From 489d4d7713d1cad40b1049720b44d08f53918b30 Mon Sep 17 00:00:00 2001 From: Robert Hancock Date: Thu, 6 Jun 2019 16:28:12 -0600 Subject: [PATCH] net: axienet: Cleanup DMA device reset and halt process The Xilinx DMA blocks each have their own reset register, but they both reset the entire DMA engine, so only one of them needs to be reset. Also, when stopping the device, we need to not just command the DMA blocks to stop, but wait for them to stop, and trigger a device reset to ensure that they are completely stopped. Signed-off-by: Robert Hancock Signed-off-by: David S. Miller --- drivers/net/ethernet/xilinx/xilinx_axienet.h | 2 + .../net/ethernet/xilinx/xilinx_axienet_main.c | 54 ++++++++++++++----- 2 files changed, 42 insertions(+), 14 deletions(-) diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet.h b/drivers/net/ethernet/xilinx/xilinx_axienet.h index 4a135ed6e8a3..1ffb113e2c29 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet.h +++ b/drivers/net/ethernet/xilinx/xilinx_axienet.h @@ -83,6 +83,8 @@ #define XAXIDMA_CR_RUNSTOP_MASK 0x00000001 /* Start/stop DMA channel */ #define XAXIDMA_CR_RESET_MASK 0x00000004 /* Reset DMA engine */ +#define XAXIDMA_SR_HALT_MASK 0x00000001 /* Indicates DMA channel halted */ + #define XAXIDMA_BD_NDESC_OFFSET 0x00 /* Next descriptor pointer */ #define XAXIDMA_BD_BUFA_OFFSET 0x08 /* Buffer address */ #define XAXIDMA_BD_CTRL_LEN_OFFSET 0x18 /* Control/buffer length */ diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index e735ca7b5df0..bdc6e8047959 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -434,17 +434,20 @@ static void axienet_setoptions(struct net_device *ndev, u32 options) lp->options |= options; } -static void __axienet_device_reset(struct axienet_local *lp, off_t offset) +static void __axienet_device_reset(struct axienet_local *lp) { u32 timeout; /* Reset Axi DMA. This would reset Axi Ethernet core as well. The reset * process of Axi DMA takes a while to complete as all pending * commands/transfers will be flushed or completed during this * reset process. + * Note that even though both TX and RX have their own reset register, + * they both reset the entire DMA core, so only one needs to be used. */ - axienet_dma_out32(lp, offset, XAXIDMA_CR_RESET_MASK); + axienet_dma_out32(lp, XAXIDMA_TX_CR_OFFSET, XAXIDMA_CR_RESET_MASK); timeout = DELAY_OF_ONE_MILLISEC; - while (axienet_dma_in32(lp, offset) & XAXIDMA_CR_RESET_MASK) { + while (axienet_dma_in32(lp, XAXIDMA_TX_CR_OFFSET) & + XAXIDMA_CR_RESET_MASK) { udelay(1); if (--timeout == 0) { netdev_err(lp->ndev, "%s: DMA reset timeout!\n", @@ -470,8 +473,7 @@ static void axienet_device_reset(struct net_device *ndev) u32 axienet_status; struct axienet_local *lp = netdev_priv(ndev); - __axienet_device_reset(lp, XAXIDMA_TX_CR_OFFSET); - __axienet_device_reset(lp, XAXIDMA_RX_CR_OFFSET); + __axienet_device_reset(lp); lp->max_frm_size = XAE_MAX_VLAN_FRAME_SIZE; lp->options |= XAE_OPTION_VLAN; @@ -981,20 +983,45 @@ err_tx_irq: */ static int axienet_stop(struct net_device *ndev) { - u32 cr; + u32 cr, sr; + int count; struct axienet_local *lp = netdev_priv(ndev); dev_dbg(&ndev->dev, "axienet_close()\n"); - cr = axienet_dma_in32(lp, XAXIDMA_RX_CR_OFFSET); - axienet_dma_out32(lp, XAXIDMA_RX_CR_OFFSET, - cr & (~XAXIDMA_CR_RUNSTOP_MASK)); - cr = axienet_dma_in32(lp, XAXIDMA_TX_CR_OFFSET); - axienet_dma_out32(lp, XAXIDMA_TX_CR_OFFSET, - cr & (~XAXIDMA_CR_RUNSTOP_MASK)); axienet_setoptions(ndev, lp->options & ~(XAE_OPTION_TXEN | XAE_OPTION_RXEN)); + cr = axienet_dma_in32(lp, XAXIDMA_RX_CR_OFFSET); + cr &= ~(XAXIDMA_CR_RUNSTOP_MASK | XAXIDMA_IRQ_ALL_MASK); + axienet_dma_out32(lp, XAXIDMA_RX_CR_OFFSET, cr); + + cr = axienet_dma_in32(lp, XAXIDMA_TX_CR_OFFSET); + cr &= ~(XAXIDMA_CR_RUNSTOP_MASK | XAXIDMA_IRQ_ALL_MASK); + axienet_dma_out32(lp, XAXIDMA_TX_CR_OFFSET, cr); + + axienet_iow(lp, XAE_IE_OFFSET, 0); + + /* Give DMAs a chance to halt gracefully */ + sr = axienet_dma_in32(lp, XAXIDMA_RX_SR_OFFSET); + for (count = 0; !(sr & XAXIDMA_SR_HALT_MASK) && count < 5; ++count) { + msleep(20); + sr = axienet_dma_in32(lp, XAXIDMA_RX_SR_OFFSET); + } + + sr = axienet_dma_in32(lp, XAXIDMA_TX_SR_OFFSET); + for (count = 0; !(sr & XAXIDMA_SR_HALT_MASK) && count < 5; ++count) { + msleep(20); + sr = axienet_dma_in32(lp, XAXIDMA_TX_SR_OFFSET); + } + + /* Do a reset to ensure DMA is really stopped */ + mutex_lock(&lp->mii_bus->mdio_lock); + axienet_mdio_disable(lp); + __axienet_device_reset(lp); + axienet_mdio_enable(lp); + mutex_unlock(&lp->mii_bus->mdio_lock); + tasklet_kill(&lp->dma_err_tasklet); free_irq(lp->tx_irq, ndev); @@ -1326,8 +1353,7 @@ static void axienet_dma_err_handler(unsigned long data) */ mutex_lock(&lp->mii_bus->mdio_lock); axienet_mdio_disable(lp); - __axienet_device_reset(lp, XAXIDMA_TX_CR_OFFSET); - __axienet_device_reset(lp, XAXIDMA_RX_CR_OFFSET); + __axienet_device_reset(lp); axienet_mdio_enable(lp); mutex_unlock(&lp->mii_bus->mdio_lock); -- 2.30.2