[PATCH net-next v2 10/18] net: macb: remove illusion about TBQPH/RBQPH being per-queue
From: Théo Lebrun <theo.lebrun@bootlin.com>
Date: 2025-06-27 09:09:45
Also in:
linux-devicetree, linux-mips, linux-riscv, lkml
Subsystem:
atmel macb ethernet driver, networking drivers, the rest · Maintainers:
Théo Lebrun, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
The MACB driver acts as if TBQPH/RBQPH are configurable on a per queue
basis; this is a lie. A single register configures the upper 32 bits of
each DMA descriptor buffers for all queues.
Concrete actions:
- Drop GEM_TBQPH/GEM_RBQPH macros which have a queue index argument.
Only use MACB_TBQPH/MACB_RBQPH constants.
- Drop struct macb_queue->TBQPH/RBQPH fields.
- In macb_init_buffers(): do a single write to TBQPH and RBQPH for all
queues instead of a write per queue.
- In macb_tx_error_task(): drop the write to TBQPH.
- In macb_alloc_consistent(): if allocations give different upper
32-bits, fail. Previously, it would have lead to silent memory
corruption as queues would have used the upper 32 bits of the alloc
from queue 0 and their own low 32 bits.
- In macb_suspend(): if we use the tie off descriptor for suspend, do
the write once for all queues instead of once per queue.
Fixes: fff8019a08b6 ("net: macb: Add 64 bit addressing support for GEM")
Fixes: ae1f2a56d273 ("net: macb: Added support for many RX queues")
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
---
drivers/net/ethernet/cadence/macb.h | 4 ----
drivers/net/ethernet/cadence/macb_main.c | 36 +++++++++++++-------------------
2 files changed, 14 insertions(+), 26 deletions(-)
diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index 707b3286a6b8408a3bc4bbbcb1335ae8c3cd95ad..adc70b6efd52b0b11e436c2c95bb5108c40f3490 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h@@ -209,10 +209,8 @@ #define GEM_ISR(hw_q) (0x0400 + ((hw_q) << 2)) #define GEM_TBQP(hw_q) (0x0440 + ((hw_q) << 2)) -#define GEM_TBQPH(hw_q) (0x04C8) #define GEM_RBQP(hw_q) (0x0480 + ((hw_q) << 2)) #define GEM_RBQS(hw_q) (0x04A0 + ((hw_q) << 2)) -#define GEM_RBQPH(hw_q) (0x04D4) #define GEM_IER(hw_q) (0x0600 + ((hw_q) << 2)) #define GEM_IDR(hw_q) (0x0620 + ((hw_q) << 2)) #define GEM_IMR(hw_q) (0x0640 + ((hw_q) << 2))
@@ -1208,10 +1206,8 @@ struct macb_queue { unsigned int IDR; unsigned int IMR; unsigned int TBQP; - unsigned int TBQPH; unsigned int RBQS; unsigned int RBQP; - unsigned int RBQPH; /* Lock to protect tx_head and tx_tail */ spinlock_t tx_ptr_lock;
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index a6633e076644089c796453f856a766299bae2ec6..d3b3635998cad095246edf8a75faebbcf7115355 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c@@ -482,15 +482,15 @@ static void macb_init_buffers(struct macb *bp) struct macb_queue *queue; unsigned int q; + if (macb_dma_is_64b(bp)) { + /* Single register for all queues' high 32 bits. */ + macb_writel(bp, RBQPH, upper_32_bits(bp->queues->rx_ring_dma)); + macb_writel(bp, TBQPH, upper_32_bits(bp->queues->tx_ring_dma)); + } + for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) { queue_writel(queue, RBQP, lower_32_bits(queue->rx_ring_dma)); - if (macb_dma_is_64b(bp)) - queue_writel(queue, RBQPH, - upper_32_bits(queue->rx_ring_dma)); queue_writel(queue, TBQP, lower_32_bits(queue->tx_ring_dma)); - if (macb_dma_is_64b(bp)) - queue_writel(queue, TBQPH, - upper_32_bits(queue->tx_ring_dma)); } }
@@ -1145,8 +1145,6 @@ static void macb_tx_error_task(struct work_struct *work) /* Reinitialize the TX desc queue */ queue_writel(queue, TBQP, lower_32_bits(queue->tx_ring_dma)); - if (macb_dma_is_64b(bp)) - queue_writel(queue, TBQPH, upper_32_bits(queue->tx_ring_dma)); /* Make TX ring reflect state of hardware */ queue->tx_head = 0; queue->tx_tail = 0;
@@ -2524,7 +2522,8 @@ static int macb_alloc_consistent(struct macb *bp) queue->tx_ring = dma_alloc_coherent(&bp->pdev->dev, size, &queue->tx_ring_dma, GFP_KERNEL); - if (!queue->tx_ring) + if (!queue->tx_ring || + upper_32_bits(queue->tx_ring_dma) != upper_32_bits(bp->queues->tx_ring_dma)) goto out_err; netdev_dbg(bp->dev, "Allocated TX ring for queue %u of %d bytes at %08lx (mapped %p)\n",
@@ -2539,7 +2538,8 @@ static int macb_alloc_consistent(struct macb *bp) size = RX_RING_BYTES(bp) + bp->rx_bd_rd_prefetch; queue->rx_ring = dma_alloc_coherent(&bp->pdev->dev, size, &queue->rx_ring_dma, GFP_KERNEL); - if (!queue->rx_ring) + if (!queue->rx_ring || + upper_32_bits(queue->rx_ring_dma) != upper_32_bits(bp->queues->rx_ring_dma)) goto out_err; netdev_dbg(bp->dev, "Allocated RX ring of %d bytes at %08lx (mapped %p)\n",
@@ -4269,10 +4269,6 @@ static int macb_init(struct platform_device *pdev) queue->TBQP = GEM_TBQP(hw_q - 1); queue->RBQP = GEM_RBQP(hw_q - 1); queue->RBQS = GEM_RBQS(hw_q - 1); - if (macb_dma_is_64b(bp)) { - queue->TBQPH = GEM_TBQPH(hw_q - 1); - queue->RBQPH = GEM_RBQPH(hw_q - 1); - } } else { /* queue0 uses legacy registers */ queue->ISR = MACB_ISR;
@@ -4281,10 +4277,6 @@ static int macb_init(struct platform_device *pdev) queue->IMR = MACB_IMR; queue->TBQP = MACB_TBQP; queue->RBQP = MACB_RBQP; - if (macb_dma_is_64b(bp)) { - queue->TBQPH = MACB_TBQPH; - queue->RBQPH = MACB_RBQPH; - } } /* get irq: here we use the linux queue index, not the hardware
@@ -5401,6 +5393,10 @@ static int __maybe_unused macb_suspend(struct device *dev) */ tmp = macb_readl(bp, NCR); macb_writel(bp, NCR, tmp & ~(MACB_BIT(TE) | MACB_BIT(RE))); +#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT + if (!(bp->caps & MACB_CAPS_QUEUE_DISABLE)) + macb_writel(bp, RBQPH, upper_32_bits(bp->rx_ring_tieoff_dma)); +#endif for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) { /* Disable RX queues */
@@ -5410,10 +5406,6 @@ static int __maybe_unused macb_suspend(struct device *dev) /* Tie off RX queues */ queue_writel(queue, RBQP, lower_32_bits(bp->rx_ring_tieoff_dma)); -#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT - queue_writel(queue, RBQPH, - upper_32_bits(bp->rx_ring_tieoff_dma)); -#endif } /* Disable all interrupts */ queue_writel(queue, IDR, -1);
--
2.50.0