[PATCH 3/9] net: ethernet: ti: cpts: rework initialization/deinitialization

[Grygorii Strashko]

The current implementation CPTS initialization and deinitialization
(represented by cpts_register/unregister()) is pretty entangled and
has some issues, like:
- ptp clock registered before spinlock, which is protecting it, and
before timecounter and cyclecounter initialization;
- CPTS ref_clk requested using devm API while cpts_register() is
called from .ndo_open(), as result additional checks required;
- CPTS ref_clk is prepared, but never unprepared;
- CPTS is not disabled even when unregistered..

Hence, make things simpler and fix above issues by adding
cpts_create()/cpts_release() which should be called from
.probe()/.remove() respectively and move all static initialization
there. Clean up and update cpts_register/unregister() so PTP clock is
registered the last and unregistered first. In addition, this change
allows to clean up cpts.h for the case when CPTS is disabled.

Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
---
 drivers/net/ethernet/ti/cpsw.c |  24 ++++----
 drivers/net/ethernet/ti/cpts.c | 125 ++++++++++++++++++++++++++---------------
 drivers/net/ethernet/ti/cpts.h |  26 +++++++--
 3 files changed, 113 insertions(+), 62 deletions(-)

diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index 9b900f0..dfd5707 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -1406,9 +1406,7 @@ static int cpsw_ndo_open(struct net_device *ndev)
 		if (ret < 0)
 			goto err_cleanup;
 
-		if (cpts_register(cpsw->dev, cpsw->cpts,
-				  cpsw->data.cpts_clock_mult,
-				  cpsw->data.cpts_clock_shift))
+		if (cpts_register(cpsw->cpts))
 			dev_err(priv->dev, "error registering cpts device\n");
 
 	}
@@ -2551,6 +2549,7 @@ static int cpsw_probe(struct platform_device *pdev)
 	struct cpdma_params		dma_params;
 	struct cpsw_ale_params		ale_params;
 	void __iomem			*ss_regs;
+	void __iomem			*cpts_regs;
 	struct resource			*res, *ss_res;
 	const struct of_device_id	*of_id;
 	struct gpio_descs		*mode;
@@ -2575,12 +2574,6 @@ static int cpsw_probe(struct platform_device *pdev)
 	priv->dev  = &ndev->dev;
 	priv->msg_enable = netif_msg_init(debug_level, CPSW_DEBUG);
 	cpsw->rx_packet_max = max(rx_packet_max, 128);
-	cpsw->cpts = devm_kzalloc(&pdev->dev, sizeof(struct cpts), GFP_KERNEL);
-	if (!cpsw->cpts) {
-		dev_err(&pdev->dev, "error allocating cpts\n");
-		ret = -ENOMEM;
-		goto clean_ndev_ret;
-	}
 
 	mode = devm_gpiod_get_array_optional(&pdev->dev, "mode", GPIOD_OUT_LOW);
 	if (IS_ERR(mode)) {
@@ -2669,7 +2662,7 @@ static int cpsw_probe(struct platform_device *pdev)
 	switch (cpsw->version) {
 	case CPSW_VERSION_1:
 		cpsw->host_port_regs = ss_regs + CPSW1_HOST_PORT_OFFSET;
-		cpsw->cpts->reg      = ss_regs + CPSW1_CPTS_OFFSET;
+		cpts_regs		= ss_regs + CPSW1_CPTS_OFFSET;
 		cpsw->hw_stats	     = ss_regs + CPSW1_HW_STATS;
 		dma_params.dmaregs   = ss_regs + CPSW1_CPDMA_OFFSET;
 		dma_params.txhdp     = ss_regs + CPSW1_STATERAM_OFFSET;
@@ -2683,7 +2676,7 @@ static int cpsw_probe(struct platform_device *pdev)
 	case CPSW_VERSION_3:
 	case CPSW_VERSION_4:
 		cpsw->host_port_regs = ss_regs + CPSW2_HOST_PORT_OFFSET;
-		cpsw->cpts->reg      = ss_regs + CPSW2_CPTS_OFFSET;
+		cpts_regs		= ss_regs + CPSW2_CPTS_OFFSET;
 		cpsw->hw_stats	     = ss_regs + CPSW2_HW_STATS;
 		dma_params.dmaregs   = ss_regs + CPSW2_CPDMA_OFFSET;
 		dma_params.txhdp     = ss_regs + CPSW2_STATERAM_OFFSET;
@@ -2749,6 +2742,14 @@ static int cpsw_probe(struct platform_device *pdev)
 		goto clean_dma_ret;
 	}
 
+	cpsw->cpts = cpts_create(cpsw->dev, cpts_regs,
+				 cpsw->data.cpts_clock_mult,
+				 cpsw->data.cpts_clock_shift);
+	if (IS_ERR(cpsw->cpts)) {
+		ret = PTR_ERR(cpsw->cpts);
+		goto clean_ale_ret;
+	}
+
 	ndev->irq = platform_get_irq(pdev, 1);
 	if (ndev->irq < 0) {
 		dev_err(priv->dev, "error getting irq resource\n");
@@ -2857,6 +2858,7 @@ static int cpsw_remove(struct platform_device *pdev)
 		unregister_netdev(cpsw->slaves[1].ndev);
 	unregister_netdev(ndev);
 
+	cpts_release(cpsw->cpts);
 	cpsw_ale_destroy(cpsw->ale);
 	cpdma_ctlr_destroy(cpsw->dma);
 	of_platform_depopulate(&pdev->dev);
diff --git a/drivers/net/ethernet/ti/cpts.c b/drivers/net/ethernet/ti/cpts.c
index aaab08e..a46478e 100644
--- a/drivers/net/ethernet/ti/cpts.c
+++ b/drivers/net/ethernet/ti/cpts.c
@@ -228,22 +228,6 @@ static void cpts_overflow_check(struct work_struct *work)
 	schedule_delayed_work(&cpts->overflow_work, CPTS_OVERFLOW_PERIOD);
 }
 
-static void cpts_clk_init(struct device *dev, struct cpts *cpts)
-{
-	cpts->refclk = devm_clk_get(dev, "cpts");
-	if (IS_ERR(cpts->refclk)) {
-		dev_err(dev, "Failed to get cpts refclk\n");
-		cpts->refclk = NULL;
-		return;
-	}
-	clk_prepare_enable(cpts->refclk);
-}
-
-static void cpts_clk_release(struct cpts *cpts)
-{
-	clk_disable(cpts->refclk);
-}
-
 static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
 		      u16 ts_seqid, u8 ts_msgtype)
 {
@@ -323,7 +307,7 @@ void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 	u64 ns;
 	struct skb_shared_hwtstamps *ssh;
 
-	if (!cpts->rx_enable)
+	if (!cpts || !cpts->rx_enable)
 		return;
 	ns = cpts_find_ts(cpts, skb, CPTS_EV_RX);
 	if (!ns)
@@ -338,7 +322,7 @@ void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 	u64 ns;
 	struct skb_shared_hwtstamps ssh;
 
-	if (!(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
+	if (!cpts || !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
 		return;
 	ns = cpts_find_ts(cpts, skb, CPTS_EV_TX);
 	if (!ns)
@@ -348,53 +332,102 @@ void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 	skb_tstamp_tx(skb, &ssh);
 }
 
-int cpts_register(struct device *dev, struct cpts *cpts,
-		  u32 mult, u32 shift)
+int cpts_register(struct cpts *cpts)
 {
 	int err, i;
-	unsigned long flags;
 
-	cpts->info = cpts_info;
-	cpts->clock = ptp_clock_register(&cpts->info, dev);
-	if (IS_ERR(cpts->clock)) {
-		err = PTR_ERR(cpts->clock);
-		cpts->clock = NULL;
-		return err;
-	}
-	spin_lock_init(&cpts->lock);
-
-	cpts->cc.read = cpts_systim_read;
-	cpts->cc.mask = CLOCKSOURCE_MASK(32);
-	cpts->cc_mult = mult;
-	cpts->cc.mult = mult;
-	cpts->cc.shift = shift;
+	if (!cpts)
+		return -EINVAL;
 
 	INIT_LIST_HEAD(&cpts->events);
 	INIT_LIST_HEAD(&cpts->pool);
 	for (i = 0; i < CPTS_MAX_EVENTS; i++)
 		list_add(&cpts->pool_data[i].list, &cpts->pool);
 
-	cpts_clk_init(dev, cpts);
+	clk_enable(cpts->refclk);
+
 	cpts_write32(cpts, CPTS_EN, control);
 	cpts_write32(cpts, TS_PEND_EN, int_enable);
 
-	spin_lock_irqsave(&cpts->lock, flags);
+	cpts->cc.mult = cpts->cc_mult;
 	timecounter_init(&cpts->tc, &cpts->cc, ktime_to_ns(ktime_get_real()));
-	spin_unlock_irqrestore(&cpts->lock, flags);
-
-	INIT_DELAYED_WORK(&cpts->overflow_work, cpts_overflow_check);
-	schedule_delayed_work(&cpts->overflow_work, CPTS_OVERFLOW_PERIOD);
 
+	cpts->info = cpts_info;
+	cpts->clock = ptp_clock_register(&cpts->info, cpts->dev);
+	if (IS_ERR(cpts->clock)) {
+		err = PTR_ERR(cpts->clock);
+		cpts->clock = NULL;
+		goto err_ptp;
+	}
 	cpts->phc_index = ptp_clock_index(cpts->clock);
+
+	schedule_delayed_work(&cpts->overflow_work, CPTS_OVERFLOW_PERIOD);
 	return 0;
+
+err_ptp:
+	clk_disable(cpts->refclk);
+	return err;
 }
 
 void cpts_unregister(struct cpts *cpts)
 {
-	if (cpts->clock) {
-		ptp_clock_unregister(cpts->clock);
-		cancel_delayed_work_sync(&cpts->overflow_work);
+	if (!cpts)
+		return;
+
+	if (WARN_ON(!cpts->clock))
+		return;
+
+	cancel_delayed_work_sync(&cpts->overflow_work);
+
+	ptp_clock_unregister(cpts->clock);
+	cpts->clock = NULL;
+
+	cpts_write32(cpts, 0, int_enable);
+	cpts_write32(cpts, 0, control);
+
+	clk_disable(cpts->refclk);
+}
+
+struct cpts *cpts_create(struct device *dev, void __iomem *regs,
+			 u32 mult, u32 shift)
+{
+	struct cpts *cpts;
+
+	if (!regs || !dev)
+		return ERR_PTR(-EINVAL);
+
+	cpts = devm_kzalloc(dev, sizeof(*cpts), GFP_KERNEL);
+	if (!cpts)
+		return ERR_PTR(-ENOMEM);
+
+	cpts->dev = dev;
+	cpts->reg = (struct cpsw_cpts __iomem *)regs;
+	spin_lock_init(&cpts->lock);
+	INIT_DELAYED_WORK(&cpts->overflow_work, cpts_overflow_check);
+
+	cpts->refclk = devm_clk_get(dev, "cpts");
+	if (IS_ERR(cpts->refclk)) {
+		dev_err(dev, "Failed to get cpts refclk\n");
+		return ERR_PTR(PTR_ERR(cpts->refclk));
 	}
-	if (cpts->refclk)
-		cpts_clk_release(cpts);
+
+	clk_prepare(cpts->refclk);
+
+	cpts->cc.read = cpts_systim_read;
+	cpts->cc.mask = CLOCKSOURCE_MASK(32);
+	cpts->cc.shift = shift;
+	cpts->cc_mult = mult;
+
+	return cpts;
+}
+
+void cpts_release(struct cpts *cpts)
+{
+	if (!cpts)
+		return;
+
+	if (!cpts->refclk)
+		return;
+
+	clk_unprepare(cpts->refclk);
 }
diff --git a/drivers/net/ethernet/ti/cpts.h b/drivers/net/ethernet/ti/cpts.h
index fec753c..0c02f48 100644
--- a/drivers/net/ethernet/ti/cpts.h
+++ b/drivers/net/ethernet/ti/cpts.h
@@ -20,6 +20,8 @@
 #ifndef _TI_CPTS_H_
 #define _TI_CPTS_H_
 
+#ifdef CONFIG_TI_CPTS
+
 #include <linux/clk.h>
 #include <linux/clkdev.h>
 #include <linux/clocksource.h>
@@ -108,10 +110,10 @@ struct cpts_event {
 };
 
 struct cpts {
+	struct device *dev;
 	struct cpsw_cpts __iomem *reg;
 	int tx_enable;
 	int rx_enable;
-#ifdef CONFIG_TI_CPTS
 	struct ptp_clock_info info;
 	struct ptp_clock *clock;
 	spinlock_t lock; /* protects time registers */
@@ -124,14 +126,15 @@ struct cpts {
 	struct list_head events;
 	struct list_head pool;
 	struct cpts_event pool_data[CPTS_MAX_EVENTS];
-#endif
 };
 
-#ifdef CONFIG_TI_CPTS
 void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb);
 void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb);
-int cpts_register(struct device *dev, struct cpts *cpts, u32 mult, u32 shift);
+int cpts_register(struct cpts *cpts);
 void cpts_unregister(struct cpts *cpts);
+struct cpts *cpts_create(struct device *dev, void __iomem *regs,
+			 u32 mult, u32 shift);
+void cpts_release(struct cpts *cpts);
 
 static inline void cpts_rx_enable(struct cpts *cpts, int enable)
 {
@@ -156,6 +159,8 @@ static inline bool cpts_is_tx_enabled(struct cpts *cpts)
 }
 
 #else
+struct cpts;
+
 static inline void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 {
 }
@@ -163,8 +168,19 @@ static inline void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 {
 }
 
+static inline
+struct cpts *cpts_create(struct device *dev, void __iomem *regs,
+			 u32 mult, u32 shift)
+{
+	return NULL;
+}
+
+static inline void cpts_release(struct cpts *cpts)
+{
+}
+
 static inline int
-cpts_register(struct device *dev, struct cpts *cpts, u32 mult, u32 shift)
+cpts_register(struct cpts *cpts)
 {
 	return 0;
 }
-- 
2.9.3