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Commit 5e0eaa7d authored by Kenji Kaneshige's avatar Kenji Kaneshige Committed by Jesse Barnes
Browse files

PCI ASPM: cleanup calc_Lx_latency 



Cleanup for calc_L0S_latency() and calc_L1_latency().

  - Separate exit latency and acceptable latency calculation.
  - Some minor cleanups.

Acked-by: default avatarShaohua Li <shaohua.li@intel.com>
Signed-off-by: default avatarKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent 7ab70991

drivers/pci/pcie/aspm.c

+34 −39
Original line number Diff line number Diff line
@@ -257,38 +257,36 @@ static void pcie_aspm_configure_common_clock(struct pcie_link_state *link) 
	pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, parent_reg);

}



/*

 * calc_L0S_latency: Convert L0s latency encoding to ns

 */

static unsigned int calc_L0S_latency(unsigned int latency_encoding, int ac)

/* Convert L0s latency encoding to ns */

static u32 calc_l0s_latency(u32 encoding)

{

	unsigned int ns = 64;

	if (encoding == 0x7)

		return (5 * 1000);	/* > 4us */

	return (64 << encoding);

}



	if (latency_encoding == 0x7) {

		if (ac)

			ns = -1U;

		else

			ns = 5*1000; /* > 4us */

	} else

		ns *= (1 << latency_encoding);

	return ns;

/* Convert L0s acceptable latency encoding to ns */

static u32 calc_l0s_acceptable(u32 encoding)

{

	if (encoding == 0x7)

		return -1U;

	return (64 << encoding);

}



/*

 * calc_L1_latency: Convert L1 latency encoding to ns

 */

static unsigned int calc_L1_latency(unsigned int latency_encoding, int ac)

/* Convert L1 latency encoding to ns */

static u32 calc_l1_latency(u32 encoding)

{

	unsigned int ns = 1000;

	if (encoding == 0x7)

		return (65 * 1000);	/* > 64us */

	return (1000 << encoding);

}



	if (latency_encoding == 0x7) {

		if (ac)

			ns = -1U;

		else

			ns = 65*1000; /* > 64us */

	} else

		ns *= (1 << latency_encoding);

	return ns;

/* Convert L1 acceptable latency encoding to ns */

static u32 calc_l1_acceptable(u32 encoding)

{

	if (encoding == 0x7)

		return -1U;

	return (1000 << encoding);

}



static void pcie_aspm_get_cap_device(struct pci_dev *pdev, u32 *state,
@@ -296,7 +294,7 @@ static void pcie_aspm_get_cap_device(struct pci_dev *pdev, u32 *state, 
{

	int pos;

	u16 reg16;

	u32 reg32, latency;

	u32 reg32, encoding;



	*l0s = *l1 = *enabled = 0;

	pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
@@ -308,11 +306,11 @@ static void pcie_aspm_get_cap_device(struct pci_dev *pdev, u32 *state, 
	if (*state == 0)

		return;



	latency = (reg32 & PCI_EXP_LNKCAP_L0SEL) >> 12;

	*l0s = calc_L0S_latency(latency, 0);

	encoding = (reg32 & PCI_EXP_LNKCAP_L0SEL) >> 12;

	*l0s = calc_l0s_latency(encoding);

	if (*state & PCIE_LINK_STATE_L1) {

		latency = (reg32 & PCI_EXP_LNKCAP_L1EL) >> 15;

		*l1 = calc_L1_latency(latency, 0);

		encoding = (reg32 & PCI_EXP_LNKCAP_L1EL) >> 15;

		*l1 = calc_l1_latency(encoding);

	}

	pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &reg16);

	*enabled = reg16 & (PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1);
@@ -358,8 +356,7 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) 
	/* ENDPOINT states*/

	list_for_each_entry(child, &linkbus->devices, bus_list) {

		int pos;

		u32 reg32;

		unsigned int latency;

		u32 reg32, encoding;

		struct aspm_latency *acceptable =

			&link->acceptable[PCI_FUNC(child->devfn)];
@@ -369,13 +366,11 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) 


		pos = pci_find_capability(child, PCI_CAP_ID_EXP);

		pci_read_config_dword(child, pos + PCI_EXP_DEVCAP, &reg32);

		latency = (reg32 & PCI_EXP_DEVCAP_L0S) >> 6;

		latency = calc_L0S_latency(latency, 1);

		acceptable->l0s = latency;

		encoding = (reg32 & PCI_EXP_DEVCAP_L0S) >> 6;

		acceptable->l0s = calc_l0s_acceptable(encoding);

		if (link->aspm_support & PCIE_LINK_STATE_L1) {

			latency = (reg32 & PCI_EXP_DEVCAP_L1) >> 9;

			latency = calc_L1_latency(latency, 1);

			acceptable->l1 = latency;

			encoding = (reg32 & PCI_EXP_DEVCAP_L1) >> 9;

			acceptable->l1 = calc_l1_acceptable(encoding);

		}

	}

}