From 6a792e8158a2597418a0833c7e350328e209f318 Mon Sep 17 00:00:00 2001 From: Quentin Schulz Date: Fri, 5 May 2017 15:50:30 +0200 Subject: [PATCH 1/4] can: m_can: move Message RAM initialization to function To avoid possible ECC/parity checksum errors when reading an uninitialized buffer, the entire Message RAM is initialized when probing the driver. This initialization is done in the same function reading the Device Tree properties. This patch moves the RAM initialization to a separate function so it can be called separately from device initialization from Device Tree. Signed-off-by: Quentin Schulz Signed-off-by: Marc Kleine-Budde --- drivers/net/can/m_can/m_can.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index bf8fdaeb955e..5da1bdb202a3 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1489,11 +1489,23 @@ static int register_m_can_dev(struct net_device *dev) return register_candev(dev); } +static void m_can_init_ram(struct m_can_priv *priv) +{ + int end, i, start; + + /* initialize the entire Message RAM in use to avoid possible + * ECC/parity checksum errors when reading an uninitialized buffer + */ + start = priv->mcfg[MRAM_SIDF].off; + end = priv->mcfg[MRAM_TXB].off + + priv->mcfg[MRAM_TXB].num * TXB_ELEMENT_SIZE; + for (i = start; i < end; i += 4) + writel(0x0, priv->mram_base + i); +} + static void m_can_of_parse_mram(struct m_can_priv *priv, const u32 *mram_config_vals) { - int i, start, end; - priv->mcfg[MRAM_SIDF].off = mram_config_vals[0]; priv->mcfg[MRAM_SIDF].num = mram_config_vals[1]; priv->mcfg[MRAM_XIDF].off = priv->mcfg[MRAM_SIDF].off + @@ -1529,15 +1541,7 @@ static void m_can_of_parse_mram(struct m_can_priv *priv, priv->mcfg[MRAM_TXE].off, priv->mcfg[MRAM_TXE].num, priv->mcfg[MRAM_TXB].off, priv->mcfg[MRAM_TXB].num); - /* initialize the entire Message RAM in use to avoid possible - * ECC/parity checksum errors when reading an uninitialized buffer - */ - start = priv->mcfg[MRAM_SIDF].off; - end = priv->mcfg[MRAM_TXB].off + - priv->mcfg[MRAM_TXB].num * TXB_ELEMENT_SIZE; - for (i = start; i < end; i += 4) - writel(0x0, priv->mram_base + i); - + m_can_init_ram(priv); } static int m_can_plat_probe(struct platform_device *pdev) From 8a3f3f24a829c80d8d451e75e887912c3905dfd0 Mon Sep 17 00:00:00 2001 From: Quentin Schulz Date: Fri, 5 May 2017 15:50:31 +0200 Subject: [PATCH 2/4] can: m_can: make m_can_start and m_can_stop symmetric This moves clocks gating outside of the m_can_stop function as the m_can_start function does not (and cannot, at least in current implementation) ungate clocks. This way, both functions can now be used symmetrically. Signed-off-by: Quentin Schulz Signed-off-by: Marc Kleine-Budde --- drivers/net/can/m_can/m_can.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index 5da1bdb202a3..6115dede671e 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1324,9 +1324,6 @@ static void m_can_stop(struct net_device *dev) /* disable all interrupts */ m_can_disable_all_interrupts(priv); - clk_disable_unprepare(priv->hclk); - clk_disable_unprepare(priv->cclk); - /* set the state as STOPPED */ priv->can.state = CAN_STATE_STOPPED; } @@ -1338,6 +1335,8 @@ static int m_can_close(struct net_device *dev) netif_stop_queue(dev); napi_disable(&priv->napi); m_can_stop(dev); + clk_disable_unprepare(priv->hclk); + clk_disable_unprepare(priv->cclk); free_irq(dev->irq, dev); close_candev(dev); can_led_event(dev, CAN_LED_EVENT_STOP); From ef7b8aa8ca4acdd0541c622230de93bb3389ef41 Mon Sep 17 00:00:00 2001 From: Quentin Schulz Date: Fri, 5 May 2017 15:50:32 +0200 Subject: [PATCH 3/4] can: m_can: factorize clock gating and ungating This creates a function to ungate M_CAN clocks and another to gate the same clocks, then swaps all gating/ungating code with their respective function. Signed-off-by: Quentin Schulz Signed-off-by: Marc Kleine-Budde --- drivers/net/can/m_can/m_can.c | 45 ++++++++++++++++++++--------------- 1 file changed, 26 insertions(+), 19 deletions(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index 6115dede671e..653b304d7091 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -621,10 +621,8 @@ static int __m_can_get_berr_counter(const struct net_device *dev, return 0; } -static int m_can_get_berr_counter(const struct net_device *dev, - struct can_berr_counter *bec) +static int m_can_clk_start(struct m_can_priv *priv) { - struct m_can_priv *priv = netdev_priv(dev); int err; err = clk_prepare_enable(priv->hclk); @@ -632,15 +630,31 @@ static int m_can_get_berr_counter(const struct net_device *dev, return err; err = clk_prepare_enable(priv->cclk); - if (err) { + if (err) clk_disable_unprepare(priv->hclk); + + return err; +} + +static void m_can_clk_stop(struct m_can_priv *priv) +{ + clk_disable_unprepare(priv->cclk); + clk_disable_unprepare(priv->hclk); +} + +static int m_can_get_berr_counter(const struct net_device *dev, + struct can_berr_counter *bec) +{ + struct m_can_priv *priv = netdev_priv(dev); + int err; + + err = m_can_clk_start(priv); + if (err) return err; - } __m_can_get_berr_counter(dev, bec); - clk_disable_unprepare(priv->cclk); - clk_disable_unprepare(priv->hclk); + m_can_clk_stop(priv); return 0; } @@ -1276,19 +1290,15 @@ static int m_can_open(struct net_device *dev) struct m_can_priv *priv = netdev_priv(dev); int err; - err = clk_prepare_enable(priv->hclk); + err = m_can_clk_start(priv); if (err) return err; - err = clk_prepare_enable(priv->cclk); - if (err) - goto exit_disable_hclk; - /* open the can device */ err = open_candev(dev); if (err) { netdev_err(dev, "failed to open can device\n"); - goto exit_disable_cclk; + goto exit_disable_clks; } /* register interrupt handler */ @@ -1310,10 +1320,8 @@ static int m_can_open(struct net_device *dev) exit_irq_fail: close_candev(dev); -exit_disable_cclk: - clk_disable_unprepare(priv->cclk); -exit_disable_hclk: - clk_disable_unprepare(priv->hclk); +exit_disable_clks: + m_can_clk_stop(priv); return err; } @@ -1335,8 +1343,7 @@ static int m_can_close(struct net_device *dev) netif_stop_queue(dev); napi_disable(&priv->napi); m_can_stop(dev); - clk_disable_unprepare(priv->hclk); - clk_disable_unprepare(priv->cclk); + m_can_clk_stop(priv); free_irq(dev->irq, dev); close_candev(dev); can_led_event(dev, CAN_LED_EVENT_STOP); From d14ccea0e71a55ad02bf4e1cb378bbece282d5cf Mon Sep 17 00:00:00 2001 From: Quentin Schulz Date: Fri, 5 May 2017 15:50:33 +0200 Subject: [PATCH 4/4] can: m_can: add deep Suspend/Resume support This adds Power Management deep Suspend/Resume support for Bosch M_CAN chip. When entering deep sleep, the clocks are gated, the interrupts are disabled. When resuming from deep sleep, the chip needs to be reinitialized, the clocks ungated and the interrupts enabled. Signed-off-by: Quentin Schulz Signed-off-by: Marc Kleine-Budde --- drivers/net/can/m_can/m_can.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index 653b304d7091..f4947a74b65f 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1668,6 +1668,8 @@ static int m_can_plat_probe(struct platform_device *pdev) return ret; } +/* TODO: runtime PM with power down or sleep mode */ + static __maybe_unused int m_can_suspend(struct device *dev) { struct net_device *ndev = dev_get_drvdata(dev); @@ -1676,10 +1678,10 @@ static __maybe_unused int m_can_suspend(struct device *dev) if (netif_running(ndev)) { netif_stop_queue(ndev); netif_device_detach(ndev); + m_can_stop(ndev); + m_can_clk_stop(priv); } - /* TODO: enter low power */ - priv->can.state = CAN_STATE_SLEEPING; return 0; @@ -1690,11 +1692,18 @@ static __maybe_unused int m_can_resume(struct device *dev) struct net_device *ndev = dev_get_drvdata(dev); struct m_can_priv *priv = netdev_priv(ndev); - /* TODO: exit low power */ + m_can_init_ram(priv); priv->can.state = CAN_STATE_ERROR_ACTIVE; if (netif_running(ndev)) { + int ret; + + ret = m_can_clk_start(priv); + if (ret) + return ret; + + m_can_start(ndev); netif_device_attach(ndev); netif_start_queue(ndev); }