@@ -31,3 +31,40 @@ mpc5xxx_get_bus_frequency(struct device_node *node)
return p_bus_freq ? *p_bus_freq : 0;
}
EXPORT_SYMBOL(mpc5xxx_get_bus_frequency);
+
+/**
+ * mpc5xxx_get_get_mii_speed - Get the MII_SPEED value
+ * @node: device node
+ *
+ * Returns the MII_SPEED value for MPC512x and MPC52xx systems.
+ * The value gets computed such that the resulting MDC frequency
+ * is 2.5 MHz or lower.
+ */
+
+int
+mpc5xxx_get_mii_speed(struct of_device *ofdev)
+{
+ unsigned int clock, speed;
+
+ clock = mpc5xxx_get_bus_frequency(ofdev->node);
+
+ if (!clock) {
+ dev_err(&ofdev->dev, "could not determine IPS/IPB clock\n");
+ return -ENODEV;
+ }
+
+ /* scale for a MII clock <= 2.5 MHz */
+ speed = (clock + 2499999) / 2500000;
+
+ /* only 6 bits available for MII speed */
+ if (speed > 0x3F) {
+ speed = 0x3F;
+ dev_err(&ofdev->dev,
+ "MII clock (%d MHz) exceeds max (2.5 MHz)\n",
+ clock / speed);
+ }
+
+ /* Field is in bits 25:30 of MII_SPEED register */
+ return speed << 1;
+}
+EXPORT_SYMBOL(mpc5xxx_get_mii_speed);
@@ -36,6 +36,7 @@
#include <asm/pgtable.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
+#include <asm/mpc5xxx.h>
#include "fs_enet.h"
#include "fec.h"
@@ -152,13 +153,17 @@ static int __devinit fs_enet_mdio_probe(struct of_device *ofdev,
if (!fec->fecp)
goto out_fec;
- fec->mii_speed = ((ppc_proc_freq + 4999999) / 5000000) << 1;
+ i = mpc5xxx_get_mii_speed(ofdev);
+ if (i < 0)
+ goto out_unmap_regs;
+
+ fec->mii_speed = i;
setbits32(&fec->fecp->fec_r_cntrl, FEC_RCNTRL_MII_MODE);
setbits32(&fec->fecp->fec_ecntrl, FEC_ECNTRL_PINMUX |
FEC_ECNTRL_ETHER_EN);
out_be32(&fec->fecp->fec_ievent, FEC_ENET_MII);
- out_be32(&fec->fecp->fec_mii_speed, fec->mii_speed);
+ clrsetbits_be32(&fec->fecp->fec_mii_speed, 0x7E, fec->mii_speed);
new_bus->phy_mask = ~0;
new_bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
The MII speed calculation was incorrectly based on the CPU clock (ppc_proc_freq) instead of the bus clock; it worked only by chance and for some CPU clock frequencies. This patch makes it use the correct clock and adds some error handling. Signed-off-by: Wolfgang Denk <wd@denx.de> Cc: Grant Likely <grant.likely@secretlab.ca> Cc: Kumar Gala <galak@kernel.crashing.org> --- This is mostly a fix for an old bug - it's starnge that this went unnoticed so far. It worked only because the incorrectly computed value was truncated due to the fact that the MII_SPEED field in the rebister is only 6 bits wide - but, depending on the system clock frequency, non working systems (MII_SPEED set to zero or DIS_PREAMBLE set to one) might result as well. This patch is marked a RFC for the following reasons: 1) drivers/net/fs_enet/mii-fec.c now uses mpc5xxx_get_mii_speed() which makes it 5xxx specific. I don't really like this, but did not see a clean way to avoid it either. 2) We probably should also use mpc5xxx_get_mii_speed() in drivers/net/fec_mpc52xx.c and drivers/net/fec_mpc52xx_phy.c, which also contain code to calculate the MII speed. But then we should also add some error checking to the code there, and we should make sure that only the bits that belong to the MII_SPEED field get written when setting the MII speed. I'm not sure if such changes are considered necessary, and if, if they should be added to this patch or handled in a separate one. arch/powerpc/sysdev/mpc5xxx_clocks.c | 37 ++++++++++++++++++++++++++++++++++ drivers/net/fs_enet/mii-fec.c | 9 ++++++- 2 files changed, 44 insertions(+), 2 deletions(-)