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ar71xx: fix QCA955X SGMII link loss

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The QCA955X is affected by a hardware bug which causes link-loss of the
SGMII link between SoC and PHY. This happens on change of link-state or
speed.

It is not really known what causes this bug. It definitely occurs when
using a AR8033 Gigabit Ethernet PHY.

Qualcomm solves this Bug in a similar fashion. We need to apply the fix
on a per-device base via platform-data as performing the fixup work will
break connectivity in case the SGMII interface is connected to a Switch.

This bug was first proposed to be fixed by Sven Eckelmann in 2016.
 https://patchwork.ozlabs.org/patch/604782/

Based-on-patch-by: Sven Eckelmann <sven.eckelmann@open-mesh.com>
Signed-off-by: David Bauer <mail@david-bauer.net>
This commit is contained in:
David Bauer
2018-08-06 16:15:04 +02:00
committed by John Crispin
parent fbe17867da
commit f4f99ec973
5 changed files with 127 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
View File

@@ -66,6 +66,8 @@
#define AG71XX_TX_RING_SIZE_MAX 128
#define AG71XX_RX_RING_SIZE_MAX 256
#define QCA955X_SGMII_LINK_WAR_MAX_TRY 10
#ifdef CONFIG_AG71XX_DEBUG
#define DBG(fmt, args...) pr_debug(fmt, ## args)
#else

79
target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
View File

@@ -31,6 +31,7 @@ MODULE_PARM_DESC(msg_level, "Message level (-1=defaults,0=none,...,16=all)");
#define ETH_SWITCH_HEADER_LEN 2
static int ag71xx_tx_packets(struct ag71xx *ag, bool flush);
static void ag71xx_qca955x_sgmii_init(void);
static inline unsigned int ag71xx_max_frame_len(unsigned int mtu)
{
@@ -610,6 +611,9 @@ __ag71xx_link_adjust(struct ag71xx *ag, bool update)
if (update && pdata->set_speed)
pdata->set_speed(ag->speed);
if (update && pdata->enable_sgmii_fixup)
ag71xx_qca955x_sgmii_init();
ag71xx_wr(ag, AG71XX_REG_MAC_CFG2, cfg2);
ag71xx_wr(ag, AG71XX_REG_FIFO_CFG5, fifo5);
ag71xx_wr(ag, AG71XX_REG_MAC_IFCTL, ifctl);
@@ -913,6 +917,81 @@ static void ag71xx_tx_timeout(struct net_device *dev)
schedule_delayed_work(&ag->restart_work, 1);
}
static void ag71xx_bit_set(void __iomem *reg, u32 bit)
{
u32 val = __raw_readl(reg) | bit;
__raw_writel(val, reg);
__raw_readl(reg);
}
static void ag71xx_bit_clear(void __iomem *reg, u32 bit)
{
u32 val = __raw_readl(reg) & ~bit;
__raw_writel(val, reg);
__raw_readl(reg);
}
static void ag71xx_qca955x_sgmii_init()
{
void __iomem *gmac_base;
u32 mr_an_status, sgmii_status;
u8 tries = 0;
gmac_base = ioremap_nocache(QCA955X_GMAC_BASE, QCA955X_GMAC_SIZE);
if (!gmac_base)
goto sgmii_out;
mr_an_status = __raw_readl(gmac_base + QCA955X_GMAC_REG_MR_AN_STATUS);
if (!(mr_an_status & QCA955X_MR_AN_STATUS_AN_ABILITY))
goto sgmii_out;
__raw_writel(QCA955X_SGMII_RESET_RX_CLK_N_RESET ,
gmac_base + QCA955X_GMAC_REG_SGMII_RESET);
__raw_readl(gmac_base + QCA955X_GMAC_REG_SGMII_RESET);
udelay(10);
/* Init sequence */
ag71xx_bit_set(gmac_base + QCA955X_GMAC_REG_SGMII_RESET,
QCA955X_SGMII_RESET_HW_RX_125M_N);
udelay(10);
ag71xx_bit_set(gmac_base + QCA955X_GMAC_REG_SGMII_RESET,
QCA955X_SGMII_RESET_RX_125M_N);
udelay(10);
ag71xx_bit_set(gmac_base + QCA955X_GMAC_REG_SGMII_RESET,
QCA955X_SGMII_RESET_TX_125M_N);
udelay(10);
ag71xx_bit_set(gmac_base + QCA955X_GMAC_REG_SGMII_RESET,
QCA955X_SGMII_RESET_RX_CLK_N);
udelay(10);
ag71xx_bit_set(gmac_base + QCA955X_GMAC_REG_SGMII_RESET,
QCA955X_SGMII_RESET_TX_CLK_N);
udelay(10);
do {
ag71xx_bit_set(gmac_base + QCA955X_GMAC_REG_MR_AN_CONTROL,
QCA955X_MR_AN_CONTROL_PHY_RESET |
QCA955X_MR_AN_CONTROL_AN_ENABLE);
udelay(100);
ag71xx_bit_clear(gmac_base + QCA955X_GMAC_REG_MR_AN_CONTROL,
QCA955X_MR_AN_CONTROL_PHY_RESET);
mdelay(10);
sgmii_status = __raw_readl(gmac_base + QCA955X_GMAC_REG_SGMII_DEBUG) & 0xF;
if (tries++ >= QCA955X_SGMII_LINK_WAR_MAX_TRY) {
pr_warn("ag71xx: max retries for SGMII fixup exceeded!\n");
break;
}
} while (!(sgmii_status == 0xf || sgmii_status == 0x10));
sgmii_out:
iounmap(gmac_base);
}
static void ag71xx_restart_work_func(struct work_struct *work)
{
struct ag71xx *ag = container_of(work, struct ag71xx, restart_work.work);