This patch adds driver support for Tegra234 cpufreq.
Tegra234 has per core MMIO registers instead of system registers for
cpu frequency requests and to read the counters for re-constructing
the cpu frequency. Also, MPIDR affinity info in Tegra234 is different
from Tegra194.
Added ops hooks and soc data for Tegra234. This will help to easily
add variants of Tegra234 and future SoC's which use similar logic to
{get|set} the cpu frequency.
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Adding SoC data and ops to support multiple SoC's in same driver.
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
The return value from tegra_bpmp_transfer indicates the success or
failure of the IPC transaction with BPMP. If the transaction
succeeded, we also need to check the actual command's result code.
Add code to do this.
While at it, explicitly handle missing CPU clusters, which can
occur on floorswept chips. This worked before as well, but
possibly only by accident.
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
During cpufreq driver's registration, if the ->init() callback for all
the CPUs fail then there is not much point in keeping the driver around
as it will only account for more of unnecessary noise, for example
cpufreq core will try to suspend/resume the driver which never got
registered properly.
The removal of such a driver is avoided if the driver carries the
CPUFREQ_STICKY flag. This was added way back [1] in 2004 and perhaps no
one should ever need it now. A lot of drivers do set this flag, probably
because they just copied it from other drivers.
This was added earlier for some platforms [2] because their cpufreq
drivers were getting registered before the CPUs were registered with
subsys framework. And hence they used to fail.
The same isn't true anymore though. The current code flow in the kernel
is:
start_kernel()
-> kernel_init()
-> kernel_init_freeable()
-> do_basic_setup()
-> driver_init()
-> cpu_dev_init()
-> subsys_system_register() //For CPUs
-> do_initcalls()
-> cpufreq_register_driver()
Clearly, the CPUs will always get registered with subsys framework
before any cpufreq driver can get probed. Remove the flag and update the
relevant drivers.
Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/include/linux/cpufreq.h?id=7cc9f0d9a1ab04cedc60d64fd8dcf7df224a3b4d # [1]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/arch/arm/mach-sa1100/cpu-sa1100.c?id=f59d3bbe35f6268d729f51be82af8325d62f20f5 # [2]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The function tegra194_get_speed_common() uses hardware timers to
calculate the current CPUFREQ and so rename this function to be
tegra194_calculate_speed() to reflect what it does.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
The Tegra194 CPUFREQ driver sets the CPUFREQ_NEED_INITIAL_FREQ_CHECK
flag which means that the CPUFREQ framework will call the 'get' callback
on boot to determine the current frequency of the CPUs. Therefore, it is
not necessary for the Tegra194 CPUFREQ driver to internally call the
tegra194_get_speed_common() during initialisation to query the current
frequency as well. Fix this by removing the call to the
tegra194_get_speed_common() during initialisation and simplify the code.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Frequency returned by 'cpuinfo_cur_freq' using counters is not fixed
and keeps changing slightly. This change returns a consistent value
from freq_table. If the reconstructed frequency has acceptable delta
from the last written value, then return the frequency corresponding
to the last written ndiv value from freq_table. Otherwise, print a
warning and return the reconstructed freq.
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Commit eaecca9e77 ("arm64: Fix __cpu_logical_map undefined issue")
fixes the issue with building tegra194 cpufreq driver as module. But
the fix might cause problem while supporting physical CPU hotplug[1].
This patch fixes the original problem by avoiding use of cpu_logical_map().
Instead calling read_cpuid_mpidr() to get MPIDR on target CPU.
[1] https://lore.kernel.org/linux-arm-kernel/20200724131059.GB6521@bogus/
Fixes: df320f8935 ("cpufreq: Add Tegra194 cpufreq driver")
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject & changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add support for CPU frequency scaling on Tegra194. The frequency
of each core can be adjusted by writing a clock divisor value to
a MSR on the core. The range of valid divisors is queried from
the BPMP.
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
