Re: [PATCH V2 8/9] PCI: tegra: Broadcast PME_turn_Off message before link goes to L2

[Manikanta Maddireddy <mmaddireddy@nvidia.com>]

On 29-Nov-17 10:21 PM, Bjorn Helgaas wrote:
> On Sun, Nov 26, 2017 at 01:02:12AM +0530, Manikanta Maddireddy wrote:
>> Per PCIe r3.0, sec 5.3.3.2.1, PCIe root port shoould broadcast PME_turn_Off
>> message before PCIe link goes to L2. PME_turn_Off broadcast mechanism is
>> implemented in AFI module. Each Tegra PCIe root port has its own
>> PME_turn_Off and PME_TO_Ack bitmap in AFI_PME register, program this
>> register to broadcast PME_turn_Off message.
> 
> s/PME_turn_Off/PME_Turn_Off/ above to match spec.
> 
> I thought PME_TO_Ack was also mis-capitalized, but it's not.  Guess
> that "TO" stands for "Turn Off".
> 
>> Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
>> ---
>> V2:
>> * no change in this patch
>>
>>  drivers/pci/host/pci-tegra.c | 76 ++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 76 insertions(+)
>>
>> diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
>> index bbc2807bcd4a..b380958a3deb 100644
>> --- a/drivers/pci/host/pci-tegra.c
>> +++ b/drivers/pci/host/pci-tegra.c
>> @@ -155,6 +155,8 @@
>>  #define  AFI_INTR_EN_FPCI_TIMEOUT	(1 << 7)
>>  #define  AFI_INTR_EN_PRSNT_SENSE	(1 << 8)
>>  
>> +#define AFI_PCIE_PME		0xf0
>> +
>>  #define AFI_PCIE_CONFIG					0x0f8
>>  #define  AFI_PCIE_CONFIG_PCIE_DISABLE(x)		(1 << ((x) + 1))
>>  #define  AFI_PCIE_CONFIG_PCIE_DISABLE_ALL		0xe
>> @@ -315,6 +317,7 @@
>>  #define PADS_REFCLK_CFG_DRVI_SHIFT		12 /* 15:12 */
>>  
>>  #define LINK_RETRAIN_TIMEOUT 100000
>> +#define PME_ACK_TIMEOUT 10000
>>  
>>  struct tegra_msi {
>>  	struct msi_controller chip;
>> @@ -1503,6 +1506,76 @@ static int tegra_pcie_put_resources(struct tegra_pcie *pcie)
>>  	return 0;
>>  }
>>  
>> +static inline u32 get_pme_turnoff_bitmap(struct tegra_pcie_port *port)
>> +{
>> +	struct device *dev = port->pcie->dev;
>> +	struct device_node *np = dev->of_node;
>> +	int ret = 0;
> 
> Unnecessary initialization.  In fact, the variable is unnecessary; you
> can just return the value directly as soon as you know it.
>
I can get rid of this function with Mikko's suggestion to use soc data
 
>> +
>> +	switch (port->index) {
>> +	case 0:
>> +		ret = 0;
>> +	case 1:
>> +		ret = 8;
>> +	case 2:
>> +		if (of_device_is_compatible(np, "nvidia,tegra30-pcie"))
>> +			ret = 16;
>> +		else
>> +			ret = 12;
>> +	}
>> +	return ret;
>> +}
>> +
>> +static inline u32 get_pme_ack_bitmap(struct tegra_pcie_port *port)
>> +{
>> +	struct device *dev = port->pcie->dev;
>> +	struct device_node *np = dev->of_node;
>> +	int ret = 0;
> 
> Similar.
>
Similar
 
>> +
>> +	switch (port->index) {
>> +	case 0:
>> +		ret = 5;
>> +	case 1:
>> +		ret = 10;
>> +	case 2:
>> +		if (of_device_is_compatible(np, "nvidia,tegra30-pcie"))
>> +			ret = 18;
>> +		else
>> +			ret = 14;
>> +	}
>> +	return ret;
>> +}
>> +
>> +static void tegra_pcie_pme_turnoff(struct tegra_pcie_port *port)
>> +{
>> +	struct tegra_pcie *pcie = port->pcie;
>> +	ktime_t deadline;
>> +	unsigned int data;
>> +
>> +	data = afi_readl(pcie, AFI_PCIE_PME);
>> +	data |= (0x1 << get_pme_turnoff_bitmap(port));
>> +	afi_writel(pcie, data, AFI_PCIE_PME);
>> +
>> +	deadline = ktime_add_us(ktime_get(), PME_ACK_TIMEOUT);
>> +	do {
>> +		data = afi_readl(pcie, AFI_PCIE_PME);
>> +		data &= (0x1 << get_pme_ack_bitmap(port));
>> +		udelay(1);
>> +		if (ktime_after(ktime_get(), deadline))
>> +			break;
>> +	} while (!data);
>> +
>> +	if (data)
>> +		dev_err(pcie->dev, "PME Ack is not receieved on port: %d\n",
> 
> s/receieved/received/
> 
>> +			port->index);
>> +
>> +	usleep_range(10000, 11000);
>> +
>> +	data = afi_readl(pcie, AFI_PCIE_PME);
>> +	data &= ~(0x1 << get_pme_turnoff_bitmap(port));
>> +	afi_writel(pcie, data, AFI_PCIE_PME);
>> +}
>> +
>>  static int tegra_msi_alloc(struct tegra_msi *chip)
>>  {
>>  	int msi;
>> @@ -2828,6 +2901,7 @@ static int tegra_pcie_remove(struct platform_device *pdev)
>>  {
>>  	struct tegra_pcie *pcie = platform_get_drvdata(pdev);
>>  	struct pci_host_bridge *host = pci_host_bridge_from_priv(pcie);
>> +	struct tegra_pcie_port *port, *tmp;
>>  
>>  	if (IS_ENABLED(CONFIG_DEBUG_FS))
>>  		tegra_pcie_debugfs_exit(pcie);
>> @@ -2835,6 +2909,8 @@ static int tegra_pcie_remove(struct platform_device *pdev)
>>  	pci_remove_root_bus(host->bus);
>>  	if (IS_ENABLED(CONFIG_PCI_MSI))
>>  		tegra_pcie_disable_msi(pcie);
>> +	list_for_each_entry_safe(port, tmp, &pcie->ports, list)
>> +		tegra_pcie_pme_turnoff(port);
>>  	tegra_pcie_disable_ports(pcie);
>>  	tegra_pcie_free_resources(pcie);
>>  	tegra_pcie_disable_controller(pcie);
>> -- 
>> 2.1.4
>>