can: mscan-mpc5xxx: add support for the MPC512x processor

The main differences compared to the MSCAN on the MPC5200 are:

- More flexibility in choosing the CAN source clock and frequency:

  Three different clock sources can be selected: "ip", "ref" or "sys".
  For the latter two, a clock divider can be defined as well. If the
  clock source is not specified by the device tree, we first try to
  find an optimal CAN source clock based on the system clock. If that
  is not possible, the reference clock will be used.

- The behavior of bus-off recovery is configurable:

  To comply with the usual handling of Socket-CAN bus-off recovery,
  "recovery on request" is selected (instead of automatic recovery).

Note that only MPC5121 Rev. 2 and later is supported.

Signed-off-by: Wolfgang Grandegger <wg@denx.de>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 204 insertions, 42 deletions

diff --git a/drivers/net/can/mscan/mpc5xxx_can.c b/drivers/net/can/mscan/mpc5xxx_can.c
index 1de6f6349b1..f73487f723b 100644
--- a/drivers/net/can/mscan/mpc5xxx_can.c
+++ b/drivers/net/can/mscan/mpc5xxx_can.c
@@ -29,6 +29,7 @@
 #include <linux/can/dev.h>
 #include <linux/of_platform.h>
 #include <sysdev/fsl_soc.h>
+#include <linux/clk.h>
 #include <linux/io.h>
 #include <asm/mpc52xx.h>
 
@@ -36,22 +37,21 @@
 
 #define DRV_NAME "mpc5xxx_can"
 
-static struct of_device_id mpc52xx_cdm_ids[] __devinitdata = {
+struct mpc5xxx_can_data {
+	unsigned int type;
+	u32 (*get_clock)(struct of_device *ofdev, const char *clock_name,
+			 int *mscan_clksrc);
+};
+
+#ifdef CONFIG_PPC_MPC5200
+static struct of_device_id __devinitdata mpc52xx_cdm_ids[] = {
 	{ .compatible = "fsl,mpc5200-cdm", },
 	{}
 };
 
-/*
- * Get frequency of the MSCAN clock source
- *
- * Either the oscillator clock (SYS_XTAL_IN) or the IP bus clock (IP_CLK)
- * can be selected. According to the MPC5200 user's manual, the oscillator
- * clock is the better choice as it has less jitter but due to a hardware
- * bug, it can not be selected for the old MPC5200 Rev. A chips.
- */
-
-static unsigned int  __devinit mpc52xx_can_clock_freq(struct of_device *of,
-						      int clock_src)
+static u32 __devinit mpc52xx_can_get_clock(struct of_device *ofdev,
+					   const char *clock_name,
+					   int *mscan_clksrc)
 {
 	unsigned int pvr;
 	struct mpc52xx_cdm  __iomem *cdm;
@@ -61,11 +61,24 @@ static unsigned int  __devinit mpc52xx_can_clock_freq(struct of_device *of,
 
 	pvr = mfspr(SPRN_PVR);
 
-	freq = mpc5xxx_get_bus_frequency(of->node);
+	/*
+	 * Either the oscillator clock (SYS_XTAL_IN) or the IP bus clock
+	 * (IP_CLK) can be selected as MSCAN clock source. According to
+	 * the MPC5200 user's manual, the oscillator clock is the better
+	 * choice as it has less jitter. For this reason, it is selected
+	 * by default. Unfortunately, it can not be selected for the old
+	 * MPC5200 Rev. A chips due to a hardware bug (check errata).
+	 */
+	if (clock_name && strcmp(clock_name, "ip") == 0)
+		*mscan_clksrc = MSCAN_CLKSRC_BUS;
+	else
+		*mscan_clksrc = MSCAN_CLKSRC_XTAL;
+
+	freq = mpc5xxx_get_bus_frequency(ofdev->node);
 	if (!freq)
 		return 0;
 
-	if (clock_src == MSCAN_CLKSRC_BUS || pvr == 0x80822011)
+	if (*mscan_clksrc == MSCAN_CLKSRC_BUS || pvr == 0x80822011)
 		return freq;
 
 	/* Determine SYS_XTAL_IN frequency from the clock domain settings */
@@ -75,7 +88,6 @@ static unsigned int  __devinit mpc52xx_can_clock_freq(struct of_device *of,
 		return 0;
 	}
 	cdm = of_iomap(np_cdm, 0);
-	of_node_put(np_cdm);
 
 	if (in_8(&cdm->ipb_clk_sel) & 0x1)
 		freq *= 2;
@@ -84,26 +96,174 @@ static unsigned int  __devinit mpc52xx_can_clock_freq(struct of_device *of,
 	freq *= (val & (1 << 5)) ? 8 : 4;
 	freq /= (val & (1 << 6)) ? 12 : 16;
 
+	of_node_put(np_cdm);
 	iounmap(cdm);
 
 	return freq;
 }
+#else /* !CONFIG_PPC_MPC5200 */
+static u32 __devinit mpc52xx_can_get_clock(struct of_device *ofdev,
+					   const char *clock_name,
+					   int *mscan_clksrc)
+{
+	return 0;
+}
+#endif /* CONFIG_PPC_MPC5200 */
+
+#ifdef CONFIG_PPC_MPC512x
+struct mpc512x_clockctl {
+	u32 spmr;		/* System PLL Mode Reg */
+	u32 sccr[2];		/* System Clk Ctrl Reg 1 & 2 */
+	u32 scfr1;		/* System Clk Freq Reg 1 */
+	u32 scfr2;		/* System Clk Freq Reg 2 */
+	u32 reserved;
+	u32 bcr;		/* Bread Crumb Reg */
+	u32 pccr[12];		/* PSC Clk Ctrl Reg 0-11 */
+	u32 spccr;		/* SPDIF Clk Ctrl Reg */
+	u32 cccr;		/* CFM Clk Ctrl Reg */
+	u32 dccr;		/* DIU Clk Cnfg Reg */
+	u32 mccr[4];		/* MSCAN Clk Ctrl Reg 1-3 */
+};
+
+static struct of_device_id __devinitdata mpc512x_clock_ids[] = {
+	{ .compatible = "fsl,mpc5121-clock", },
+	{}
+};
+
+static u32 __devinit mpc512x_can_get_clock(struct of_device *ofdev,
+					   const char *clock_name,
+					   int *mscan_clksrc)
+{
+	struct mpc512x_clockctl __iomem *clockctl;
+	struct device_node *np_clock;
+	struct clk *sys_clk, *ref_clk;
+	int plen, clockidx, clocksrc = -1;
+	u32 sys_freq, val, clockdiv = 1, freq = 0;
+	const u32 *pval;
+
+	np_clock = of_find_matching_node(NULL, mpc512x_clock_ids);
+	if (!np_clock) {
+		dev_err(&ofdev->dev, "couldn't find clock node\n");
+		return -ENODEV;
+	}
+	clockctl = of_iomap(np_clock, 0);
+	if (!clockctl) {
+		dev_err(&ofdev->dev, "couldn't map clock registers\n");
+		return 0;
+	}
+
+	/* Determine the MSCAN device index from the physical address */
+	pval = of_get_property(ofdev->node, "reg", &plen);
+	BUG_ON(!pval || plen < sizeof(*pval));
+	clockidx = (*pval & 0x80) ? 1 : 0;
+	if (*pval & 0x2000)
+		clockidx += 2;
+
+	/*
+	 * Clock source and divider selection: 3 different clock sources
+	 * can be selected: "ip", "ref" or "sys". For the latter two, a
+	 * clock divider can be defined as well. If the clock source is
+	 * not specified by the device tree, we first try to find an
+	 * optimal CAN source clock based on the system clock. If that
+	 * is not posslible, the reference clock will be used.
+	 */
+	if (clock_name && !strcmp(clock_name, "ip")) {
+		*mscan_clksrc = MSCAN_CLKSRC_IPS;
+		freq = mpc5xxx_get_bus_frequency(ofdev->node);
+	} else {
+		*mscan_clksrc = MSCAN_CLKSRC_BUS;
+
+		pval = of_get_property(ofdev->node,
+				       "fsl,mscan-clock-divider", &plen);
+		if (pval && plen == sizeof(*pval))
+			clockdiv = *pval;
+		if (!clockdiv)
+			clockdiv = 1;
+
+		if (!clock_name || !strcmp(clock_name, "sys")) {
+			sys_clk = clk_get(&ofdev->dev, "sys_clk");
+			if (!sys_clk) {
+				dev_err(&ofdev->dev, "couldn't get sys_clk\n");
+				goto exit_unmap;
+			}
+			/* Get and round up/down sys clock rate */
+			sys_freq = 1000000 *
+				((clk_get_rate(sys_clk) + 499999) / 1000000);
+
+			if (!clock_name) {
+				/* A multiple of 16 MHz would be optimal */
+				if ((sys_freq % 16000000) == 0) {
+					clocksrc = 0;
+					clockdiv = sys_freq / 16000000;
+					freq = sys_freq / clockdiv;
+				}
+			} else {
+				clocksrc = 0;
+				freq = sys_freq / clockdiv;
+			}
+		}
+
+		if (clocksrc < 0) {
+			ref_clk = clk_get(&ofdev->dev, "ref_clk");
+			if (!ref_clk) {
+				dev_err(&ofdev->dev, "couldn't get ref_clk\n");
+				goto exit_unmap;
+			}
+			clocksrc = 1;
+			freq = clk_get_rate(ref_clk) / clockdiv;
+		}
+	}
+
+	/* Disable clock */
+	out_be32(&clockctl->mccr[clockidx], 0x0);
+	if (clocksrc >= 0) {
+		/* Set source and divider */
+		val = (clocksrc << 14) | ((clockdiv - 1) << 17);
+		out_be32(&clockctl->mccr[clockidx], val);
+		/* Enable clock */
+		out_be32(&clockctl->mccr[clockidx], val | 0x10000);
+	}
+
+	/* Enable MSCAN clock domain */
+	val = in_be32(&clockctl->sccr[1]);
+	if (!(val & (1 << 25)))
+		out_be32(&clockctl->sccr[1], val | (1 << 25));
+
+	dev_dbg(&ofdev->dev, "using '%s' with frequency divider %d\n",
+		*mscan_clksrc == MSCAN_CLKSRC_IPS ? "ips_clk" :
+		clocksrc == 1 ? "ref_clk" : "sys_clk", clockdiv);
+
+exit_unmap:
+	of_node_put(np_clock);
+	iounmap(clockctl);
+
+	return freq;
+}
+#else /* !CONFIG_PPC_MPC512x */
+static u32 __devinit mpc512x_can_get_clock(struct of_device *ofdev,
+					   const char *clock_name,
+					   int *mscan_clksrc)
+{
+	return 0;
+}
+#endif /* CONFIG_PPC_MPC512x */
 
 static int __devinit mpc5xxx_can_probe(struct of_device *ofdev,
 				       const struct of_device_id *id)
 {
+	struct mpc5xxx_can_data *data = (struct mpc5xxx_can_data *)id->data;
 	struct device_node *np = ofdev->node;
 	struct net_device *dev;
 	struct mscan_priv *priv;
 	void __iomem *base;
-	const char *clk_src;
-	int err, irq, clock_src;
+	const char *clock_name = NULL;
+	int irq, mscan_clksrc = 0;
+	int err = -ENOMEM;
 
-	base = of_iomap(ofdev->node, 0);
+	base = of_iomap(np, 0);
 	if (!base) {
 		dev_err(&ofdev->dev, "couldn't ioremap\n");
-		err = -ENOMEM;
-		goto exit_release_mem;
+		return err;
 	}
 
 	irq = irq_of_parse_and_map(np, 0);
@@ -114,37 +274,27 @@ static int __devinit mpc5xxx_can_probe(struct of_device *ofdev,
 	}
 
 	dev = alloc_mscandev();
-	if (!dev) {
-		err = -ENOMEM;
+	if (!dev)
 		goto exit_dispose_irq;
-	}
 
 	priv = netdev_priv(dev);
 	priv->reg_base = base;
 	dev->irq = irq;
 
-	/*
-	 * Either the oscillator clock (SYS_XTAL_IN) or the IP bus clock
-	 * (IP_CLK) can be selected as MSCAN clock source. According to
-	 * the MPC5200 user's manual, the oscillator clock is the better
-	 * choice as it has less jitter. For this reason, it is selected
-	 * by default.
-	 */
-	clk_src = of_get_property(np, "fsl,mscan-clock-source", NULL);
-	if (clk_src && strcmp(clk_src, "ip") == 0)
-		clock_src = MSCAN_CLKSRC_BUS;
-	else
-		clock_src = MSCAN_CLKSRC_XTAL;
-	priv->can.clock.freq = mpc52xx_can_clock_freq(ofdev, clock_src);
+	clock_name = of_get_property(np, "fsl,mscan-clock-source", NULL);
+
+	BUG_ON(!data);
+	priv->type = data->type;
+	priv->can.clock.freq = data->get_clock(ofdev, clock_name,
+					       &mscan_clksrc);
 	if (!priv->can.clock.freq) {
-		dev_err(&ofdev->dev, "couldn't get MSCAN clock frequency\n");
-		err = -ENODEV;
+		dev_err(&ofdev->dev, "couldn't get MSCAN clock properties\n");
 		goto exit_free_mscan;
 	}
 
 	SET_NETDEV_DEV(dev, &ofdev->dev);
 
-	err = register_mscandev(dev, clock_src);
+	err = register_mscandev(dev, mscan_clksrc);
 	if (err) {
 		dev_err(&ofdev->dev, "registering %s failed (err=%d)\n",
 			DRV_NAME, err);
@@ -164,7 +314,7 @@ exit_dispose_irq:
 	irq_dispose_mapping(irq);
 exit_unmap_mem:
 	iounmap(base);
-exit_release_mem:
+
 	return err;
 }
 
@@ -225,8 +375,20 @@ static int mpc5xxx_can_resume(struct of_device *ofdev)
 }
 #endif
 
+static struct mpc5xxx_can_data __devinitdata mpc5200_can_data = {
+	.type = MSCAN_TYPE_MPC5200,
+	.get_clock = mpc52xx_can_get_clock,
+};
+
+static struct mpc5xxx_can_data __devinitdata mpc5121_can_data = {
+	.type = MSCAN_TYPE_MPC5121,
+	.get_clock = mpc512x_can_get_clock,
+};
+
 static struct of_device_id __devinitdata mpc5xxx_can_table[] = {
-	{.compatible = "fsl,mpc5200-mscan"},
+	{ .compatible = "fsl,mpc5200-mscan", .data = &mpc5200_can_data, },
+	/* Note that only MPC5121 Rev. 2 (and later) is supported */
+	{ .compatible = "fsl,mpc5121-mscan", .data = &mpc5121_can_data, },
 	{},
 };
 
@@ -255,5 +417,5 @@ static void __exit mpc5xxx_can_exit(void)
 module_exit(mpc5xxx_can_exit);
 
 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
-MODULE_DESCRIPTION("Freescale MPC5200 CAN driver");
+MODULE_DESCRIPTION("Freescale MPC5xxx CAN driver");
 MODULE_LICENSE("GPL v2");