[PATCH v5 2/7] net: macb: Add DMA 64-bit address support for macb

Padmarao Begari padmarao.b at gmail.com
Fri Dec 11 12:56:30 CET 2020


Hi Bin,

On Fri, Dec 11, 2020 at 2:59 PM Bin Meng <bmeng.cn at gmail.com> wrote:

> Hi Padmarao,
>
> On Fri, Dec 11, 2020 at 4:49 PM Padmarao Begari <padmarao.b at gmail.com>
> wrote:
> >
> > Hi Bin,
> >
> > On Thu, Dec 10, 2020 at 4:08 PM Bin Meng <bmeng.cn at gmail.com> wrote:
> >>
> >> Hi Padmarao,
> >>
> >> On Thu, Dec 10, 2020 at 6:33 PM Bin Meng <bmeng.cn at gmail.com> wrote:
> >> >
> >> > Hi Padmarao,
> >> >
> >> > On Thu, Dec 3, 2020 at 4:44 AM Padmarao Begari
> >> > <padmarao.begari at microchip.com> wrote:
> >> > >
> >> > > Enable 32-bit or 64-bit DMA in the macb driver based on the macb
> >> > > compatible string of the device tree node.
> >> > >
> >> > > Signed-off-by: Padmarao Begari <padmarao.begari at microchip.com>
> >> > > Reviewed-by: Anup Patel <anup.patel at wdc.com>
> >> > > ---
> >> > >  drivers/net/macb.c | 131
> +++++++++++++++++++++++++++++++++++++++------
> >> > >  drivers/net/macb.h |   6 +++
> >> > >  2 files changed, 120 insertions(+), 17 deletions(-)
> >> > >
> >> > > diff --git a/drivers/net/macb.c b/drivers/net/macb.c
> >> > > index b80a259ff7..e7c93d4747 100644
> >> > > --- a/drivers/net/macb.c
> >> > > +++ b/drivers/net/macb.c
> >> > > @@ -83,7 +83,16 @@ struct macb_dma_desc {
> >> > >         u32     ctrl;
> >> > >  };
> >> > >
> >> > > -#define DMA_DESC_BYTES(n)      (n * sizeof(struct macb_dma_desc))
> >> > > +struct macb_dma_desc_64 {
> >> > > +       u32 addrh;
> >> > > +       u32 unused;
> >> > > +};
> >> > > +
> >> > > +#define HW_DMA_CAP_32B         0
> >> > > +#define HW_DMA_CAP_64B         1
> >> > > +
> >> > > +#define DMA_DESC_SIZE          16
> >> > > +#define DMA_DESC_BYTES(n)      ((n) * DMA_DESC_SIZE)
> >> > >  #define MACB_TX_DMA_DESC_SIZE  (DMA_DESC_BYTES(MACB_TX_RING_SIZE))
> >> > >  #define MACB_RX_DMA_DESC_SIZE  (DMA_DESC_BYTES(MACB_RX_RING_SIZE))
> >> > >  #define MACB_TX_DUMMY_DMA_DESC_SIZE    (DMA_DESC_BYTES(1))
> >> > > @@ -133,6 +142,7 @@ struct macb_device {
> >> > >  #endif
> >> > >         phy_interface_t         phy_interface;
> >> > >  #endif
> >> > > +       unsigned short          hw_dma_cap;
> >> > >  };
> >> > >
> >> > >  struct macb_config {
> >> > > @@ -307,6 +317,24 @@ static inline void
> macb_invalidate_rx_buffer(struct macb_device *macb)
> >> > >
> >> > >  #if defined(CONFIG_CMD_NET)
> >> > >
> >> > > +static struct macb_dma_desc_64 *macb_64b_desc(struct macb_dma_desc
> *desc)
> >> > > +{
> >> > > +       return (struct macb_dma_desc_64 *)((void *)desc
> >> > > +               + sizeof(struct macb_dma_desc));
> >> > > +}
> >> > > +
> >> > > +static void macb_set_addr(struct macb_device *macb, struct
> macb_dma_desc *desc,
> >> > > +                         ulong addr)
> >> > > +{
> >> > > +       struct macb_dma_desc_64 *desc_64;
> >> > > +
> >> > > +       if (macb->hw_dma_cap & HW_DMA_CAP_64B) {
> >> > > +               desc_64 = macb_64b_desc(desc);
> >> > > +               desc_64->addrh = upper_32_bits(addr);
> >> > > +       }
> >> > > +       desc->addr = lower_32_bits(addr);
> >> > > +}
> >> > > +
> >> > >  static int _macb_send(struct macb_device *macb, const char *name,
> void *packet,
> >> > >                       int length)
> >> > >  {
> >> > > @@ -325,8 +353,12 @@ static int _macb_send(struct macb_device
> *macb, const char *name, void *packet,
> >> > >                 macb->tx_head++;
> >> > >         }
> >> > >
> >> > > +       if (macb->hw_dma_cap & HW_DMA_CAP_64B)
> >> > > +               tx_head = tx_head * 2;
> >> > > +
> >> > >         macb->tx_ring[tx_head].ctrl = ctrl;
> >> > > -       macb->tx_ring[tx_head].addr = paddr;
> >> > > +       macb_set_addr(macb, &macb->tx_ring[tx_head], paddr);
> >> > > +
> >> > >         barrier();
> >> > >         macb_flush_ring_desc(macb, TX);
> >> > >         macb_writel(macb, NCR, MACB_BIT(TE) | MACB_BIT(RE) |
> MACB_BIT(TSTART));
> >> > > @@ -363,19 +395,28 @@ static void reclaim_rx_buffers(struct
> macb_device *macb,
> >> > >                                unsigned int new_tail)
> >> > >  {
> >> > >         unsigned int i;
> >> > > +       unsigned int count;
> >> > >
> >> > >         i = macb->rx_tail;
> >> > >
> >> > >         macb_invalidate_ring_desc(macb, RX);
> >> > >         while (i > new_tail) {
> >> > > -               macb->rx_ring[i].addr &= ~MACB_BIT(RX_USED);
> >> > > +               if (macb->hw_dma_cap & HW_DMA_CAP_64B)
> >> > > +                       count = i * 2;
> >> > > +               else
> >> > > +                       count = i;
> >> > > +               macb->rx_ring[count].addr &= ~MACB_BIT(RX_USED);
> >> > >                 i++;
> >> > >                 if (i > MACB_RX_RING_SIZE)
> >> > >                         i = 0;
> >> > >         }
> >> > >
> >> > >         while (i < new_tail) {
> >> > > -               macb->rx_ring[i].addr &= ~MACB_BIT(RX_USED);
> >> > > +               if (macb->hw_dma_cap & HW_DMA_CAP_64B)
> >> > > +                       count = i * 2;
> >> > > +               else
> >> > > +                       count = i;
> >> > > +               macb->rx_ring[count].addr &= ~MACB_BIT(RX_USED);
> >> > >                 i++;
> >> > >         }
> >> > >
> >> > > @@ -390,16 +431,25 @@ static int _macb_recv(struct macb_device
> *macb, uchar **packetp)
> >> > >         void *buffer;
> >> > >         int length;
> >> > >         u32 status;
> >> > > +       u8 flag = false;
> >> > >
> >> > >         macb->wrapped = false;
> >> > >         for (;;) {
> >> > >                 macb_invalidate_ring_desc(macb, RX);
> >> > >
> >> > > +               if (macb->hw_dma_cap & HW_DMA_CAP_64B)
> >> > > +                       next_rx_tail = next_rx_tail * 2;
> >> > > +
> >> > >                 if (!(macb->rx_ring[next_rx_tail].addr &
> MACB_BIT(RX_USED)))
> >> > >                         return -EAGAIN;
> >> > >
> >> > >                 status = macb->rx_ring[next_rx_tail].ctrl;
> >> > >                 if (status & MACB_BIT(RX_SOF)) {
> >> > > +                       if (macb->hw_dma_cap & HW_DMA_CAP_64B) {
> >> > > +                               next_rx_tail = next_rx_tail / 2;
> >> > > +                               flag = true;
> >> > > +                       }
> >> > > +
> >> > >                         if (next_rx_tail != macb->rx_tail)
> >> > >                                 reclaim_rx_buffers(macb,
> next_rx_tail);
> >> > >                         macb->wrapped = false;
> >> > > @@ -426,11 +476,22 @@ static int _macb_recv(struct macb_device
> *macb, uchar **packetp)
> >> > >                                 *packetp = buffer;
> >> > >                         }
> >> > >
> >> > > +                       if (macb->hw_dma_cap & HW_DMA_CAP_64B) {
> >> > > +                               if (!flag)
> >> > > +                                       next_rx_tail = next_rx_tail
> / 2;
> >> > > +                       }
> >> > > +
> >> > >                         if (++next_rx_tail >= MACB_RX_RING_SIZE)
> >> > >                                 next_rx_tail = 0;
> >> > >                         macb->next_rx_tail = next_rx_tail;
> >> > >                         return length;
> >> > >                 } else {
> >> > > +                       if (macb->hw_dma_cap & HW_DMA_CAP_64B) {
> >> > > +                               if (!flag)
> >> > > +                                       next_rx_tail = next_rx_tail
> / 2;
> >> > > +                               flag = false;
> >> > > +                       }
> >> > > +
> >> > >                         if (++next_rx_tail >= MACB_RX_RING_SIZE) {
> >> > >                                 macb->wrapped = true;
> >> > >                                 next_rx_tail = 0;
> >> > > @@ -718,6 +779,7 @@ static int gmac_init_multi_queues(struct
> macb_device *macb)
> >> > >  {
> >> > >         int i, num_queues = 1;
> >> > >         u32 queue_mask;
> >> > > +       unsigned long paddr;
> >> > >
> >> > >         /* bit 0 is never set but queue 0 always exists */
> >> > >         queue_mask = gem_readl(macb, DCFG6) & 0xff;
> >> > > @@ -731,10 +793,18 @@ static int gmac_init_multi_queues(struct
> macb_device *macb)
> >> > >         macb->dummy_desc->addr = 0;
> >> > >         flush_dcache_range(macb->dummy_desc_dma,
> macb->dummy_desc_dma +
> >> > >                         ALIGN(MACB_TX_DUMMY_DMA_DESC_SIZE,
> PKTALIGN));
> >> > > -
> >> > > -       for (i = 1; i < num_queues; i++)
> >> > > -               gem_writel_queue_TBQP(macb, macb->dummy_desc_dma, i
> - 1);
> >> > > -
> >> > > +       paddr = macb->dummy_desc_dma;
> >> > > +
> >> > > +       for (i = 1; i < num_queues; i++) {
> >> > > +               gem_writel_queue_TBQP(macb, lower_32_bits(paddr), i
> - 1);
> >> > > +               gem_writel_queue_RBQP(macb, lower_32_bits(paddr), i
> - 1);
> >> > > +               if (macb->hw_dma_cap & HW_DMA_CAP_64B) {
> >> > > +                       gem_writel_queue_TBQPH(macb,
> upper_32_bits(paddr),
> >> > > +                                              i - 1);
> >> > > +                       gem_writel_queue_RBQPH(macb,
> upper_32_bits(paddr),
> >> > > +                                              i - 1);
> >> > > +               }
> >> > > +       }
> >> > >         return 0;
> >> > >  }
> >> > >
> >> > > @@ -760,6 +830,9 @@ static void gmac_configure_dma(struct
> macb_device *macb)
> >> > >                 dmacfg &= ~GEM_BIT(ENDIA_DESC);
> >> > >
> >> > >         dmacfg &= ~GEM_BIT(ADDR64);
> >> > > +       if (macb->hw_dma_cap & HW_DMA_CAP_64B)
> >> > > +               dmacfg |= GEM_BIT(ADDR64);
> >>
> >> Does GEM on PolarFire not support 32-bit DMA address? I believe in
> >> U-Boot we can only get 32-bit address.
> >>
> >
> > Yes, it's not work when I tested with 32-bit DMA.
>
> Okay, then this explains why 64-bit DMA patch is needed. Is this a bug
> of the GEM IP integrated in the PolarFire?
> Could you please write something in the commit message to clarify?
> That would be helpful. Thanks!


No, it's not a bug, The PolarFire SoC Memory Protection Unit(MPU) gives the
64-bit DMA access with GEM, the MPU transactions on the AXI bus is 64-bit
not 32-bit.

Regards
Padmarao




> Regards,
> Bin
>


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