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linux_dsm_epyc7002/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
Martin Blumenstingl 433c6cab9d net: stmmac: dwmac-meson8b: fix setting the RGMII TX clock on Meson8b 
Meson8b only supports MPLL2 as clock input. The rate of the MPLL2 clock
set by Odroid-C1's u-boot is close to (but not exactly) 500MHz. The
exact rate is 500002394Hz, which is calculated in
drivers/clk/meson/clk-mpll.c using the following formula:
DIV_ROUND_UP_ULL((u64)parent_rate * SDM_DEN, (SDM_DEN * n2) + sdm)
Odroid-C1's u-boot configures MPLL2 with the following values:
- SDM_DEN = 16384
- SDM = 1638
- N2 = 5

The 250MHz clock (m250_div) inside dwmac-meson8b driver is derived from
the MPLL2 clock. Due to MPLL2 running slightly faster than 500MHz the
common clock framework chooses a divider which is too big to generate
the 250MHz clock (a divider of 2 would be needed, but this is rounded up
to a divider of 3). This breaks the RTL8211F RGMII PHY on Odroid-C1
because it requires a (close to) 125MHz RGMII TX clock (on Gbit speeds,
the IP block internally divides that down to 25MHz on 100Mbit/s
connections and 2.5MHz on 10Mbit/s connections - we don't need any
special configuration for that).

Round the divider to the closest value to prevent this issue on Meson8b.
This means we'll now end up with a clock rate for the RGMII TX clock of
125001197Hz (= 125MHz plus 1197Hz), which is close-enough to 125MHz.
This has no effect on the Meson GX SoCs since there fclk_div2 is used as
input clock, which has a rate of 1000MHz (and thus is divisible cleanly
to 250MHz and 125MHz).

Fixes: 566e825162 ("net: stmmac: add a glue driver for the Amlogic Meson 8b / GXBB DWMAC")
Reported-by: Emiliano Ingrassia <ingrassia@epigenesys.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
Tested-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-17 14:41:05 -05:00

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/*
* Amlogic Meson8b and GXBB DWMAC glue layer
*
* Copyright (C) 2016 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/device.h>
#include <linux/ethtool.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/of_net.h>
#include <linux/mfd/syscon.h>
#include <linux/platform_device.h>
#include <linux/stmmac.h>
#include "stmmac_platform.h"
#define PRG_ETH0 0x0
#define PRG_ETH0_RGMII_MODE BIT(0)
/* mux to choose between fclk_div2 (bit unset) and mpll2 (bit set) */
#define PRG_ETH0_CLK_M250_SEL_SHIFT 4
#define PRG_ETH0_CLK_M250_SEL_MASK GENMASK(4, 4)
#define PRG_ETH0_TXDLY_SHIFT 5
#define PRG_ETH0_TXDLY_MASK GENMASK(6, 5)
/* divider for the result of m250_sel */
#define PRG_ETH0_CLK_M250_DIV_SHIFT 7
#define PRG_ETH0_CLK_M250_DIV_WIDTH 3
#define PRG_ETH0_RGMII_TX_CLK_EN 10
#define PRG_ETH0_INVERTED_RMII_CLK BIT(11)
#define PRG_ETH0_TX_AND_PHY_REF_CLK BIT(12)
#define MUX_CLK_NUM_PARENTS 2
struct meson8b_dwmac {
struct platform_device *pdev;
void __iomem *regs;
phy_interface_t phy_mode;
struct clk_mux m250_mux;
struct clk *m250_mux_clk;
struct clk *m250_mux_parent[MUX_CLK_NUM_PARENTS];
struct clk_divider m250_div;
struct clk *m250_div_clk;
struct clk_fixed_factor fixed_div2;
struct clk *fixed_div2_clk;
struct clk_gate rgmii_tx_en;
struct clk *rgmii_tx_en_clk;
u32 tx_delay_ns;
};
static void meson8b_dwmac_mask_bits(struct meson8b_dwmac *dwmac, u32 reg,
u32 mask, u32 value)
{
u32 data;
data = readl(dwmac->regs + reg);
data &= ~mask;
data |= (value & mask);
writel(data, dwmac->regs + reg);
}
static int meson8b_init_rgmii_tx_clk(struct meson8b_dwmac *dwmac)
{
struct clk_init_data init;
int i, ret;
struct device *dev = &dwmac->pdev->dev;
char clk_name[32];
const char *clk_div_parents[1];
const char *mux_parent_names[MUX_CLK_NUM_PARENTS];
/* get the mux parents from DT */
for (i = 0; i < MUX_CLK_NUM_PARENTS; i++) {
char name[16];
snprintf(name, sizeof(name), "clkin%d", i);
dwmac->m250_mux_parent[i] = devm_clk_get(dev, name);
if (IS_ERR(dwmac->m250_mux_parent[i])) {
ret = PTR_ERR(dwmac->m250_mux_parent[i]);
if (ret != -EPROBE_DEFER)
dev_err(dev, "Missing clock %s\n", name);
return ret;
}
mux_parent_names[i] =
__clk_get_name(dwmac->m250_mux_parent[i]);
}
/* create the m250_mux */
snprintf(clk_name, sizeof(clk_name), "%s#m250_sel", dev_name(dev));
init.name = clk_name;
init.ops = &clk_mux_ops;
init.flags = 0;
init.parent_names = mux_parent_names;
init.num_parents = MUX_CLK_NUM_PARENTS;
dwmac->m250_mux.reg = dwmac->regs + PRG_ETH0;
dwmac->m250_mux.shift = PRG_ETH0_CLK_M250_SEL_SHIFT;
dwmac->m250_mux.mask = PRG_ETH0_CLK_M250_SEL_MASK;
dwmac->m250_mux.flags = 0;
dwmac->m250_mux.table = NULL;
dwmac->m250_mux.hw.init = &init;
dwmac->m250_mux_clk = devm_clk_register(dev, &dwmac->m250_mux.hw);
if (WARN_ON(IS_ERR(dwmac->m250_mux_clk)))
return PTR_ERR(dwmac->m250_mux_clk);
/* create the m250_div */
snprintf(clk_name, sizeof(clk_name), "%s#m250_div", dev_name(dev));
init.name = devm_kstrdup(dev, clk_name, GFP_KERNEL);
init.ops = &clk_divider_ops;
init.flags = CLK_SET_RATE_PARENT;
clk_div_parents[0] = __clk_get_name(dwmac->m250_mux_clk);
init.parent_names = clk_div_parents;
init.num_parents = ARRAY_SIZE(clk_div_parents);
dwmac->m250_div.reg = dwmac->regs + PRG_ETH0;
dwmac->m250_div.shift = PRG_ETH0_CLK_M250_DIV_SHIFT;
dwmac->m250_div.width = PRG_ETH0_CLK_M250_DIV_WIDTH;
dwmac->m250_div.hw.init = &init;
dwmac->m250_div.flags = CLK_DIVIDER_ONE_BASED |
CLK_DIVIDER_ALLOW_ZERO |
CLK_DIVIDER_ROUND_CLOSEST;
dwmac->m250_div_clk = devm_clk_register(dev, &dwmac->m250_div.hw);
if (WARN_ON(IS_ERR(dwmac->m250_div_clk)))
return PTR_ERR(dwmac->m250_div_clk);
/* create the fixed_div2 */
snprintf(clk_name, sizeof(clk_name), "%s#fixed_div2", dev_name(dev));
init.name = devm_kstrdup(dev, clk_name, GFP_KERNEL);
init.ops = &clk_fixed_factor_ops;
init.flags = CLK_SET_RATE_PARENT;
clk_div_parents[0] = __clk_get_name(dwmac->m250_div_clk);
init.parent_names = clk_div_parents;
init.num_parents = ARRAY_SIZE(clk_div_parents);
dwmac->fixed_div2.mult = 1;
dwmac->fixed_div2.div = 2;
dwmac->fixed_div2.hw.init = &init;
dwmac->fixed_div2_clk = devm_clk_register(dev, &dwmac->fixed_div2.hw);
if (WARN_ON(IS_ERR(dwmac->fixed_div2_clk)))
return PTR_ERR(dwmac->fixed_div2_clk);
/* create the rgmii_tx_en */
init.name = devm_kasprintf(dev, GFP_KERNEL, "%s#rgmii_tx_en",
dev_name(dev));
init.ops = &clk_gate_ops;
init.flags = CLK_SET_RATE_PARENT;
clk_div_parents[0] = __clk_get_name(dwmac->fixed_div2_clk);
init.parent_names = clk_div_parents;
init.num_parents = ARRAY_SIZE(clk_div_parents);
dwmac->rgmii_tx_en.reg = dwmac->regs + PRG_ETH0;
dwmac->rgmii_tx_en.bit_idx = PRG_ETH0_RGMII_TX_CLK_EN;
dwmac->rgmii_tx_en.hw.init = &init;
dwmac->rgmii_tx_en_clk = devm_clk_register(dev,
&dwmac->rgmii_tx_en.hw);
if (WARN_ON(IS_ERR(dwmac->rgmii_tx_en_clk)))
return PTR_ERR(dwmac->rgmii_tx_en_clk);
return 0;
}
static int meson8b_init_prg_eth(struct meson8b_dwmac *dwmac)
{
int ret;
u8 tx_dly_val = 0;
switch (dwmac->phy_mode) {
case PHY_INTERFACE_MODE_RGMII:
case PHY_INTERFACE_MODE_RGMII_RXID:
/* TX clock delay in ns = "8ns / 4 * tx_dly_val" (where
* 8ns are exactly one cycle of the 125MHz RGMII TX clock):
* 0ns = 0x0, 2ns = 0x1, 4ns = 0x2, 6ns = 0x3
*/
tx_dly_val = dwmac->tx_delay_ns >> 1;
/* fall through */
case PHY_INTERFACE_MODE_RGMII_ID:
case PHY_INTERFACE_MODE_RGMII_TXID:
/* enable RGMII mode */
meson8b_dwmac_mask_bits(dwmac, PRG_ETH0, PRG_ETH0_RGMII_MODE,
PRG_ETH0_RGMII_MODE);
/* only relevant for RMII mode -> disable in RGMII mode */
meson8b_dwmac_mask_bits(dwmac, PRG_ETH0,
PRG_ETH0_INVERTED_RMII_CLK, 0);
meson8b_dwmac_mask_bits(dwmac, PRG_ETH0, PRG_ETH0_TXDLY_MASK,
tx_dly_val << PRG_ETH0_TXDLY_SHIFT);
/* Configure the 125MHz RGMII TX clock, the IP block changes
* the output automatically (= without us having to configure
* a register) based on the line-speed (125MHz for Gbit speeds,
* 25MHz for 100Mbit/s and 2.5MHz for 10Mbit/s).
*/
ret = clk_set_rate(dwmac->rgmii_tx_en_clk, 125 * 1000 * 1000);
if (ret) {
dev_err(&dwmac->pdev->dev,
"failed to set RGMII TX clock\n");
return ret;
}
ret = clk_prepare_enable(dwmac->rgmii_tx_en_clk);
if (ret) {
dev_err(&dwmac->pdev->dev,
"failed to enable the RGMII TX clock\n");
return ret;
}
break;
case PHY_INTERFACE_MODE_RMII:
/* disable RGMII mode -> enables RMII mode */
meson8b_dwmac_mask_bits(dwmac, PRG_ETH0, PRG_ETH0_RGMII_MODE,
0);
/* invert internal clk_rmii_i to generate 25/2.5 tx_rx_clk */
meson8b_dwmac_mask_bits(dwmac, PRG_ETH0,
PRG_ETH0_INVERTED_RMII_CLK,
PRG_ETH0_INVERTED_RMII_CLK);
/* TX clock delay cannot be configured in RMII mode */
meson8b_dwmac_mask_bits(dwmac, PRG_ETH0, PRG_ETH0_TXDLY_MASK,
0);
break;
default:
dev_err(&dwmac->pdev->dev, "unsupported phy-mode %s\n",
phy_modes(dwmac->phy_mode));
return -EINVAL;
}
/* enable TX_CLK and PHY_REF_CLK generator */
meson8b_dwmac_mask_bits(dwmac, PRG_ETH0, PRG_ETH0_TX_AND_PHY_REF_CLK,
PRG_ETH0_TX_AND_PHY_REF_CLK);
return 0;
}
static int meson8b_dwmac_probe(struct platform_device *pdev)
{
struct plat_stmmacenet_data *plat_dat;
struct stmmac_resources stmmac_res;
struct resource *res;
struct meson8b_dwmac *dwmac;
int ret;
ret = stmmac_get_platform_resources(pdev, &stmmac_res);
if (ret)
return ret;
plat_dat = stmmac_probe_config_dt(pdev, &stmmac_res.mac);
if (IS_ERR(plat_dat))
return PTR_ERR(plat_dat);
dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
if (!dwmac) {
ret = -ENOMEM;
goto err_remove_config_dt;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
dwmac->regs = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(dwmac->regs)) {
ret = PTR_ERR(dwmac->regs);
goto err_remove_config_dt;
}
dwmac->pdev = pdev;
dwmac->phy_mode = of_get_phy_mode(pdev->dev.of_node);
if (dwmac->phy_mode < 0) {
dev_err(&pdev->dev, "missing phy-mode property\n");
ret = -EINVAL;
goto err_remove_config_dt;
}
/* use 2ns as fallback since this value was previously hardcoded */
if (of_property_read_u32(pdev->dev.of_node, "amlogic,tx-delay-ns",
&dwmac->tx_delay_ns))
dwmac->tx_delay_ns = 2;
ret = meson8b_init_rgmii_tx_clk(dwmac);
if (ret)
goto err_remove_config_dt;
ret = meson8b_init_prg_eth(dwmac);
if (ret)
goto err_remove_config_dt;
plat_dat->bsp_priv = dwmac;
ret = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
if (ret)
goto err_clk_disable;
return 0;
err_clk_disable:
if (phy_interface_mode_is_rgmii(dwmac->phy_mode))
clk_disable_unprepare(dwmac->rgmii_tx_en_clk);
err_remove_config_dt:
stmmac_remove_config_dt(pdev, plat_dat);
return ret;
}
static int meson8b_dwmac_remove(struct platform_device *pdev)
{
struct meson8b_dwmac *dwmac = get_stmmac_bsp_priv(&pdev->dev);
if (phy_interface_mode_is_rgmii(dwmac->phy_mode))
clk_disable_unprepare(dwmac->rgmii_tx_en_clk);
return stmmac_pltfr_remove(pdev);
}
static const struct of_device_id meson8b_dwmac_match[] = {
{ .compatible = "amlogic,meson8b-dwmac" },
{ .compatible = "amlogic,meson-gxbb-dwmac" },
{ }
};
MODULE_DEVICE_TABLE(of, meson8b_dwmac_match);
static struct platform_driver meson8b_dwmac_driver = {
.probe = meson8b_dwmac_probe,
.remove = meson8b_dwmac_remove,
.driver = {
.name = "meson8b-dwmac",
.pm = &stmmac_pltfr_pm_ops,
.of_match_table = meson8b_dwmac_match,
},
};
module_platform_driver(meson8b_dwmac_driver);
MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
MODULE_DESCRIPTION("Amlogic Meson8b and GXBB DWMAC glue layer");
MODULE_LICENSE("GPL v2");
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