[ARM/tegra] nvrm spi: use lazy disable for spi busy hint

SPI driver normally enables / disables CPU and bus frequency boost
at the start / end of each SPI transaction.  Instead of turning off
frequency boost immediately at the end of each SPI transaction, use
a timeout period after which frequency boost hints will time out.
The timeout period is calculated based on the number of bytes in
the SPI transaction and the SPI clock rate.  The timeout insures that
frequency boost is still active in between multiple SPI transactions.
This has the side effect of increasing SPI data transfer rate for
multiple SPI transactions.

This was a cherry-pick from android-tegra-2.6.29
id: I088127ebb5ea07810dac824bfafd3f99ae6c96f2 and
applied to the android-tegra-2.6.32.

Change-Id: I765e892cb34a4fff8d8607cdf52cec065979c6e7
Reviewed-on: http://git-master/r/2338
Reviewed-by: Michael Hsu <mhsu@nvidia.com>
Tested-by: Michael Hsu <mhsu@nvidia.com>
Reviewed-by: Gary King <gking@nvidia.com>

1 files changed, 17 insertions, 14 deletions

diff --git a/arch/arm/mach-tegra/nvrm/io/ap15/rm_spi_slink.c b/arch/arm/mach-tegra/nvrm/io/ap15/rm_spi_slink.c
index c9220113262f..d2ed962c6b3f 100644
--- a/arch/arm/mach-tegra/nvrm/io/ap15/rm_spi_slink.c
+++ b/arch/arm/mach-tegra/nvrm/io/ap15/rm_spi_slink.c
@@ -799,7 +799,7 @@ RegisterSpiSlinkInterrupt(
             &hIntHandlers, hRmSpiSlink, &hRmSpiSlink->SpiInterruptHandle, NV_TRUE));
 }
 // Boosting the Emc/Ahb/Apb/Cpu frequency
-static void BoostFrequency(NvRmSpiHandle hRmSpiSlink, NvBool IsBoost, NvU32 TransactionSize)
+static void BoostFrequency(NvRmSpiHandle hRmSpiSlink, NvBool IsBoost, NvU32 TransactionSize, NvU32 ClockSpeedInKHz)
 {
     if (IsBoost)
     {
@@ -808,10 +808,18 @@ static void BoostFrequency(NvRmSpiHandle hRmSpiSlink, NvBool IsBoost, NvU32 Tran
             if (!((hRmSpiSlink->IsPmuInterface) &&
                    (hRmSpiSlink->PmuChipSelectId == hRmSpiSlink->CurrTransferChipSelId)))
             {
-                hRmSpiSlink->BusyHints[0].BoostKHz = 80000; // Emc
-                hRmSpiSlink->BusyHints[1].BoostKHz = 80000; // Ahb
-                hRmSpiSlink->BusyHints[2].BoostKHz = 80000; // Apb
-                hRmSpiSlink->BusyHints[3].BoostKHz = 240000; // Cpu
+                hRmSpiSlink->BusyHints[0].BoostKHz = 150000; // Emc
+                hRmSpiSlink->BusyHints[0].BoostDurationMs
+                    = 10 + ((4 * (TransactionSize * 8))) / ClockSpeedInKHz;
+                hRmSpiSlink->BusyHints[1].BoostKHz = 150000; // Ahb
+                hRmSpiSlink->BusyHints[1].BoostDurationMs
+                    = 10 + ((4 * (TransactionSize * 8))) / ClockSpeedInKHz;
+                hRmSpiSlink->BusyHints[2].BoostKHz = 150000; // Apb
+                hRmSpiSlink->BusyHints[2].BoostDurationMs
+                    = 10 + ((4 * (TransactionSize * 8))) / ClockSpeedInKHz;
+                hRmSpiSlink->BusyHints[3].BoostKHz = 600000; // Cpu
+                hRmSpiSlink->BusyHints[3].BoostDurationMs
+                    = 10 + ((4 * (TransactionSize * 8))) / ClockSpeedInKHz;
                 NvRmPowerBusyHintMulti(hRmSpiSlink->hDevice, hRmSpiSlink->RmPowerClientId,
                                        hRmSpiSlink->BusyHints, 4,
                                        NvRmDfsBusyHintSyncMode_Async);
@@ -894,7 +902,7 @@ static void DestroySpiSlinkChannelHandle(NvRmSpiHandle hRmSpiSlink)
 #if NV_OAL
 
     // Resetting the Emc/Ahb/Apb/Cpu frequency
-    BoostFrequency(hRmSpiSlink, NV_FALSE, 0);
+    BoostFrequency(hRmSpiSlink, NV_FALSE, 0, 0);
     (void)SetPowerControl(hRmSpiSlink, NV_FALSE);
 #endif
 
@@ -2463,7 +2471,7 @@ void NvRmSpiMultipleTransactions(
         TotalTransByte += pTrans->len;
     }
 
-    BoostFrequency(hRmSpi, NV_TRUE, TotalTransByte);
+    BoostFrequency(hRmSpi, NV_TRUE, TotalTransByte, ClockSpeedInKHz);
 
     hRmSpi->CurrTransInfo.PacketsPerWord = PacketsPerWord;
     if (SpiPinMap)
@@ -2594,7 +2602,6 @@ cleanup:
         hRmSpi->IsApbDmaAllocated = NV_FALSE;
     }
 
-    BoostFrequency(hRmSpi, NV_FALSE, 0);
     SetPowerControl(hRmSpi, NV_FALSE);
     NvOsMutexUnlock(hRmSpi->hChannelAccessMutex);
     NV_ASSERT(Error == NvSuccess);
@@ -2657,7 +2664,7 @@ void NvRmSpiTransaction(
     Error = SetPowerControl(hRmSpi, NV_TRUE);
     if (Error != NvSuccess)
         goto cleanup;
-    BoostFrequency(hRmSpi, NV_TRUE, BytesRequested);
+    BoostFrequency(hRmSpi, NV_TRUE, BytesRequested, ClockSpeedInKHz);
 
 #else
     hRmSpi->CurrTransferChipSelId = ChipSelectId;
@@ -2785,7 +2792,6 @@ cleanup:
     }
 
 #if !NV_OAL
-    BoostFrequency(hRmSpi, NV_FALSE, 0);
     SetPowerControl(hRmSpi, NV_FALSE);
     NvOsMutexUnlock(hRmSpi->hChannelAccessMutex);
 #endif
@@ -2875,7 +2881,7 @@ NvError NvRmSpiStartTransaction(
     // Enable Power/Clock.
     Error = SetPowerControl(hRmSpi, NV_TRUE);
     if (!Error)
-        BoostFrequency(hRmSpi, NV_TRUE, BytesRequested);
+        BoostFrequency(hRmSpi, NV_TRUE, BytesRequested, ClockSpeedInKHz);
 
     if (!Error)
         Error = SetChipSelectSignalLevel(hRmSpi, ChipSelectId, ClockSpeedInKHz,
@@ -2927,7 +2933,6 @@ cleanup:
     if (hRmSpi->IsIdleSignalTristate)
         NvRmPinMuxConfigSetTristate(hRmSpi->hDevice,hRmSpi->RmIoModuleId,
             hRmSpi->InstanceId, hRmSpi->SpiPinMap, NV_TRUE);
-    BoostFrequency(hRmSpi, NV_FALSE, 0);
     SetPowerControl(hRmSpi, NV_FALSE);
     NvOsMutexUnlock(hRmSpi->hChannelAccessMutex);
     return Error;
@@ -2960,8 +2965,6 @@ NvRmSpiGetTransactionData(
         NvRmPinMuxConfigSetTristate(hRmSpiSlink->hDevice,hRmSpiSlink->RmIoModuleId,
             hRmSpiSlink->InstanceId, hRmSpiSlink->SpiPinMap, NV_TRUE);
 
-    BoostFrequency(hRmSpiSlink, NV_FALSE, 0);
-
     // Disable Power/Clock.
     SetPowerControl(hRmSpiSlink, NV_FALSE);
     NvOsMutexUnlock(hRmSpiSlink->hChannelAccessMutex);