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PCI: rcar: Try increasing PCIe link speed to 5 GT/s at boot

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The PCIe link speed is initially set to 2.5 GT/s.  Try to increase the link
speed to 5 GT/s.

Based on original patch by Grigory Kletsko
<grigory.kletsko@cogentembedded.com>.

[bhelgaas: remove "Trying speed up" message, remove unused SPCHG]
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
This commit is contained in:
Sergei Shtylyov 2016-09-22 23:20:18 +03:00 committed by Bjorn Helgaas
parent f7bc63802d
commit b3327f7fae
1 changed files with 66 additions and 0 deletions
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66
drivers/pci/host/pcie-rcar.c
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@ -84,8 +84,18 @@
#define IDSETR1 0x011004
#define TLCTLR 0x011048
#define MACSR 0x011054
#define SPCHGFIN (1 << 4)
#define SPCHGFAIL (1 << 6)
#define SPCHGSUC (1 << 7)
#define LINK_SPEED (0xf << 16)
#define LINK_SPEED_2_5GTS (1 << 16)
#define LINK_SPEED_5_0GTS (2 << 16)
#define MACCTLR 0x011058
#define SPEED_CHANGE (1 << 24)
#define SCRAMBLE_DISABLE (1 << 27)
#define MACS2R 0x011078
#define MACCGSPSETR 0x011084
#define SPCNGRSN (1 << 31)
/* R-Car H1 PHY */
#define H1_PCIEPHYADRR 0x04000c
@ -385,11 +395,67 @@ static int rcar_pcie_setup(struct list_head *resource, struct rcar_pcie *pci)
return 1;
}
static void rcar_pcie_force_speedup(struct rcar_pcie *pcie)
{
unsigned int timeout = 1000;
u32 macsr;
if ((rcar_pci_read_reg(pcie, MACS2R) & LINK_SPEED) != LINK_SPEED_5_0GTS)
return;
if (rcar_pci_read_reg(pcie, MACCTLR) & SPEED_CHANGE) {
dev_err(pcie->dev, "Speed change already in progress\n");
return;
}
macsr = rcar_pci_read_reg(pcie, MACSR);
if ((macsr & LINK_SPEED) == LINK_SPEED_5_0GTS)
goto done;
/* Set target link speed to 5.0 GT/s */
rcar_rmw32(pcie, EXPCAP(12), PCI_EXP_LNKSTA_CLS,
PCI_EXP_LNKSTA_CLS_5_0GB);
/* Set speed change reason as intentional factor */
rcar_rmw32(pcie, MACCGSPSETR, SPCNGRSN, 0);
/* Clear SPCHGFIN, SPCHGSUC, and SPCHGFAIL */
if (macsr & (SPCHGFIN | SPCHGSUC | SPCHGFAIL))
rcar_pci_write_reg(pcie, macsr, MACSR);
/* Start link speed change */
rcar_rmw32(pcie, MACCTLR, SPEED_CHANGE, SPEED_CHANGE);
while (timeout--) {
macsr = rcar_pci_read_reg(pcie, MACSR);
if (macsr & SPCHGFIN) {
/* Clear the interrupt bits */
rcar_pci_write_reg(pcie, macsr, MACSR);
if (macsr & SPCHGFAIL)
dev_err(pcie->dev, "Speed change failed\n");
goto done;
}
msleep(1);
};
dev_err(pcie->dev, "Speed change timed out\n");
done:
dev_info(pcie->dev, "Current link speed is %s GT/s\n",
(macsr & LINK_SPEED) == LINK_SPEED_5_0GTS ? "5" : "2.5");
}
static int rcar_pcie_enable(struct rcar_pcie *pcie)
{
struct pci_bus *bus, *child;
LIST_HEAD(res);
/* Try setting 5 GT/s link speed */
rcar_pcie_force_speedup(pcie);
rcar_pcie_setup(&res, pcie);
pci_add_flags(PCI_REASSIGN_ALL_RSRC | PCI_REASSIGN_ALL_BUS);