xstats.poll_n++;
-	stmmac_tx(priv);
-	work_done = stmmac_rx(priv, budget);
+	priv->xstats.napi_poll++;
+	stmmac_tx_clean(priv);
 
+	work_done = stmmac_rx(priv, budget);
 	if (work_done < budget) {
 		napi_complete(napi);
-		stmmac_enable_irq(priv);
+		stmmac_enable_dma_irq(priv);
 	}
 	return work_done;
 }
-- 
1.7.4.4

[net-next.git 3/6 (V4)] stmmac: add Rx watchdog support to mitigate the DMA irqs

[Giuseppe CAVALLARO]

GMAC devices newer than databook 3.40 has an embedded timer
that can be used for mitigating the number of interrupts.
So this patch adds this optimizations.

At any rate, the Rx watchdog can be disable (on bugged HW) by
passing from the platform the riwt_off field.

In this implementation the rx timer stored in the Reg9 is fixed
to the max value. This will be tuned by using ethtool.

V2: added a platform parameter to force to disable the rx-watchdog
for example on new core where it is bugged.

V3: do not disable NAPI when Rx watchdog is used.

V4: a new extra statistic field has been added to show the early
receive status in the interrupt handler.
This patch also adds an extra check to avoid to call
napi_schedule when the DMA_INTR_ENA_RIE bit is disabled in the
Interrupt Mask register.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
---
 drivers/net/ethernet/stmicro/stmmac/common.h       |   17 +++++++++--
 drivers/net/ethernet/stmicro/stmmac/dwmac1000.h    |    3 --
 .../net/ethernet/stmicro/stmmac/dwmac1000_dma.c    |    6 ++++
 drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h    |    5 ++-
 drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c    |   19 ++++++++++--
 drivers/net/ethernet/stmicro/stmmac/stmmac.h       |    2 +
 .../net/ethernet/stmicro/stmmac/stmmac_ethtool.c   |    9 ++++--
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c  |   30 ++++++++++++++++----
 include/linux/stmmac.h                             |    1 +
 9 files changed, 72 insertions(+), 20 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
index d17eeef..98203f6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -48,6 +48,10 @@
 #define CHIP_DBG(fmt, args...)  do { } while (0)
 #endif
 
+/* Synopsys Core versions */
+#define	DWMAC_CORE_3_40	0x34
+#define	DWMAC_CORE_3_50	0x35
+
 #undef FRAME_FILTER_DEBUG
 /* #define FRAME_FILTER_DEBUG */
 
@@ -81,7 +85,7 @@ struct stmmac_extra_stats {
 	unsigned long rx_missed_cntr;
 	unsigned long rx_overflow_cntr;
 	unsigned long rx_vlan;
-	/* Tx/Rx IRQ errors */
+	/* Tx/Rx IRQ error info */
 	unsigned long tx_undeflow_irq;
 	unsigned long tx_process_stopped_irq;
 	unsigned long tx_jabber_irq;
@@ -91,7 +95,8 @@ struct stmmac_extra_stats {
 	unsigned long rx_watchdog_irq;
 	unsigned long tx_early_irq;
 	unsigned long fatal_bus_error_irq;
-	/* Extra info */
+	/* Tx/Rx IRQ Events */
+	unsigned long rx_early_irq;
 	unsigned long threshold;
 	unsigned long tx_pkt_n;
 	unsigned long rx_pkt_n;
@@ -101,11 +106,12 @@ struct stmmac_extra_stats {
 	unsigned long tx_normal_irq_n;
 	unsigned long tx_clean;
 	unsigned long tx_reset_ic_bit;
+	unsigned long irq_receive_pmt_irq_n;
+	/* MMC info */
 	unsigned long mmc_tx_irq_n;
 	unsigned long mmc_rx_irq_n;
 	unsigned long mmc_rx_csum_offload_irq_n;
 	/* EEE */
-	unsigned long irq_receive_pmt_irq_n;
 	unsigned long irq_tx_path_in_lpi_mode_n;
 	unsigned long irq_tx_path_exit_lpi_mode_n;
 	unsigned long irq_rx_path_in_lpi_mode_n;
@@ -165,6 +171,9 @@ struct stmmac_extra_stats {
 #define DMA_HW_FEAT_ACTPHYIF	0x70000000 /* Active/selected PHY interface */
 #define DEFAULT_DMA_PBL		8
 
+/* Max/Min RI Watchdog Timer count value */
+#define MAX_DMA_RIWT		0xff
+#define MIN_DMA_RIWT		0x20
 /* Tx coalesce parameters */
 #define STMMAC_COAL_TX_TIMER	40000
 #define STMMAC_MAX_COAL_TX_TICK	100000
@@ -306,6 +315,8 @@ struct stmmac_dma_ops {
 			      struct stmmac_extra_stats *x);
 	/* If supported then get the optional core features */
 	unsigned int (*get_hw_feature) (void __iomem *ioaddr);
+	/* Program the HW RX Watchdog */
+	void (*rx_watchdog) (void __iomem *ioaddr, u32 riwt);
 };
 
 struct stmmac_ops {
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000.h b/drivers/net/ethernet/stmicro/stmmac/dwmac1000.h
index 0e4cace..7ad56af 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000.h
@@ -230,8 +230,5 @@ enum rtc_control {
 #define GMAC_MMC_TX_INTR   0x108
 #define GMAC_MMC_RX_CSUM_OFFLOAD   0x208
 
-/* Synopsys Core versions */
-#define	DWMAC_CORE_3_40	0x34
-
 extern const struct stmmac_dma_ops dwmac1000_dma_ops;
 #endif /* __DWMAC1000_H__ */
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
index 0335000..bf83c03 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
@@ -174,6 +174,11 @@ static unsigned int dwmac1000_get_hw_feature(void __iomem *ioaddr)
 	return readl(ioaddr + DMA_HW_FEATURE);
 }
 
+static void dwmac1000_rx_watchdog(void __iomem *ioaddr, u32 riwt)
+{
+	writel(riwt, ioaddr + DMA_RX_WATCHDOG);
+}
+
 const struct stmmac_dma_ops dwmac1000_dma_ops = {
 	.init = dwmac1000_dma_init,
 	.dump_regs = dwmac1000_dump_dma_regs,
@@ -187,4 +192,5 @@ const struct stmmac_dma_ops dwmac1000_dma_ops = {
 	.stop_rx = dwmac_dma_stop_rx,
 	.dma_interrupt = dwmac_dma_interrupt,
 	.get_hw_feature = dwmac1000_get_hw_feature,
+	.rx_watchdog = dwmac1000_rx_watchdog,
 };
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h b/drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h
index e49c9a0..807f303 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h
@@ -35,7 +35,10 @@
 #define DMA_CONTROL		0x00001018	/* Ctrl (Operational Mode) */
 #define DMA_INTR_ENA		0x0000101c	/* Interrupt Enable */
 #define DMA_MISSED_FRAME_CTR	0x00001020	/* Missed Frame Counter */
-#define DMA_AXI_BUS_MODE       0x00001028      /* AXI Bus Mode */
+/* Rx watchdog register */
+#define DMA_RX_WATCHDOG		0x00001024
+/* AXI Bus Mode */
+#define DMA_AXI_BUS_MODE	0x00001028
 #define DMA_CUR_TX_BUF_ADDR	0x00001050	/* Current Host Tx Buffer */
 #define DMA_CUR_RX_BUF_ADDR	0x00001054	/* Current Host Rx Buffer */
 #define DMA_HW_FEATURE		0x00001058	/* HW Feature Register */
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c b/drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c
index 73766e6..491d7e9 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c
@@ -204,17 +204,28 @@ int dwmac_dma_interrupt(void __iomem *ioaddr,
 		}
 	}
 	/* TX/RX NORMAL interrupts */
-	if (intr_status & DMA_STATUS_NIS) {
+	if (likely(intr_status & DMA_STATUS_NIS)) {
 		x->normal_irq_n++;
-		if (likely(intr_status & DMA_STATUS_RI))
-			ret |= handle_rx;
-		if (intr_status & (DMA_STATUS_TI))
+		if (likely(intr_status & DMA_STATUS_RI)) {
+			u32 value = readl(ioaddr + DMA_INTR_ENA);
+			/* to schedule NAPI on real RIE event. */
+			if (likely(value & DMA_INTR_ENA_RIE)) {
+				x->rx_normal_irq_n++;
+				ret |= handle_rx;
+			}
+		}
+		if (likely(intr_status & DMA_STATUS_TI)) {
+			x->tx_normal_irq_n++;
 			ret |= handle_tx;
+		}
+		if (unlikely(intr_status & DMA_STATUS_ERI))
+			x->rx_early_irq++;
 	}
 	/* Optional hardware blocks, interrupts should be disabled */
 	if (unlikely(intr_status &
 		     (DMA_STATUS_GPI | DMA_STATUS_GMI | DMA_STATUS_GLI)))
 		pr_info("%s: unexpected status %08x\n", __func__, intr_status);
+
 	/* Clear the interrupt by writing a logic 1 to the CSR5[15-0] */
 	writel((intr_status & 0x1ffff), ioaddr + DMA_STATUS);
 
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index 01b3451..fe0535c 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -91,6 +91,8 @@ struct stmmac_priv {
 	u32 tx_count_frames;
 	u32 tx_coal_frames;
 	u32 tx_coal_timer;
+	int use_riwt;
+	u32 rx_riwt;
 };
 
 extern int phyaddr;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
index de2210c..240acd2 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
@@ -76,7 +76,7 @@ static const struct stmmac_stats stmmac_gstrings_stats[] = {
 	STMMAC_STAT(rx_missed_cntr),
 	STMMAC_STAT(rx_overflow_cntr),
 	STMMAC_STAT(rx_vlan),
-	/* Tx/Rx IRQ errors */
+	/* Tx/Rx IRQ error info */
 	STMMAC_STAT(tx_undeflow_irq),
 	STMMAC_STAT(tx_process_stopped_irq),
 	STMMAC_STAT(tx_jabber_irq),
@@ -86,7 +86,8 @@ static const struct stmmac_stats stmmac_gstrings_stats[] = {
 	STMMAC_STAT(rx_watchdog_irq),
 	STMMAC_STAT(tx_early_irq),
 	STMMAC_STAT(fatal_bus_error_irq),
-	/* Extra info */
+	/* Tx/Rx IRQ Events */
+	STMMAC_STAT(rx_early_irq),
 	STMMAC_STAT(threshold),
 	STMMAC_STAT(tx_pkt_n),
 	STMMAC_STAT(rx_pkt_n),
@@ -96,10 +97,12 @@ static const struct stmmac_stats stmmac_gstrings_stats[] = {
 	STMMAC_STAT(tx_normal_irq_n),
 	STMMAC_STAT(tx_clean),
 	STMMAC_STAT(tx_reset_ic_bit),
+	STMMAC_STAT(irq_receive_pmt_irq_n),
+	/* MMC info */
 	STMMAC_STAT(mmc_tx_irq_n),
 	STMMAC_STAT(mmc_rx_irq_n),
 	STMMAC_STAT(mmc_rx_csum_offload_irq_n),
-	STMMAC_STAT(irq_receive_pmt_irq_n),
+	/* EEE */
 	STMMAC_STAT(irq_tx_path_in_lpi_mode_n),
 	STMMAC_STAT(irq_tx_path_exit_lpi_mode_n),
 	STMMAC_STAT(irq_rx_path_in_lpi_mode_n),
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index d40cf9e..2fb0e5f 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -603,6 +603,8 @@ static void init_dma_desc_rings(struct net_device *dev)
 	priv->dirty_tx = 0;
 	priv->cur_tx = 0;
 
+	if (priv->use_riwt)
+		dis_ic = 1;
 	/* Clear the Rx/Tx descriptors */
 	priv->hw->desc->init_rx_desc(priv->dma_rx, rxsize, dis_ic);
 	priv->hw->desc->init_tx_desc(priv->dma_tx, txsize);
@@ -1106,6 +1108,11 @@ static int stmmac_open(struct net_device *dev)
 
 	stmmac_init_tx_coalesce(priv);
 
+	if ((priv->use_riwt) && (priv->hw->dma->rx_watchdog)) {
+		priv->rx_riwt = MAX_DMA_RIWT;
+		priv->hw->dma->rx_watchdog(priv->ioaddr, MAX_DMA_RIWT);
+	}
+
 	napi_enable(&priv->napi);
 	netif_start_queue(dev);
 
@@ -1423,14 +1430,12 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit)
 #endif
 			skb->protocol = eth_type_trans(skb, priv->dev);
 
-			if (unlikely(!priv->plat->rx_coe)) {
-				/* No RX COE for old mac10/100 devices */
+			if (unlikely(!priv->plat->rx_coe))
 				skb_checksum_none_assert(skb);
-				netif_receive_skb(skb);
-			} else {
+			else
 				skb->ip_summed = CHECKSUM_UNNECESSARY;
-				napi_gro_receive(&priv->napi, skb);
-			}
+
+			napi_gro_receive(&priv->napi, skb);
 
 			priv->dev->stats.rx_packets++;
 			priv->dev->stats.rx_bytes += frame_len;
@@ -2001,6 +2006,16 @@ struct stmmac_priv *stmmac_dvr_probe(struct device *device,
 	if (flow_ctrl)
 		priv->flow_ctrl = FLOW_AUTO;	/* RX/TX pause on */
 
+	/* Rx Watchdog is available in the COREs newer than the 3.40.
+	 * In some case, for example on bugged HW this feature
+	 * has to be disable and this can be done by passing the
+	 * riwt_off field from the platform.
+	 */
+	if ((priv->synopsys_id >= DWMAC_CORE_3_50) && (!priv->plat->riwt_off)) {
+		priv->use_riwt = 1;
+		pr_info(" Enable RX Mitigation via HW Watchdog Timer\n");
+	}
+
 	netif_napi_add(ndev, &priv->napi, stmmac_poll, 64);
 
 	spin_lock_init(&priv->lock);
@@ -2092,6 +2107,9 @@ int stmmac_suspend(struct net_device *ndev)
 	netif_device_detach(ndev);
 	netif_stop_queue(ndev);
 
+	if (priv->use_riwt)
+		dis_ic = 1;
+
 	napi_disable(&priv->napi);
 
 	/* Stop TX/RX DMA */
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index a1547ea..de5b2f8 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -104,6 +104,7 @@ struct plat_stmmacenet_data {
 	int bugged_jumbo;
 	int pmt;
 	int force_sf_dma_mode;
+	int riwt_off;
 	void (*fix_mac_speed)(void *priv, unsigned int speed);
 	void (*bus_setup)(void __iomem *ioaddr);
 	int (*init)(struct platform_device *pdev);
-- 
1.7.4.4

[net-next.git 4/6 (V2)] stmmac: get/set coalesce parameters via ethtool

[Giuseppe CAVALLARO]

This patch is to get/set the tx/rx coalesce parameters
via ethtool interface.

Tests have been done on several platform with different GMAC chips w/o and w/
RX watchdog feature.

V2: reject coalesce settings that are not supported.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Reviewed-by: Ben Hutchings <bhutchings@solarflare.com>
---
 .../net/ethernet/stmicro/stmmac/stmmac_ethtool.c   |   83 ++++++++++++++++++++
 1 files changed, 83 insertions(+), 0 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
index 240acd2..f2aa013 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
@@ -524,6 +524,87 @@ static int stmmac_ethtool_op_set_eee(struct net_device *dev,
 	return phy_ethtool_set_eee(priv->phydev, edata);
 }
 
+static u32 stmmac_usec2riwt(u32 usec, struct stmmac_priv *priv)
+{
+	unsigned long clk = clk_get_rate(priv->stmmac_clk);
+
+	if (!clk)
+		return 0;
+
+	return (usec * (clk / 1000000)) / 256;
+}
+
+static u32 stmmac_riwt2usec(u32 riwt, struct stmmac_priv *priv)
+{
+	unsigned long clk = clk_get_rate(priv->stmmac_clk);
+
+	if (!clk)
+		return 0;
+
+	return (riwt * 256) / (clk / 1000000);
+}
+
+static int stmmac_get_coalesce(struct net_device *dev,
+			       struct ethtool_coalesce *ec)
+{
+	struct stmmac_priv *priv = netdev_priv(dev);
+
+	ec->tx_coalesce_usecs = priv->tx_coal_timer;
+	ec->tx_max_coalesced_frames = priv->tx_coal_frames;
+
+	if (priv->use_riwt)
+		ec->rx_coalesce_usecs = stmmac_riwt2usec(priv->rx_riwt, priv);
+
+	return 0;
+}
+
+static int stmmac_set_coalesce(struct net_device *dev,
+			       struct ethtool_coalesce *ec)
+{
+	struct stmmac_priv *priv = netdev_priv(dev);
+	unsigned int rx_riwt;
+
+	/* Check not supported parameters  */
+	if ((ec->rx_max_coalesced_frames) || (ec->rx_coalesce_usecs_irq) ||
+	    (ec->rx_max_coalesced_frames_irq) || (ec->tx_coalesce_usecs_irq) ||
+	    (ec->use_adaptive_rx_coalesce) || (ec->use_adaptive_tx_coalesce) ||
+	    (ec->pkt_rate_low) || (ec->rx_coalesce_usecs_low) ||
+	    (ec->rx_max_coalesced_frames_low) || (ec->tx_coalesce_usecs_high) ||
+	    (ec->tx_max_coalesced_frames_low) || (ec->pkt_rate_high) ||
+	    (ec->tx_coalesce_usecs_low) || (ec->rx_coalesce_usecs_high) ||
+	    (ec->rx_max_coalesced_frames_high) ||
+	    (ec->tx_max_coalesced_frames_irq) ||
+	    (ec->stats_block_coalesce_usecs) ||
+	    (ec->tx_max_coalesced_frames_high) || (ec->rate_sample_interval))
+		return -EOPNOTSUPP;
+
+	if (ec->rx_coalesce_usecs == 0)
+		return -EINVAL;
+
+	if ((ec->tx_coalesce_usecs == 0) &&
+	    (ec->tx_max_coalesced_frames == 0))
+		return -EINVAL;
+
+	if ((ec->tx_coalesce_usecs > STMMAC_COAL_TX_TIMER) ||
+	    (ec->tx_max_coalesced_frames > STMMAC_TX_MAX_FRAMES))
+		return -EINVAL;
+
+	rx_riwt = stmmac_usec2riwt(ec->rx_coalesce_usecs, priv);
+
+	if ((rx_riwt > MAX_DMA_RIWT) || (rx_riwt < MIN_DMA_RIWT))
+		return -EINVAL;
+	else if (!priv->use_riwt)
+		return -EOPNOTSUPP;
+
+	/* Only copy relevant parameters, ignore all others. */
+	priv->tx_coal_frames = ec->tx_max_coalesced_frames;
+	priv->tx_coal_timer = ec->tx_coalesce_usecs;
+	priv->rx_riwt = rx_riwt;
+	priv->hw->dma->rx_watchdog(priv->ioaddr, priv->rx_riwt);
+
+	return 0;
+}
+
 static const struct ethtool_ops stmmac_ethtool_ops = {
 	.begin = stmmac_check_if_running,
 	.get_drvinfo = stmmac_ethtool_getdrvinfo,
@@ -544,6 +625,8 @@ static const struct ethtool_ops stmmac_ethtool_ops = {
 	.set_eee = stmmac_ethtool_op_set_eee,
 	.get_sset_count	= stmmac_get_sset_count,
 	.get_ts_info = ethtool_op_get_ts_info,
+	.get_coalesce = stmmac_get_coalesce,
+	.set_coalesce = stmmac_set_coalesce,
 };
 
 void stmmac_set_ethtool_ops(struct net_device *netdev)
-- 
1.7.4.4

[net-next.git 5/6] stmmac: update the doc with new IRQ mitigation

[Giuseppe CAVALLARO]

This patch updates the stmmac.txt adding some information
about the new rx/tx mitigation schema adopted in the driver.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
---
 Documentation/networking/stmmac.txt |   28 +++++++++++++++-------------
 1 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/Documentation/networking/stmmac.txt b/Documentation/networking/stmmac.txt
index ef9ee71..f9fa6db 100644
--- a/Documentation/networking/stmmac.txt
+++ b/Documentation/networking/stmmac.txt
@@ -29,11 +29,9 @@ The kernel configuration option is STMMAC_ETH:
 	dma_txsize: DMA tx ring size;
 	buf_sz: DMA buffer size;
 	tc: control the HW FIFO threshold;
-	tx_coe: Enable/Disable Tx Checksum Offload engine;
 	watchdog: transmit timeout (in milliseconds);
 	flow_ctrl: Flow control ability [on/off];
 	pause: Flow Control Pause Time;
-	tmrate: timer period (only if timer optimisation is configured).
 
 3) Command line options
 Driver parameters can be also passed in command line by using:
@@ -60,17 +58,19 @@ Then the poll method will be scheduled at some future point.
 The incoming packets are stored, by the DMA, in a list of pre-allocated socket
 buffers in order to avoid the memcpy (Zero-copy).
 
-4.3) Timer-Driver Interrupt
-Instead of having the device that asynchronously notifies the frame receptions,
-the driver configures a timer to generate an interrupt at regular intervals.
-Based on the granularity of the timer, the frames that are received by the
-device will experience different levels of latency. Some NICs have dedicated
-timer device to perform this task. STMMAC can use either the RTC device or the
-TMU channel 2  on STLinux platforms.
-The timers frequency can be passed to the driver as parameter; when change it,
-take care of both hardware capability and network stability/performance impact.
-Several performance tests on STM platforms showed this optimisation allows to
-spare the CPU while having the maximum throughput.
+4.3) Interrupt Mitigation
+The driver is able to mitigate the number of its DMA interrupts
+using NAPI for the reception on chips older than the 3.50.
+New chips have an HW RX-Watchdog used for this mitigation.
+
+On Tx-side, the mitigation schema is based on a SW timer that calls the
+tx function (stmmac_tx) to reclaim the resource after transmitting the
+frames.
+Also there is another parameter (like a threshold) used to program
+the descriptors avoiding to set the interrupt on completion bit in
+when the frame is sent (xmit).
+
+Mitigation parameters can be tuned by ethtool.
 
 4.4) WOL
 Wake up on Lan feature through Magic and Unicast frames are supported for the
@@ -121,6 +121,7 @@ struct plat_stmmacenet_data {
 	int bugged_jumbo;
 	int pmt;
 	int force_sf_dma_mode;
+	int riwt_off;
 	void (*fix_mac_speed)(void *priv, unsigned int speed);
 	void (*bus_setup)(void __iomem *ioaddr);
 	int (*init)(struct platform_device *pdev);
@@ -156,6 +157,7 @@ Where:
  o pmt: core has the embedded power module (optional).
  o force_sf_dma_mode: force DMA to use the Store and Forward mode
 		     instead of the Threshold.
+ o riwt_off: force to disable the RX watchdog feature and switch to NAPI mode.
  o fix_mac_speed: this callback is used for modifying some syscfg registers
 		 (on ST SoCs) according to the link speed negotiated by the
 		 physical layer .
-- 
1.7.4.4

[net-next.git 6/6] stmmac: update the driver version to Nov_2012

[Giuseppe CAVALLARO]

Many new feauture have been introduced in the driver:
ethtool coalesce options, Rx HW watchdog... so this patch updates the
driver's version.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index fe0535c..023a4fb 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -24,7 +24,7 @@
 #define __STMMAC_H__
 
 #define STMMAC_RESOURCE_NAME   "stmmaceth"
-#define DRV_MODULE_VERSION	"March_2012"
+#define DRV_MODULE_VERSION	"Nov_2012"
 
 #include <linux/clk.h>
 #include <linux/stmmac.h>
-- 
1.7.4.4

Re: [net-next.git 0/6 (V5)] stmmac: remove dead code for STMMAC_TIMER and add new mitigation schema

[David Miller]

From: Giuseppe CAVALLARO <peppe.cavallaro@st.com>
Date: Mon, 26 Nov 2012 10:10:40 +0100

> These patch series remove the STMMAC_TIMER option no longer updated
> and never used and add a new mitigation schema.
> Having removed the Timer opt, this has made the driver slim.
> On top of this work, it has been easier to introduce the new
> mitigation schema based on HW RX-watchdog (available in new cores).
> In fact, 3.50 and newer cores have an HW RX-Watchdog that can be used for 
> mitigating the Rx-interrupts and first results look promising.

All applied to net-next