[POWERPC] Add common clock setting routine mpc52xx_psc_set_clkdiv()

PSC drivers should not access the CDM registers directly.  Instead provide
a common routine for setting the PSC clock parameters with the required
locking.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

4 files changed, 72 insertions, 12 deletions

diff --git a/arch/powerpc/platforms/52xx/efika.c b/arch/powerpc/platforms/52xx/efika.c
index a0da70c8b502..a2068faef6ea 100644
--- a/arch/powerpc/platforms/52xx/efika.c
+++ b/arch/powerpc/platforms/52xx/efika.c
@@ -180,6 +180,9 @@ static void __init efika_setup_arch(void)
 {
         rtas_initialize();
 
+        /* Map important registers from the internal memory map */
+        mpc52xx_map_common_devices();
+
         efika_pcisetup();
 
 #ifdef CONFIG_PM
diff --git a/arch/powerpc/platforms/52xx/lite5200.c b/arch/powerpc/platforms/52xx/lite5200.c
index fb35b285a146..956f459e175c 100644
--- a/arch/powerpc/platforms/52xx/lite5200.c
+++ b/arch/powerpc/platforms/52xx/lite5200.c
@@ -152,15 +152,15 @@ static void __init lite5200_setup_arch(void)
         if (ppc_md.progress)
                 ppc_md.progress("lite5200_setup_arch()", 0);
 
-        /* Fix things that firmware should have done. */
-        lite5200_fix_clock_config();
-        lite5200_fix_port_config();
+        /* Map important registers from the internal memory map */
+        mpc52xx_map_common_devices();
 
         /* Some mpc5200 & mpc5200b related configuration */
         mpc5200_setup_xlb_arbiter();
 
-        /* Map wdt for mpc52xx_restart() */
-        mpc52xx_map_wdt();
+        /* Fix things that firmware should have done. */
+        lite5200_fix_clock_config();
+        lite5200_fix_port_config();
 
 #ifdef CONFIG_PM
         mpc52xx_suspend.board_suspend_prepare = lite5200_suspend_prepare;
diff --git a/arch/powerpc/platforms/52xx/mpc5200_simple.c b/arch/powerpc/platforms/52xx/mpc5200_simple.c
index 754aa932f595..c48b82bc2aad 100644
--- a/arch/powerpc/platforms/52xx/mpc5200_simple.c
+++ b/arch/powerpc/platforms/52xx/mpc5200_simple.c
@@ -39,12 +39,12 @@ static void __init mpc5200_simple_setup_arch(void)
         if (ppc_md.progress)
                 ppc_md.progress("mpc5200_simple_setup_arch()", 0);
 
+        /* Map important registers from the internal memory map */
+        mpc52xx_map_common_devices();
+
         /* Some mpc5200 & mpc5200b related configuration */
         mpc5200_setup_xlb_arbiter();
 
-        /* Map wdt for mpc52xx_restart() */
-        mpc52xx_map_wdt();
-
         mpc52xx_setup_pci();
 }
 
diff --git a/arch/powerpc/platforms/52xx/mpc52xx_common.c b/arch/powerpc/platforms/52xx/mpc52xx_common.c
index 744eb3a34ec9..9aa4425d80b2 100644
--- a/arch/powerpc/platforms/52xx/mpc52xx_common.c
+++ b/arch/powerpc/platforms/52xx/mpc52xx_common.c
@@ -13,6 +13,7 @@
 #undef DEBUG
 
 #include <linux/kernel.h>
+#include <linux/spinlock.h>
 #include <linux/of_platform.h>
 #include <asm/io.h>
 #include <asm/prom.h>
@@ -41,7 +42,9 @@ static struct of_device_id mpc52xx_bus_ids[] __initdata = {
  * from interrupt context while node mapping (which calls ioremap())
  * cannot be used at such point.
  */
-static volatile struct mpc52xx_gpt *mpc52xx_wdt = NULL;
+static spinlock_t mpc52xx_lock = SPIN_LOCK_UNLOCKED;
+static struct mpc52xx_gpt __iomem *mpc52xx_wdt;
+static struct mpc52xx_cdm __iomem *mpc52xx_cdm;
 
 /**
  *      mpc52xx_find_ipb_freq - Find the IPB bus frequency for a device
@@ -120,18 +123,27 @@ mpc52xx_declare_of_platform_devices(void)
 }
 
 /*
- * match tables used by mpc52xx_map_wdt()
+ * match tables used by mpc52xx_map_common_devices()
  */
 static struct of_device_id mpc52xx_gpt_ids[] __initdata = {
         { .compatible = "fsl,mpc5200-gpt", },
         { .compatible = "mpc5200-gpt", }, /* old */
         {}
 };
+static struct of_device_id mpc52xx_cdm_ids[] __initdata = {
+        { .compatible = "fsl,mpc5200-cdm", },
+        { .compatible = "mpc5200-cdm", }, /* old */
+        {}
+};
 
+/**
+ * mpc52xx_map_common_devices: iomap devices required by common code
+ */
 void __init
-mpc52xx_map_wdt(void)
+mpc52xx_map_common_devices(void)
 {
         struct device_node *np;
+
         /* mpc52xx_wdt is mapped here and used in mpc52xx_restart,
          * possibly from a interrupt context. wdt is only implement
          * on a gpt0, so check has-wdt property before mapping.
@@ -141,11 +153,56 @@ mpc52xx_map_wdt(void)
                     of_get_property(np, "has-wdt", NULL)) {
                         mpc52xx_wdt = of_iomap(np, 0);
                         of_node_put(np);
-                        return;
+                        break;
                 }
         }
+
+        /* Clock Distribution Module, used by PSC clock setting function */
+        np = of_find_matching_node(NULL, mpc52xx_cdm_ids);
+        mpc52xx_cdm = of_iomap(np, 0);
+        of_node_put(np);
 }
 
+/**
+ * mpc52xx_set_psc_clkdiv: Set clock divider in the CDM for PSC ports
+ *
+ * @psc_id: id of psc port; must be 1,2,3 or 6
+ * @clkdiv: clock divider value to put into CDM PSC register.
+ */
+int mpc52xx_set_psc_clkdiv(int psc_id, int clkdiv)
+{
+        unsigned long flags;
+        u16 __iomem *reg;
+        u32 val;
+        u32 mask;
+        u32 mclken_div;
+
+        if (!mpc52xx_cdm)
+                return -ENODEV;
+
+        mclken_div = 0x8000 | (clkdiv & 0x1FF);
+        switch (psc_id) {
+        case 1: reg = &mpc52xx_cdm->mclken_div_psc1; mask = 0x20; break;
+        case 2: reg = &mpc52xx_cdm->mclken_div_psc2; mask = 0x40; break;
+        case 3: reg = &mpc52xx_cdm->mclken_div_psc3; mask = 0x80; break;
+        case 6: reg = &mpc52xx_cdm->mclken_div_psc6; mask = 0x10; break;
+        default:
+                return -ENODEV;
+        }
+
+        /* Set the rate and enable the clock */
+        spin_lock_irqsave(&mpc52xx_lock, flags);
+        out_be16(reg, mclken_div);
+        val = in_be32(&mpc52xx_cdm->clk_enables);
+        out_be32(&mpc52xx_cdm->clk_enables, val | mask);
+        spin_unlock_irqrestore(&mpc52xx_lock, flags);
+
+        return 0;
+}
+
+/**
+ * mpc52xx_restart: ppc_md->restart hook for mpc5200 using the watchdog timer
+ */
 void
 mpc52xx_restart(char *cmd)
 {