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SubjectRe: [RFC PATCH 6/8] misc: emif: add interrupt and temperature handling
On Thursday 16 February 2012 04:11 PM, Santosh Shilimkar wrote:
> On Saturday 04 February 2012 05:46 PM, Aneesh V wrote:
>> Add an ISR for EMIF that:
>> 1. reports details of access errors
>> 2. takes action on thermal events
>>
>> On thermal events SDRAM timing parameters are
>> adjusted to ensure safe operation
>>
>> Also clear all interrupts on shut-down. Pending IRQs
>> may casue problems during warm-reset.
>>
> Add some more details like MR4, EMIF polling frequency etc
> for better understanding.

Will do.



>
>> Signed-off-by: Aneesh V<aneesh@ti.com>
>> ---
>> drivers/misc/emif.c | 209 ++++++++++++++++++++++++++++++++++++++++++++++++++-
>> 1 files changed, 207 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/misc/emif.c b/drivers/misc/emif.c
>> index 36ba6f4..5c2b0ae 100644
>> --- a/drivers/misc/emif.c
>> +++ b/drivers/misc/emif.c
>> @@ -500,6 +500,45 @@ static u32 get_pwr_mgmt_ctrl(u32 freq, struct emif_data *emif, u32 ip_rev)
>> }
>>
>> /*
>> + * Get the temperature level of the EMIF instance:
>> + * Reads the MR4 register of attached SDRAM parts to find out the temperature
>> + * level. If there are two parts attached(one on each CS), then the temperature
>> + * level for the EMIF instance is the higher of the two temperatures.
>> + */
>> +static void get_temperature_level(struct emif_data *emif)
>> +{
>> + u32 temp, temperature_level;
>> + unsigned long irqs;
>> + void __iomem *base;
>> +
>> + base = emif->base;
>> +
>> + /* Read mode register 4 */
>> + writel(DDR_MR4, base + EMIF_LPDDR2_MODE_REG_CONFIG);
>> + temperature_level = readl(base + EMIF_LPDDR2_MODE_REG_DATA);
>> + temperature_level = (temperature_level& MR4_SDRAM_REF_RATE_MASK)>>
>> + MR4_SDRAM_REF_RATE_SHIFT;
>> +
>> + if (emif->plat_data->device_info->cs1_used) {
>> + writel(DDR_MR4 | CS_MASK, base + EMIF_LPDDR2_MODE_REG_CONFIG);
>> + temp = readl(base + EMIF_LPDDR2_MODE_REG_DATA);
>> + temp = (temp& MR4_SDRAM_REF_RATE_MASK)
>> + >> MR4_SDRAM_REF_RATE_SHIFT;
>> + temperature_level = max(temp, temperature_level);
>> + }
>> +
>> + spin_lock_irqsave(&emif->lock, irqs);
> Add a line here.

Will do.

>> + /* treat everything less than nominal(3) in MR4 as nominal */
>> + if (unlikely(temperature_level< SDRAM_TEMP_NOMINAL))
>> + temperature_level = SDRAM_TEMP_NOMINAL;
>> +
>> + /* if we get reserved value in MR4 persist with the existing value */
>> + if (likely(temperature_level != SDRAM_TEMP_RESERVED_4))
>> + emif->temperature_level = temperature_level;
>> + spin_unlock_irqrestore(&emif->lock, irqs);
>> +}
>> +
>
> rest of the patch looks fine to me

Thanks,
Aneesh


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