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Message-ID: <CAKT61h-CK6egUGG=eKj5wHJ1GTkXFaqQpu2dLpJnBJF_vGfEpw@mail.gmail.com>
Date: Wed, 23 Dec 2015 08:40:23 +0800
From: Wan ZongShun <mcuos.com@...il.com>
To: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: Wan Zongshun <vincent.wan@....com>,
Ulf Hansson <ulf.hansson@...aro.org>,
"linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
Borislav Petkov <bp@...e.de>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Huang Rui <ray.huang@....com>
Subject: Re: [PATCH 1/3] mmc: sdhci-pci: Add AMD HS200 mode tuning function
2015-12-22 17:52 GMT+08:00 Andy Shevchenko <andy.shevchenko@...il.com>:
> On Tue, Dec 22, 2015 at 6:40 PM, Wan Zongshun <vincent.wan@....com> wrote:
>> From: Wan Zongshun <Vincent.Wan@....com>
>>
>> This patch is to add software tuning functions for AMD hs200
>> mode.
>>
>> Signed-off-by: Wan Zongshun <Vincent.Wan@....com>
>> ---
>> drivers/mmc/host/sdhci-pci-core.c | 146 ++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 146 insertions(+)
>>
>> diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
>> index 08f4a9f..01c5723 100644
>> --- a/drivers/mmc/host/sdhci-pci-core.c
>> +++ b/drivers/mmc/host/sdhci-pci-core.c
>> @@ -729,6 +729,152 @@ enum amd_chipset_gen {
>> AMD_CHIPSET_UNKNOWN,
>> };
>>
>> +struct tuning_descriptor {
>> + unsigned char tune_around;
>> + bool this_tune_ok;
>> + bool last_tune_ok;
>> + bool valid_front_end;
>> + unsigned char valid_front;
>> + unsigned char valid_window_max;
>> + unsigned char tune_low_max;
>> + unsigned char tune_low;
>> + unsigned char valid_window;
>> + unsigned char tune_result;
>> +};
>> +
>> +#define AMD_EMMC_TUNE_REG 0xb8
>> +static struct tuning_descriptor tdescriptor;
>
> Global variable?!
Okay, will change it to local.
>
>> +
>> +static int tuning_reset(struct sdhci_host *host)
>
> Better prefixes?
Do you mean I should not name this function to tuning reset?
>
>> +{
>> + unsigned int val;
>> + unsigned long flags;
>> +
>> + spin_lock_irqsave(&host->lock, flags);
>> +
>> + val = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>> + val |= SDHCI_CTRL_PRESET_VAL_ENABLE | SDHCI_CTRL_EXEC_TUNING;
>> + sdhci_writew(host, val, SDHCI_HOST_CONTROL2);
>> +
>> + val = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>> + val &= ~SDHCI_CTRL_EXEC_TUNING;
>> + sdhci_writew(host, val, SDHCI_HOST_CONTROL2);
>> +
>> + spin_unlock_irqrestore(&host->lock, flags);
>> +
>> + return 0;
>> +}
>> +
>> +static int config_tuning_phase(struct sdhci_host *host, unsigned char phase)
>> +{
>> + struct sdhci_pci_slot *slot = sdhci_priv(host);
>> + struct pci_dev *pdev = slot->chip->pdev;
>> + unsigned int val;
>> + unsigned long flags;
>> +
>> + spin_lock_irqsave(&host->lock, flags);
>> +
>> + pci_read_config_dword(pdev, AMD_EMMC_TUNE_REG, &val);
>> + val &= ~0xf;
>> + val |= (0x10800 | phase);
>
> Magic.
Okay, I will make 0x10800 to be see more clearly, will define each bit
Macro for it.
>
>> + pci_write_config_dword(pdev, AMD_EMMC_TUNE_REG, val);
>> +
>> + spin_unlock_irqrestore(&host->lock, flags);
>> +
>> + return 0;
>> +}
>> +
>> +static int find_good_phase(struct sdhci_host *host)
>> +{
>> + struct tuning_descriptor *td = &tdescriptor;
>> + struct sdhci_pci_slot *slot = sdhci_priv(host);
>> + struct pci_dev *pdev = slot->chip->pdev;
>> + unsigned int val;
>> + unsigned long flags;
>> +
>> + spin_lock_irqsave(&host->lock, flags);
>> +
>> + if (td->this_tune_ok == false)
>> + td->valid_front_end = 1;
>> +
>> + if (td->valid_front_end)
>> + td->valid_front = td->valid_front;
>> + else if (td->this_tune_ok)
>> + td->valid_front = td->valid_front + 1;
>> +
>> + if ((!td->this_tune_ok && td->last_tune_ok) ||
>> + (td->tune_around == 11)) {
>
> Magic.
>
>> + if (td->valid_window > td->valid_window_max) {
>> + td->valid_window_max = td->valid_window;
>> + td->tune_low_max = td->tune_low;
>> + }
>> + }
>> +
>> + if (td->this_tune_ok) {
>> + if (!td->last_tune_ok)
>> + td->tune_low = td->tune_around;
>> + td->valid_window = td->valid_window + 1;
>> + } else {
>> + if (td->last_tune_ok)
>> + td->valid_window = 0x0;
>> + }
>> +
>> + td->last_tune_ok = td->this_tune_ok;
>> +
>> + if (td->tune_around == 11) {
>> + if ((td->valid_front + td->valid_window) >
>> + td->valid_window_max) {
>> + if (td->valid_front > td->valid_window)
>> + td->tune_result =
>> + ((td->valid_front - td->valid_window) >> 1);
>> + else
>> + td->tune_result = td->tune_low +
>> + ((td->valid_window + td->valid_front) >> 1);
>> + } else {
>> + td->tune_result =
>> + td->tune_low_max + (td->valid_window_max >> 1);
>> + }
>> +
>> + if (td->tune_result > 0x0b)
>> + td->tune_result = 0x0b;
>> +
>> + pci_read_config_dword(pdev, AMD_EMMC_TUNE_REG, &val);
>> + val &= ~0xf;
>> + val |= (0x10800 | td->tune_result);
>
> Magic.
>
>> + pci_write_config_dword(pdev, AMD_EMMC_TUNE_REG, val);
>> + }
>> +
>> + spin_unlock_irqrestore(&host->lock, flags);
>> +
>> + return 0;
>> +}
>> +
>> +static int amd_execute_tuning(struct sdhci_host *host, u32 opcode)
>> +{
>> + struct tuning_descriptor *td = &tdescriptor;
>> +
>> + tuning_reset(host);
>> +
>> + for (td->tune_around = 0; td->tune_around < 12; td->tune_around++) {
>
> Magic.
>
> Why loop is done with non-local variable?
It will be changed at next version.
thanks!
>
>> +
>> + config_tuning_phase(host, td->tune_around);
>> +
>> + if (mmc_send_tuning(host->mmc, opcode, NULL)) {
>> + td->this_tune_ok = false;
>> + host->mmc->need_retune = 0;
>> + mdelay(4);
>> + } else {
>> + td->this_tune_ok = true;
>> + }
>> +
>> + find_good_phase(host);
>> + }
>> +
>> + host->mmc->retune_period = 0;
>> +
>> + return 0;
>> +}
>> +
>> static int amd_probe(struct sdhci_pci_chip *chip)
>> {
>> struct pci_dev *smbus_dev;
>
> No users for such code. I don't think it makes sense to push it separately.
Since I am not sure the patch 2/3 is ok to every body, so it just is my try.
If we can make decision for patch2/3, I can integrate them into one
patch per your suggestion.
Thanks Andy.
>
> --
> With Best Regards,
> Andy Shevchenko
--
---
Vincent Wan(Zongshun)
www.mcuos.com
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