Hi,
On Tue, Dec 12, 2017 at 02:31:28PM +0200, Ilia Lin wrote:
> The driver provides kernel level API for other drivers
> to access the MSM8996 L2 cache registers.
> Separating the L2 access code from the PMU driver and
> making it public to allow other drivers use it.
> The accesses must be separated with a single spinlock,
> maintained in this driver.
> -static void set_l2_indirect_reg(u64 reg, u64 val)
> -{
> - unsigned long flags;
> -
> - raw_spin_lock_irqsave(&l2_access_lock, flags);
> - write_sysreg_s(reg, L2CPUSRSELR_EL1);
> - isb();
> - write_sysreg_s(val, L2CPUSRDR_EL1);
> - isb();
> - raw_spin_unlock_irqrestore(&l2_access_lock, flags);
> -}
> +/**
> + * set_l2_indirect_reg: write value to an L2 register
> + * @reg: Address of L2 register.
> + * @value: Value to be written to register.
> + *
> + * Use architecturally required barriers for ordering between system register
> + * accesses, and system registers with respect to device memory
> + */
> +void set_l2_indirect_reg(u64 reg, u64 val)
> +{
> + unsigned long flags;
> + mb();
We didn't need this for the PMU driver, so it's unfortuante that it now
has to pay the cost.
Can we please factor this mb() into the callers that need it?
> + raw_spin_lock_irqsave(&l2_access_lock, flags);
> + write_sysreg_s(reg, L2CPUSRSELR_EL1);
> + isb();
> + write_sysreg_s(val, L2CPUSRDR_EL1);
> + isb();
> + raw_spin_unlock_irqrestore(&l2_access_lock, flags);
> +}
> +EXPORT_SYMBOL(set_l2_indirect_reg);
[...]
> +#ifdef CONFIG_ARCH_QCOM
> +void set_l2_indirect_reg(u64 reg_addr, u64 val);
> +u64 get_l2_indirect_reg(u64 reg_addr);
> +#else
> +static inline void set_l2_indirect_reg(u32 reg_addr, u32 val) {}
> +static inline u32 get_l2_indirect_reg(u32 reg_addr)
> +{
> + return 0;
> +}
> +#endif
> +#endif
Are there any drivers that will bne built for !CONFIG_ARCH_QCOM that
reference this?
It might be better to not have the stub versions, so that we get a
build-error if they are erroneously used.
Thannks,
Mark.
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