This patch introduces VP force update method of voltage scaling
and enables it by default. The older method of vc bypass is now
configuratble through a menu config option. VP force update is the
hardware recommended method of voltage scaling.

Signed-off-by: Thara Gopinath <th...@ti.com>
---
 arch/arm/mach-omap2/voltage.c |  149 +++++++++++++++++++++++++++++++++++++++--
 arch/arm/mach-omap2/voltage.h |    1 +
 arch/arm/plat-omap/Kconfig    |   19 +++++
 3 files changed, 162 insertions(+), 7 deletions(-)

diff --git a/arch/arm/mach-omap2/voltage.c b/arch/arm/mach-omap2/voltage.c
index 49167c0..4f325af 100644
--- a/arch/arm/mach-omap2/voltage.c
+++ b/arch/arm/mach-omap2/voltage.c
@@ -29,7 +29,8 @@
 #include "prm-regbits-34xx.h"
 #include "voltage.h"
 
-#define VP_IDLE_TIMEOUT 200
+#define VP_IDLE_TIMEOUT        200
+#define VP_TRANXDONE_TIMEOUT   300
 
 /*
  * OMAP3 Voltage controller SR parameters. TODO: Pass this info as part of
@@ -70,6 +71,7 @@ struct vp_reg_info {
        u32 vp_vddmin;
        u32 vp_vddmax;
        u32 vp_timeout;
+       u32 vp_tranxdone_status;
 };
 static struct vp_reg_info *vp_reg;
 /*
@@ -299,6 +301,8 @@ static void __init vp_reg_configure(int vp_id)
                                        OMAP3430_VDDMIN_SHIFT);
                        vp_reg[vp_id].vp_vddmax = (OMAP3_VP1_VLIMITTO_VDDMAX <<
                                        OMAP3430_VDDMAX_SHIFT);
+                       vp_reg[vp_id].vp_tranxdone_status =
+                                       OMAP3430_VP1_TRANXDONE_ST;
                } else if (vp_id == VP2) {
                        /*
                         * OMAP3430 has error gain varying btw higher and
@@ -312,6 +316,8 @@ static void __init vp_reg_configure(int vp_id)
                                        OMAP3430_VDDMIN_SHIFT);
                        vp_reg[vp_id].vp_vddmax = (OMAP3_VP2_VLIMITTO_VDDMAX <<
                                        OMAP3430_VDDMAX_SHIFT);
+                       vp_reg[vp_id].vp_tranxdone_status =
+                                       OMAP3430_VP2_TRANXDONE_ST;
                } else {
                        pr_warning("Voltage processor%d does not exisit\
                                        in OMAP3 \n", vp_id);
@@ -346,6 +352,131 @@ static void __init vp_reg_configure(int vp_id)
        /* TODO Extend this for OMAP4 ?? Or need a separate file  */
 }
 
+#ifdef CONFIG_OMAP_VOLT_VPFORCEUPDATE
+/* VP force update method of voltage scaling */
+static int vp_forceupdate_scale_voltage(u32 vdd, u8 target_vsel,
+                               u8 current_vsel)
+{
+       u32 smps_steps = 0, smps_delay = 0;
+       u32 vpconfig;
+       int timeout = 0;
+       int vp_id = vdd - 1;
+
+       if (!((vdd == VDD1_OPP) || (vdd == VDD2_OPP))) {
+               pr_warning("Wrong vdd id passed to vp forceupdate\n");
+               return false;
+       }
+
+       smps_steps = abs(target_vsel - current_vsel);
+
+       /* OMAP3430 has errorgain varying btw higher and lower opp's */
+       if (cpu_is_omap34xx()) {
+               if (vdd == VDD1_OPP) {
+                       u32 vc_cmdval0;
+
+                       vc_cmdval0 = voltage_read_reg(vc_reg.vc_cmdval0_reg);
+                       vc_cmdval0 &= ~VC_CMD_ON_MASK;
+                       vc_cmdval0 |= (target_vsel << VC_CMD_ON_SHIFT);
+                       voltage_write_reg(vc_reg.vc_cmdval0_reg, vc_cmdval0);
+                       vp_reg[vp_id].vp_errorgain = (((get_vdd1_opp() > 2) ?
+                                       (OMAP3_VP_CONFIG_ERRORGAIN_HIGHOPP) :
+                                       (OMAP3_VP_CONFIG_ERRORGAIN_LOWOPP)) <<
+                                       OMAP3430_ERRORGAIN_SHIFT);
+               } else if (vdd == VDD2_OPP) {
+                       u32 vc_cmdval1;
+
+                       vc_cmdval1 = voltage_read_reg(vc_reg.vc_cmdval1_reg);
+                       vc_cmdval1 &= ~VC_CMD_ON_MASK;
+                       vc_cmdval1 |= (target_vsel << VC_CMD_ON_SHIFT);
+                       voltage_write_reg(vc_reg.vc_cmdval1_reg, vc_cmdval1);
+                       vp_reg[vp_id].vp_errorgain = (((get_vdd2_opp() > 2) ?
+                                       (OMAP3_VP_CONFIG_ERRORGAIN_HIGHOPP) :
+                                       (OMAP3_VP_CONFIG_ERRORGAIN_LOWOPP)) <<
+                                       OMAP3430_ERRORGAIN_SHIFT);
+               }
+       }
+
+       /* Clear all pending TransactionDone interrupt/status. Typical latency
+        * is <3us
+        */
+       while (timeout++ < VP_TRANXDONE_TIMEOUT) {
+               voltage_write_reg(PRM_IRQSTATUS_REG,
+                               vp_reg[vp_id].vp_tranxdone_status);
+               if (!(voltage_read_reg(PRM_IRQSTATUS_REG) &
+                               vp_reg[vp_id].vp_tranxdone_status))
+                               break;
+               udelay(1);
+       }
+
+       if (timeout >= VP_TRANXDONE_TIMEOUT) {
+               pr_warning("VP%d TRANXDONE timeout exceeded. Voltage change \
+                               aborted", vdd);
+               return false;
+       }
+
+       /* Configure for VP-Force Update */
+       vpconfig = voltage_read_reg(vp_reg[vp_id].vp_offs.vp_vpconfig_reg);
+       vpconfig &= ~(VP_CONFIG_INITVDD | VP_FORCEUPDATE |
+                       VP_INITVOLTAGE_MASK | VP_ERRORGAIN_MASK);
+       vpconfig |= ((target_vsel << VP_INITVOLTAGE_SHIFT) |
+                       vp_reg[vp_id].vp_errorgain);
+       voltage_write_reg(vp_reg[vp_id].vp_offs.vp_vpconfig_reg, vpconfig);
+
+       /* Trigger initVDD value copy to voltage processor */
+       vpconfig |= VP_CONFIG_INITVDD;
+       voltage_write_reg(vp_reg[vp_id].vp_offs.vp_vpconfig_reg, vpconfig);
+
+       /* Force update of voltage */
+       vpconfig |= VP_FORCEUPDATE;
+       voltage_write_reg(vp_reg[vp_id].vp_offs.vp_vpconfig_reg, vpconfig);
+
+       timeout = 0;
+       /* Wait for TransactionDone. Typical latency is <200us.
+        * Depends on SMPSWAITTIMEMIN/MAX and voltage change
+        */
+       while ((timeout++ < VP_TRANXDONE_TIMEOUT) &&
+                       (!(voltage_read_reg(PRM_IRQSTATUS_REG) &
+                       vp_reg[vp_id].vp_tranxdone_status)))
+               udelay(1);
+
+       if (timeout >= VP_TRANXDONE_TIMEOUT)
+               pr_warning("VP%d TRANXDONE timeout exceeded. TRANXDONE never \
+                       got set after the voltage update.Serious error!!!!\n",
+                       vdd);
+
+       /* Wait for voltage to settle with SW wait-loop */
+       smps_delay = ((smps_steps * 125) / 40) + 2;
+       udelay(smps_delay);
+
+       /* Disable TransactionDone interrupt , clear all status, clear
+        * control registers
+        */
+       timeout = 0;
+       while (timeout++ < VP_TRANXDONE_TIMEOUT) {
+               voltage_write_reg(PRM_IRQSTATUS_REG,
+                               vp_reg[vp_id].vp_tranxdone_status);
+               if (!(voltage_read_reg(PRM_IRQSTATUS_REG) &
+                               vp_reg[vp_id].vp_tranxdone_status))
+                               break;
+               udelay(1);
+       }
+       if (timeout >= VP_TRANXDONE_TIMEOUT)
+               pr_warning("VP%d TRANXDONE timeout exceeded while trying to \
+                       clear the TRANXDONE status\n", vdd);
+
+       vpconfig = voltage_read_reg(vp_reg[vp_id].vp_offs.vp_vpconfig_reg);
+       /* Clear initVDD copy trigger bit */
+       vpconfig &= ~VP_CONFIG_INITVDD;
+       voltage_write_reg(vp_reg[vp_id].vp_offs.vp_vpconfig_reg, vpconfig);
+       /* Clear force bit */
+       vpconfig &= ~VP_FORCEUPDATE;
+       voltage_write_reg(vp_reg[vp_id].vp_offs.vp_vpconfig_reg, vpconfig);
+
+       return true;
+}
+#endif
+
+#ifdef CONFIG_OMAP_VOLT_VCBYPASS
 /**
  * vc_bypass_scale_voltage - VC bypass method of voltage scaling
  */
@@ -437,7 +568,7 @@ static int vc_bypass_scale_voltage(u32 vdd, u8 target_vsel, 
u8 current_vsel)
        udelay(smps_delay);
        return true;
 }
-
+#endif
 
 static void __init init_voltageprocessors(void)
 {
@@ -474,13 +605,16 @@ void omap_voltageprocessor_enable(int vp_id)
        if (voltage_read_reg(vp_reg[vp_id - 1].vp_offs.vp_vpconfig_reg) &
                                VP_CONFIG_VPENABLE)
                return;
+
+#ifdef CONFIG_OMAP_VOLT_VCBYPASS
        /*
         * This latching is required only if VC bypass method is used for
         * voltage scaling during dvfs.
         */
        vp_latch_vsel(vp_id - 1);
-       vpconfig = voltage_read_reg(vp_reg[vp_id - 1].vp_offs.vp_vpconfig_reg);
+#endif
        /* Enable VP */
+       vpconfig = voltage_read_reg(vp_reg[vp_id - 1].vp_offs.vp_vpconfig_reg);
        voltage_write_reg(vp_reg[vp_id - 1].vp_offs.vp_vpconfig_reg,
                                vpconfig | VP_CONFIG_VPENABLE);
 }
@@ -529,11 +663,12 @@ void omap_voltageprocessor_disable(int vp_id)
  * for a particular voltage domain during dvfs or any other situation.
  */
 int omap_voltage_scale(int vdd, u8 target_vsel, u8 current_vsel)
-{      /*
-        * TODO add VP force update method of voltage scaling
-        * and choose btw the two
-        */
+{
+#ifdef CONFIG_OMAP_VOLT_VCBYPASS
        return vc_bypass_scale_voltage(vdd, target_vsel, current_vsel);
+#elif CONFIG_OMAP_VOLT_VPFORCEUPDATE
+       return vp_forceupdate_scale_voltage(vdd, target_vsel, current_vsel);
+#endif
 }
 
 /**
diff --git a/arch/arm/mach-omap2/voltage.h b/arch/arm/mach-omap2/voltage.h
index c3203c9..615bde6 100644
--- a/arch/arm/mach-omap2/voltage.h
+++ b/arch/arm/mach-omap2/voltage.h
@@ -17,6 +17,7 @@
 extern int get_vdd1_opp(void);
 extern int get_vdd2_opp(void);
 
+#define PRM_IRQSTATUS_REG      OMAP3430_PRM_IRQSTATUS_MPU
 /* Generic VP definitions. Need to be redefined for OMAP4 */
 #define VP_CONFIG_TIMEOUTEN    OMAP3430_TIMEOUTEN
 #define VP_CONFIG_INITVDD      OMAP3430_INITVDD
diff --git a/arch/arm/plat-omap/Kconfig b/arch/arm/plat-omap/Kconfig
index 9d286e6..1a611a9 100644
--- a/arch/arm/plat-omap/Kconfig
+++ b/arch/arm/plat-omap/Kconfig
@@ -92,6 +92,25 @@ config OMAP_SMARTREFLEX_TESTING
 
          WARNING: Enabling this option may cause your device to hang!
 
+choice
+       prompt "Choose Voltage Scale method"
+       depends on ARCH_OMAP3 && PM
+       default OMAP_VOLT_VPFORCEUPDATE
+
+config OMAP_VOLT_VPFORCEUPDATE
+       bool "Voltage scaling via VP force update method"
+       help
+        Say Y if you want to enable VP force update method
+        of voltage scaling. This is the h/w recomended way
+        of voltage scaling in OMAP3.
+
+config OMAP_VOLT_VCBYPASS
+       bool "Voltage Scale via Voltage controller in bypass"
+       help
+        Say Y if you want to enable VC Bypass method of voltage scaling.
+        Not the default recommended method.
+endchoice
+
 config OMAP_RESET_CLOCKS
        bool "Reset unused clocks during boot"
        depends on ARCH_OMAP
-- 
1.7.0.rc1.33.g07cf0f

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