[PATCH] bcm43xx: fix pctl slowclock limit calculation

This fixes coverity bug:
http://marc.theaimsgroup.com/?l=linux-netdev&m=114417628413880&w=2

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 77 insertions, 47 deletions

diff --git a/drivers/net/wireless/bcm43xx/bcm43xx_power.c b/drivers/net/wireless/bcm43xx/bcm43xx_power.c
index 3c92b62807c5..6569da3a7a39 100644
--- a/drivers/net/wireless/bcm43xx/bcm43xx_power.c
+++ b/drivers/net/wireless/bcm43xx/bcm43xx_power.c
@@ -35,77 +35,101 @@
 #include "bcm43xx_main.h"
 
 
+/* Get the Slow Clock Source */
+static int bcm43xx_pctl_get_slowclksrc(struct bcm43xx_private *bcm)
+{
+        u32 tmp;
+        int err;
+
+        assert(bcm->current_core == &bcm->core_chipcommon);
+        if (bcm->current_core->rev < 6) {
+                if (bcm->bustype == BCM43xx_BUSTYPE_PCMCIA ||
+                    bcm->bustype == BCM43xx_BUSTYPE_SB)
+                        return BCM43xx_PCTL_CLKSRC_XTALOS;
+                if (bcm->bustype == BCM43xx_BUSTYPE_PCI) {
+                        err = bcm43xx_pci_read_config32(bcm, BCM43xx_PCTL_OUT, &tmp);
+                        assert(!err);
+                        if (tmp & 0x10)
+                                return BCM43xx_PCTL_CLKSRC_PCI;
+                        return BCM43xx_PCTL_CLKSRC_XTALOS;
+                }
+        }
+        if (bcm->current_core->rev < 10) {
+                tmp = bcm43xx_read32(bcm, BCM43xx_CHIPCOMMON_SLOWCLKCTL);
+                tmp &= 0x7;
+                if (tmp == 0)
+                        return BCM43xx_PCTL_CLKSRC_LOPWROS;
+                if (tmp == 1)
+                        return BCM43xx_PCTL_CLKSRC_XTALOS;
+                if (tmp == 2)
+                        return BCM43xx_PCTL_CLKSRC_PCI;
+        }
+
+        return BCM43xx_PCTL_CLKSRC_XTALOS;
+}
+
 /* Get max/min slowclock frequency
  * as described in http://bcm-specs.sipsolutions.net/PowerControl
  */
 static int bcm43xx_pctl_clockfreqlimit(struct bcm43xx_private *bcm,
                                        int get_max)
 {
-        int limit = 0;
+        int limit;
+        int clocksrc;
         int divisor;
-        int selection;
-        int err;
         u32 tmp;
-        struct bcm43xx_coreinfo *old_core;
 
-        if (!(bcm->chipcommon_capabilities & BCM43xx_CAPABILITIES_PCTL))
-                goto out;
-        old_core = bcm->current_core;
-        err = bcm43xx_switch_core(bcm, &bcm->core_chipcommon);
-        if (err)
-                goto out;
+        assert(bcm->chipcommon_capabilities & BCM43xx_CAPABILITIES_PCTL);
+        assert(bcm->current_core == &bcm->core_chipcommon);
 
+        clocksrc = bcm43xx_pctl_get_slowclksrc(bcm);
         if (bcm->current_core->rev < 6) {
-                if ((bcm->bustype == BCM43xx_BUSTYPE_PCMCIA) ||
-                        (bcm->bustype == BCM43xx_BUSTYPE_SB)) {
-                        selection = 1;
+                switch (clocksrc) {
+                case BCM43xx_PCTL_CLKSRC_PCI:
+                        divisor = 64;
+                        break;
+                case BCM43xx_PCTL_CLKSRC_XTALOS:
                         divisor = 32;
-                } else {
-                        err = bcm43xx_pci_read_config32(bcm, BCM43xx_PCTL_OUT, &tmp);
-                        if (err) {
-                                printk(KERN_ERR PFX "clockfreqlimit pcicfg read failure\n");
-                                goto out_switchback;
-                        }
-                        if (tmp & 0x10) {
-                                /* PCI */
-                                selection = 2;
-                                divisor = 64;
-                        } else {
-                                /* XTAL */
-                                selection = 1;
-                                divisor = 32;
-                        }
+                        break;
+                default:
+                        assert(0);
+                        divisor = 1;
                 }
         } else if (bcm->current_core->rev < 10) {
-                selection = (tmp & 0x07);
-                if (selection) {
+                switch (clocksrc) {
+                case BCM43xx_PCTL_CLKSRC_LOPWROS:
+                        divisor = 1;
+                        break;
+                case BCM43xx_PCTL_CLKSRC_XTALOS:
+                case BCM43xx_PCTL_CLKSRC_PCI:
                         tmp = bcm43xx_read32(bcm, BCM43xx_CHIPCOMMON_SLOWCLKCTL);
-                        divisor = 4 * (1 + ((tmp & 0xFFFF0000) >> 16));
-                } else
+                        divisor = ((tmp & 0xFFFF0000) >> 16) + 1;
+                        divisor *= 4;
+                        break;
+                default:
+                        assert(0);
                         divisor = 1;
+                }
         } else {
                 tmp = bcm43xx_read32(bcm, BCM43xx_CHIPCOMMON_SYSCLKCTL);
-                divisor = 4 * (1 + ((tmp & 0xFFFF0000) >> 16));
-                selection = 1;
+                divisor = ((tmp & 0xFFFF0000) >> 16) + 1;
+                divisor *= 4;
         }
-        
-        switch (selection) {
-        case 0:
-                /* LPO */
+
+        switch (clocksrc) {
+        case BCM43xx_PCTL_CLKSRC_LOPWROS:
                 if (get_max)
                         limit = 43000;
                 else
                         limit = 25000;
                 break;
-        case 1:
-                /* XTAL */
+        case BCM43xx_PCTL_CLKSRC_XTALOS:
                 if (get_max)
                         limit = 20200000;
                 else
                         limit = 19800000;
                 break;
-        case 2:
-                /* PCI */
+        case BCM43xx_PCTL_CLKSRC_PCI:
                 if (get_max)
                         limit = 34000000;
                 else
@@ -113,17 +137,14 @@ static int bcm43xx_pctl_clockfreqlimit(struct bcm43xx_private *bcm,
                 break;
         default:
                 assert(0);
+                limit = 0;
         }
         limit /= divisor;
 
-out_switchback:
-        err = bcm43xx_switch_core(bcm, old_core);
-        assert(err == 0);
-
-out:
         return limit;
 }
 
+
 /* init power control
  * as described in http://bcm-specs.sipsolutions.net/PowerControl
  */
diff --git a/drivers/net/wireless/bcm43xx/bcm43xx_power.h b/drivers/net/wireless/bcm43xx/bcm43xx_power.h
index 5f63640810bd..c966ab3a5a8c 100644
--- a/drivers/net/wireless/bcm43xx/bcm43xx_power.h
+++ b/drivers/net/wireless/bcm43xx/bcm43xx_power.h
@@ -33,6 +33,15 @@
 
 #include <linux/types.h>
 
+/* Clock sources */
+enum {
+        /* PCI clock */
+        BCM43xx_PCTL_CLKSRC_PCI,
+        /* Crystal slow clock oscillator */
+        BCM43xx_PCTL_CLKSRC_XTALOS,
+        /* Low power oscillator */
+        BCM43xx_PCTL_CLKSRC_LOPWROS,
+};
 
 struct bcm43xx_private;