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Merge branch 'FEC-MDIO-speedups'
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Andrew Lunn says:

====================
FEC MDIO speedups

This patchset gives a number of speedups for MDIO with the FEC.
Replacing interrupt driven with polled IO brings a big speedup due to
the overheads of interrupts compared to the short time interval.
Clocking the bus faster, when the MDIO targets supports it, can double
the transfer rate. And suppressing the preamble, if devices support
it, makes each transaction faster.

By default the MDIO clock remains 2.5MHz and preables are used. But
these can now be controlled from the device tree. Since these are
generic properties applicable to more than just FEC, these have been
added to the generic MDIO binding documentation.

v2:
readl_poll_timeout()
Add patches to set bus frequency and preamble disable

v3:
Add Reviewed tags
uS->us
readl_poll_timeout_atomic()
Extend DT binding documentation
====================

Acked-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller committed Apr 20, 2020
2 parents 9d3679f + 3c01eb6 commit 749d22e
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1 change: 1 addition & 0 deletions Documentation/devicetree/bindings/net/fsl-fec.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -82,6 +82,7 @@ ethernet@83fec000 {
phy-supply = <&reg_fec_supply>;
phy-handle = <&ethphy>;
mdio {
clock-frequency = <5000000>;
ethphy: ethernet-phy@6 {
compatible = "ethernet-phy-ieee802.3-c22";
reg = <6>;
Expand Down
12 changes: 12 additions & 0 deletions Documentation/devicetree/bindings/net/mdio.yaml
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,18 @@ properties:
and must therefore be appropriately determined based on all PHY
requirements (maximum value of all per-PHY RESET pulse widths).

clock-frequency:
description:
Desired MDIO bus clock frequency in Hz. Values greater than IEEE 802.3
defined 2.5MHz should only be used when all devices on the bus support
the given clock speed.

suppress-preamble:
description:
The 32 bit preamble should be suppressed. In order for this to
work, all devices on the bus must support suppressed preamble.
type: boolean

patternProperties:
"^ethernet-phy@[0-9a-f]+$":
type: object
Expand Down
4 changes: 1 addition & 3 deletions drivers/net/ethernet/freescale/fec.h
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Original file line number Diff line number Diff line change
Expand Up @@ -376,8 +376,7 @@ struct bufdesc_ex {
#define FEC_ENET_TS_AVAIL ((uint)0x00010000)
#define FEC_ENET_TS_TIMER ((uint)0x00008000)

#define FEC_DEFAULT_IMASK (FEC_ENET_TXF | FEC_ENET_RXF | FEC_ENET_MII)
#define FEC_NAPI_IMASK FEC_ENET_MII
#define FEC_DEFAULT_IMASK (FEC_ENET_TXF | FEC_ENET_RXF)
#define FEC_RX_DISABLED_IMASK (FEC_DEFAULT_IMASK & (~FEC_ENET_RXF))

/* ENET interrupt coalescing macro define */
Expand Down Expand Up @@ -543,7 +542,6 @@ struct fec_enet_private {
int link;
int full_duplex;
int speed;
struct completion mdio_done;
int irq[FEC_IRQ_NUM];
bool bufdesc_ex;
int pause_flag;
Expand Down
85 changes: 49 additions & 36 deletions drivers/net/ethernet/freescale/fec_main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -976,8 +976,8 @@ fec_restart(struct net_device *ndev)
writel((__force u32)cpu_to_be32(temp_mac[1]),
fep->hwp + FEC_ADDR_HIGH);

/* Clear any outstanding interrupt. */
writel(0xffffffff, fep->hwp + FEC_IEVENT);
/* Clear any outstanding interrupt, except MDIO. */
writel((0xffffffff & ~FEC_ENET_MII), fep->hwp + FEC_IEVENT);

fec_enet_bd_init(ndev);

Expand Down Expand Up @@ -1123,7 +1123,7 @@ fec_restart(struct net_device *ndev)
if (fep->link)
writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
else
writel(FEC_ENET_MII, fep->hwp + FEC_IMASK);
writel(0, fep->hwp + FEC_IMASK);

/* Init the interrupt coalescing */
fec_enet_itr_coal_init(ndev);
Expand Down Expand Up @@ -1652,23 +1652,23 @@ fec_enet_interrupt(int irq, void *dev_id)
irqreturn_t ret = IRQ_NONE;

int_events = readl(fep->hwp + FEC_IEVENT);

/* Don't clear MDIO events, we poll for those */
int_events &= ~FEC_ENET_MII;

writel(int_events, fep->hwp + FEC_IEVENT);
fec_enet_collect_events(fep, int_events);

if ((fep->work_tx || fep->work_rx) && fep->link) {
ret = IRQ_HANDLED;

if (napi_schedule_prep(&fep->napi)) {
/* Disable the NAPI interrupts */
writel(FEC_NAPI_IMASK, fep->hwp + FEC_IMASK);
/* Disable interrupts */
writel(0, fep->hwp + FEC_IMASK);
__napi_schedule(&fep->napi);
}
}

if (int_events & FEC_ENET_MII) {
ret = IRQ_HANDLED;
complete(&fep->mdio_done);
}
return ret;
}

Expand Down Expand Up @@ -1818,20 +1818,31 @@ static void fec_enet_adjust_link(struct net_device *ndev)
phy_print_status(phy_dev);
}

static int fec_enet_mdio_wait(struct fec_enet_private *fep)
{
uint ievent;
int ret;

ret = readl_poll_timeout_atomic(fep->hwp + FEC_IEVENT, ievent,
ievent & FEC_ENET_MII, 2, 30000);

if (!ret)
writel(FEC_ENET_MII, fep->hwp + FEC_IEVENT);

return ret;
}

static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
{
struct fec_enet_private *fep = bus->priv;
struct device *dev = &fep->pdev->dev;
unsigned long time_left;
int ret = 0, frame_start, frame_addr, frame_op;
bool is_c45 = !!(regnum & MII_ADDR_C45);

ret = pm_runtime_get_sync(dev);
if (ret < 0)
return ret;

reinit_completion(&fep->mdio_done);

if (is_c45) {
frame_start = FEC_MMFR_ST_C45;

Expand All @@ -1843,11 +1854,9 @@ static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
fep->hwp + FEC_MII_DATA);

/* wait for end of transfer */
time_left = wait_for_completion_timeout(&fep->mdio_done,
usecs_to_jiffies(FEC_MII_TIMEOUT));
if (time_left == 0) {
ret = fec_enet_mdio_wait(fep);
if (ret) {
netdev_err(fep->netdev, "MDIO address write timeout\n");
ret = -ETIMEDOUT;
goto out;
}

Expand All @@ -1866,11 +1875,9 @@ static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
FEC_MMFR_TA, fep->hwp + FEC_MII_DATA);

/* wait for end of transfer */
time_left = wait_for_completion_timeout(&fep->mdio_done,
usecs_to_jiffies(FEC_MII_TIMEOUT));
if (time_left == 0) {
ret = fec_enet_mdio_wait(fep);
if (ret) {
netdev_err(fep->netdev, "MDIO read timeout\n");
ret = -ETIMEDOUT;
goto out;
}

Expand All @@ -1888,7 +1895,6 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
{
struct fec_enet_private *fep = bus->priv;
struct device *dev = &fep->pdev->dev;
unsigned long time_left;
int ret, frame_start, frame_addr;
bool is_c45 = !!(regnum & MII_ADDR_C45);

Expand All @@ -1898,8 +1904,6 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
else
ret = 0;

reinit_completion(&fep->mdio_done);

if (is_c45) {
frame_start = FEC_MMFR_ST_C45;

Expand All @@ -1911,11 +1915,9 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
fep->hwp + FEC_MII_DATA);

/* wait for end of transfer */
time_left = wait_for_completion_timeout(&fep->mdio_done,
usecs_to_jiffies(FEC_MII_TIMEOUT));
if (time_left == 0) {
ret = fec_enet_mdio_wait(fep);
if (ret) {
netdev_err(fep->netdev, "MDIO address write timeout\n");
ret = -ETIMEDOUT;
goto out;
}
} else {
Expand All @@ -1931,12 +1933,9 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
fep->hwp + FEC_MII_DATA);

/* wait for end of transfer */
time_left = wait_for_completion_timeout(&fep->mdio_done,
usecs_to_jiffies(FEC_MII_TIMEOUT));
if (time_left == 0) {
ret = fec_enet_mdio_wait(fep);
if (ret)
netdev_err(fep->netdev, "MDIO write timeout\n");
ret = -ETIMEDOUT;
}

out:
pm_runtime_mark_last_busy(dev);
Expand Down Expand Up @@ -2065,9 +2064,11 @@ static int fec_enet_mii_init(struct platform_device *pdev)
static struct mii_bus *fec0_mii_bus;
struct net_device *ndev = platform_get_drvdata(pdev);
struct fec_enet_private *fep = netdev_priv(ndev);
bool suppress_preamble = false;
struct device_node *node;
int err = -ENXIO;
u32 mii_speed, holdtime;
u32 bus_freq;

/*
* The i.MX28 dual fec interfaces are not equal.
Expand Down Expand Up @@ -2095,15 +2096,23 @@ static int fec_enet_mii_init(struct platform_device *pdev)
return -ENOENT;
}

bus_freq = 2500000; /* 2.5MHz by default */
node = of_get_child_by_name(pdev->dev.of_node, "mdio");
if (node) {
of_property_read_u32(node, "clock-frequency", &bus_freq);
suppress_preamble = of_property_read_bool(node,
"suppress-preamble");
}

/*
* Set MII speed to 2.5 MHz (= clk_get_rate() / 2 * phy_speed)
* Set MII speed (= clk_get_rate() / 2 * phy_speed)
*
* The formula for FEC MDC is 'ref_freq / (MII_SPEED x 2)' while
* for ENET-MAC is 'ref_freq / ((MII_SPEED + 1) x 2)'. The i.MX28
* Reference Manual has an error on this, and gets fixed on i.MX6Q
* document.
*/
mii_speed = DIV_ROUND_UP(clk_get_rate(fep->clk_ipg), 5000000);
mii_speed = DIV_ROUND_UP(clk_get_rate(fep->clk_ipg), bus_freq * 2);
if (fep->quirks & FEC_QUIRK_ENET_MAC)
mii_speed--;
if (mii_speed > 63) {
Expand All @@ -2130,8 +2139,14 @@ static int fec_enet_mii_init(struct platform_device *pdev)

fep->phy_speed = mii_speed << 1 | holdtime << 8;

if (suppress_preamble)
fep->phy_speed |= BIT(7);

writel(fep->phy_speed, fep->hwp + FEC_MII_SPEED);

/* Clear any pending transaction complete indication */
writel(FEC_ENET_MII, fep->hwp + FEC_IEVENT);

fep->mii_bus = mdiobus_alloc();
if (fep->mii_bus == NULL) {
err = -ENOMEM;
Expand All @@ -2146,7 +2161,6 @@ static int fec_enet_mii_init(struct platform_device *pdev)
fep->mii_bus->priv = fep;
fep->mii_bus->parent = &pdev->dev;

node = of_get_child_by_name(pdev->dev.of_node, "mdio");
err = of_mdiobus_register(fep->mii_bus, node);
of_node_put(node);
if (err)
Expand Down Expand Up @@ -3674,7 +3688,6 @@ fec_probe(struct platform_device *pdev)
fep->irq[i] = irq;
}

init_completion(&fep->mdio_done);
ret = fec_enet_mii_init(pdev);
if (ret)
goto failed_mii_init;
Expand Down

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