[PATCH net-next 11/15] net: sgi: ioc3-eth: use dma-direct for dma allocations

From: Thomas Bogendoerfer
Date: Wed Aug 28 2019 - 10:03:40 EST

Replace the homegrown DMA memory allocation, which only works on
SGI-IP27 machines, with the generic dma allocations.

Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@xxxxxxx>
---
drivers/net/ethernet/sgi/ioc3-eth.c | 146 ++++++++++++++++++++++++++++--------
1 file changed, 114 insertions(+), 32 deletions(-)

diff --git a/drivers/net/ethernet/sgi/ioc3-eth.c b/drivers/net/ethernet/sgi/ioc3-eth.c
index ecd3bc135cc0..aea3fecfac24 100644
--- a/drivers/net/ethernet/sgi/ioc3-eth.c
+++ b/drivers/net/ethernet/sgi/ioc3-eth.c
@@ -36,7 +36,6 @@
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
-#include <linux/dma-mapping.h>
#include <linux/gfp.h>

#ifdef CONFIG_SERIAL_8250
@@ -49,6 +48,8 @@
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/skbuff.h>
+#include <linux/dma-direct.h>
+
#include <net/ip.h>

#include <asm/byteorder.h>
@@ -64,10 +65,12 @@
#define RX_BUFFS 64
#define RX_RING_ENTRIES 512 /* fixed in hardware */
#define RX_RING_MASK (RX_RING_ENTRIES - 1)
+#define RX_RING_SIZE (RX_RING_ENTRIES * sizeof(u64))

/* 128 TX buffers (not tunable) */
#define TX_RING_ENTRIES 128
#define TX_RING_MASK (TX_RING_ENTRIES - 1)
+#define TX_RING_SIZE (TX_RING_ENTRIES * sizeof(struct ioc3_etxd))

/* IOC3 does dma transfers in 128 byte blocks */
#define IOC3_DMA_XFER_LEN 128UL
@@ -83,9 +86,12 @@
struct ioc3_private {
struct ioc3_ethregs *regs;
struct ioc3 *all_regs;
+ struct device *dma_dev;
u32 *ssram;
unsigned long *rxr; /* pointer to receiver ring */
struct ioc3_etxd *txr;
+ dma_addr_t rxr_dma;
+ dma_addr_t txr_dma;
struct sk_buff *rx_skbs[RX_RING_ENTRIES];
struct sk_buff *tx_skbs[TX_RING_ENTRIES];
int rx_ci; /* RX consumer index */
@@ -125,9 +131,11 @@ static inline unsigned long aligned_rx_skb_addr(unsigned long addr)
return (~addr + 1) & (IOC3_DMA_XFER_LEN - 1UL);
}

-static inline int ioc3_alloc_skb(struct sk_buff **skb, struct ioc3_erxbuf **rxb)
+static inline int ioc3_alloc_skb(struct ioc3_private *ip, struct sk_buff **skb,
+ struct ioc3_erxbuf **rxb, dma_addr_t *rxb_dma)
{
struct sk_buff *new_skb;
+ dma_addr_t d;
int offset;

new_skb = alloc_skb(RX_BUF_SIZE + IOC3_DMA_XFER_LEN - 1, GFP_ATOMIC);
@@ -139,6 +147,14 @@ static inline int ioc3_alloc_skb(struct sk_buff **skb, struct ioc3_erxbuf **rxb)
if (offset)
skb_reserve(new_skb, offset);

+ d = dma_map_single(ip->dma_dev, new_skb->data,
+ RX_BUF_SIZE, DMA_FROM_DEVICE);
+
+ if (dma_mapping_error(ip->dma_dev, d)) {
+ dev_kfree_skb_any(new_skb);
+ return -ENOMEM;
+ }
+ *rxb_dma = d;
*rxb = (struct ioc3_erxbuf *)new_skb->data;
skb_reserve(new_skb, RX_OFFSET);
*skb = new_skb;
@@ -146,17 +162,22 @@ static inline int ioc3_alloc_skb(struct sk_buff **skb, struct ioc3_erxbuf **rxb)
return 0;
}

-static inline unsigned long ioc3_map(void *ptr, unsigned long vdev)
+#ifdef CONFIG_PCI_XTALK_BRIDGE
+static inline unsigned long ioc3_map(dma_addr_t addr, unsigned long attr)
{
-#ifdef CONFIG_SGI_IP27
- vdev <<= 57; /* Shift to PCI64_ATTR_VIRTUAL */
+ return (addr & ~PCI64_ATTR_BAR) | attr;
+}

- return vdev | (0xaUL << PCI64_ATTR_TARG_SHFT) | PCI64_ATTR_PREF |
- ((unsigned long)ptr & TO_PHYS_MASK);
+#define ERBAR_VAL (ERBAR_BARRIER_BIT << ERBAR_RXBARR_SHIFT)
#else
- return virt_to_bus(ptr);
-#endif
+static inline unsigned long ioc3_map(dma_addr_t addr, unsigned long attr)
+{
+ return addr;
}
+
+#define ERBAR_VAL 0
+#endif
+
#define IOC3_SIZE 0x100000

static inline u32 mcr_pack(u32 pulse, u32 sample)
@@ -523,6 +544,7 @@ static inline void ioc3_rx(struct net_device *dev)
int rx_entry, n_entry, len;
struct ioc3_erxbuf *rxb;
unsigned long *rxr;
+ dma_addr_t d;
u32 w0, err;

rxr = ip->rxr; /* Ring base */
@@ -540,12 +562,13 @@ static inline void ioc3_rx(struct net_device *dev)
skb_put(skb, len);
skb->protocol = eth_type_trans(skb, dev);

- if (ioc3_alloc_skb(&new_skb, &rxb)) {
+ if (ioc3_alloc_skb(ip, &new_skb, &rxb, &d)) {
/* Ouch, drop packet and just recycle packet
* to keep the ring filled.
*/
dev->stats.rx_dropped++;
new_skb = skb;
+ d = rxr[rx_entry];
goto next;
}

@@ -554,6 +577,9 @@ static inline void ioc3_rx(struct net_device *dev)
w0 & ERXBUF_IPCKSUM_MASK,
len);

+ dma_unmap_single(ip->dma_dev, rxr[rx_entry],
+ RX_BUF_SIZE, DMA_FROM_DEVICE);
+
netif_rx(skb);

ip->rx_skbs[rx_entry] = NULL; /* Poison */
@@ -566,15 +592,17 @@ static inline void ioc3_rx(struct net_device *dev)
* recycle it.
*/
new_skb = skb;
+ d = rxr[rx_entry];
dev->stats.rx_errors++;
}
if (err & ERXBUF_CRCERR) /* Statistics */
dev->stats.rx_crc_errors++;
if (err & ERXBUF_FRAMERR)
dev->stats.rx_frame_errors++;
+
next:
ip->rx_skbs[n_entry] = new_skb;
- rxr[n_entry] = cpu_to_be64(ioc3_map(rxb, 1));
+ rxr[n_entry] = cpu_to_be64(ioc3_map(d, PCI64_ATTR_BAR));
rxb->w0 = 0; /* Clear valid flag */
n_entry = (n_entry + 1) & RX_RING_MASK; /* Update erpir */

@@ -767,6 +795,26 @@ static void ioc3_mii_start(struct ioc3_private *ip)
add_timer(&ip->ioc3_timer);
}

+static inline void ioc3_tx_unmap(struct ioc3_private *ip, int entry)
+{
+ struct ioc3_etxd *desc;
+ u32 cmd, bufcnt, len;
+
+ desc = &ip->txr[entry];
+ cmd = be32_to_cpu(desc->cmd);
+ bufcnt = be32_to_cpu(desc->bufcnt);
+ if (cmd & ETXD_B1V) {
+ len = (bufcnt & ETXD_B1CNT_MASK) >> ETXD_B1CNT_SHIFT;
+ dma_unmap_single(ip->dma_dev, be64_to_cpu(desc->p1),
+ len, DMA_TO_DEVICE);
+ }
+ if (cmd & ETXD_B2V) {
+ len = (bufcnt & ETXD_B2CNT_MASK) >> ETXD_B2CNT_SHIFT;
+ dma_unmap_single(ip->dma_dev, be64_to_cpu(desc->p2),
+ len, DMA_TO_DEVICE);
+ }
+}
+
static inline void ioc3_clean_tx_ring(struct ioc3_private *ip)
{
struct sk_buff *skb;
@@ -775,6 +823,7 @@ static inline void ioc3_clean_tx_ring(struct ioc3_private *ip)
for (i = 0; i < TX_RING_ENTRIES; i++) {
skb = ip->tx_skbs[i];
if (skb) {
+ ioc3_tx_unmap(ip, i);
ip->tx_skbs[i] = NULL;
dev_kfree_skb_any(skb);
}
@@ -794,8 +843,12 @@ static void ioc3_free_rx_bufs(struct ioc3_private *ip)

while (n_entry != rx_entry) {
skb = ip->rx_skbs[n_entry];
- if (skb)
+ if (skb) {
+ dma_unmap_single(ip->dma_dev,
+ be64_to_cpu(ip->rxr[n_entry]),
+ RX_BUF_SIZE, DMA_FROM_DEVICE);
dev_kfree_skb_any(skb);
+ }

n_entry = (n_entry + 1) & RX_RING_MASK;
}
@@ -805,6 +858,7 @@ static int ioc3_alloc_rx_bufs(struct net_device *dev)
{
struct ioc3_private *ip = netdev_priv(dev);
struct ioc3_erxbuf *rxb;
+ dma_addr_t d;
int i;

/* Now the rx buffers. The RX ring may be larger but
@@ -812,10 +866,10 @@ static int ioc3_alloc_rx_bufs(struct net_device *dev)
* this for performance and memory later.
*/
for (i = 0; i < RX_BUFFS; i++) {
- if (ioc3_alloc_skb(&ip->rx_skbs[i], &rxb))
+ if (ioc3_alloc_skb(ip, &ip->rx_skbs[i], &rxb, &d))
return -ENOMEM;

- ip->rxr[i] = cpu_to_be64(ioc3_map(rxb, 1));
+ ip->rxr[i] = cpu_to_be64(ioc3_map(d, PCI64_ATTR_BAR));
}
ip->rx_ci = 0;
ip->rx_pi = RX_BUFFS;
@@ -861,13 +915,7 @@ static void ioc3_init(struct net_device *dev)
readl(&regs->emcr);

/* Misc registers */
-#ifdef CONFIG_SGI_IP27
- /* Barrier on last store */
- writel(PCI64_ATTR_BAR >> 32, &regs->erbar);
-#else
- /* Let PCI API get it right */
- writel(0, &regs->erbar);
-#endif
+ writel(ERBAR_VAL, &regs->erbar);
readl(&regs->etcdc); /* Clear on read */
writel(15, &regs->ercsr); /* RX low watermark */
writel(0, &regs->ertr); /* Interrupt immediately */
@@ -883,13 +931,13 @@ static void ioc3_start(struct ioc3_private *ip)
unsigned long ring;

/* Now the rx ring base, consume & produce registers. */
- ring = ioc3_map(ip->rxr, 0);
+ ring = ioc3_map(ip->rxr_dma, PCI64_ATTR_PREC);
writel(ring >> 32, &regs->erbr_h);
writel(ring & 0xffffffff, &regs->erbr_l);
writel(ip->rx_ci << 3, &regs->ercir);
writel((ip->rx_pi << 3) | ERPIR_ARM, &regs->erpir);

- ring = ioc3_map(ip->txr, 0);
+ ring = ioc3_map(ip->txr_dma, PCI64_ATTR_PREC);

ip->txqlen = 0; /* nothing queued */

@@ -1163,6 +1211,7 @@ static int ioc3_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

ip = netdev_priv(dev);
ip->dev = dev;
+ ip->dma_dev = &pdev->dev;

dev->irq = pdev->irq;

@@ -1189,7 +1238,8 @@ static int ioc3_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
ioc3_stop(ip);

/* Allocate and rx ring. 4kb = 512 entries */
- ip->rxr = (unsigned long *)get_zeroed_page(GFP_ATOMIC);
+ ip->rxr = dma_direct_alloc_pages(ip->dma_dev, RX_RING_SIZE,
+ &ip->rxr_dma, GFP_ATOMIC, 0);
if (!ip->rxr) {
pr_err("ioc3-eth: rx ring allocation failed\n");
err = -ENOMEM;
@@ -1197,7 +1247,9 @@ static int ioc3_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
}

/* Allocate tx rings. 16kb = 128 bufs. */
- ip->txr = (struct ioc3_etxd *)__get_free_pages(GFP_KERNEL, 2);
+ ip->txr = dma_direct_alloc_pages(ip->dma_dev, TX_RING_SIZE,
+ &ip->txr_dma,
+ GFP_KERNEL | __GFP_ZERO, 0);
if (!ip->txr) {
pr_err("ioc3-eth: tx ring allocation failed\n");
err = -ENOMEM;
@@ -1256,8 +1308,12 @@ static int ioc3_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

out_stop:
del_timer_sync(&ip->ioc3_timer);
- kfree(ip->rxr);
- kfree(ip->txr);
+ if (ip->rxr)
+ dma_direct_free_pages(ip->dma_dev, RX_RING_SIZE, ip->rxr,
+ ip->rxr_dma, 0);
+ if (ip->txr)
+ dma_direct_free_pages(ip->dma_dev, TX_RING_SIZE, ip->txr,
+ ip->txr_dma, 0);
out_res:
pci_release_regions(pdev);
out_free:
@@ -1275,8 +1331,12 @@ static void ioc3_remove_one(struct pci_dev *pdev)
struct net_device *dev = pci_get_drvdata(pdev);
struct ioc3_private *ip = netdev_priv(dev);

- kfree(ip->rxr);
- kfree(ip->txr);
+ if (ip->rxr)
+ dma_direct_free_pages(ip->dma_dev, RX_RING_SIZE, ip->rxr,
+ ip->rxr_dma, 0);
+ if (ip->txr)
+ dma_direct_free_pages(ip->dma_dev, TX_RING_SIZE, ip->txr,
+ ip->txr_dma, 0);

unregister_netdev(dev);
del_timer_sync(&ip->ioc3_timer);
@@ -1382,18 +1442,32 @@ static netdev_tx_t ioc3_start_xmit(struct sk_buff *skb, struct net_device *dev)
unsigned long b2 = (data | 0x3fffUL) + 1UL;
unsigned long s1 = b2 - data;
unsigned long s2 = data + len - b2;
+ dma_addr_t d1, d2;

desc->cmd = cpu_to_be32(len | ETXD_INTWHENDONE |
ETXD_B1V | ETXD_B2V | w0);
desc->bufcnt = cpu_to_be32((s1 << ETXD_B1CNT_SHIFT) |
(s2 << ETXD_B2CNT_SHIFT));
- desc->p1 = cpu_to_be64(ioc3_map(skb->data, 1));
- desc->p2 = cpu_to_be64(ioc3_map((void *)b2, 1));
+ d1 = dma_map_single(ip->dma_dev, skb->data, s1, DMA_TO_DEVICE);
+ if (dma_mapping_error(ip->dma_dev, d1))
+ goto drop_packet;
+ d2 = dma_map_single(ip->dma_dev, (void *)b2, s1, DMA_TO_DEVICE);
+ if (dma_mapping_error(ip->dma_dev, d2)) {
+ dma_unmap_single(ip->dma_dev, d1, len, DMA_TO_DEVICE);
+ goto drop_packet;
+ }
+ desc->p1 = cpu_to_be64(ioc3_map(d1, PCI64_ATTR_PREF));
+ desc->p2 = cpu_to_be64(ioc3_map(d2, PCI64_ATTR_PREF));
} else {
+ dma_addr_t d;
+
/* Normal sized packet that doesn't cross a page boundary. */
desc->cmd = cpu_to_be32(len | ETXD_INTWHENDONE | ETXD_B1V | w0);
desc->bufcnt = cpu_to_be32(len << ETXD_B1CNT_SHIFT);
- desc->p1 = cpu_to_be64(ioc3_map(skb->data, 1));
+ d = dma_map_single(ip->dma_dev, skb->data, len, DMA_TO_DEVICE);
+ if (dma_mapping_error(ip->dma_dev, d))
+ goto drop_packet;
+ desc->p1 = cpu_to_be64(ioc3_map(d, PCI64_ATTR_PREF));
}

mb(); /* make sure all descriptor changes are visible */
@@ -1411,6 +1485,14 @@ static netdev_tx_t ioc3_start_xmit(struct sk_buff *skb, struct net_device *dev)
spin_unlock_irq(&ip->ioc3_lock);

return NETDEV_TX_OK;
+
+drop_packet:
+ dev_kfree_skb_any(skb);
+ dev->stats.tx_dropped++;
+
+ spin_unlock_irq(&ip->ioc3_lock);
+
+ return NETDEV_TX_OK;
}

static void ioc3_timeout(struct net_device *dev)
--
2.13.7