mbox series

[v2,0/5] arm: aspeed: Add UART DMA support

Message ID 20230314021817.30446-1-chiawei_wang@aspeedtech.com
Headers
Series arm: aspeed: Add UART DMA support |

Message

ChiaWei Wang March 14, 2023, 2:18 a.m. UTC 
  This patch serias adds the 8250 driver with DMA support for AST26xx UART devices

v2 change:
 - re-write UDMA driver based on the DMAEngine framework
 - re-write 8250_aspeed driver with DMA support based on the 8250_dma implementation
 - remove virtual UART part as there is already a 8250_aspeed_vuart driver

Chia-Wei Wang (5):
  dt-bindings: serial: 8250: Add aspeed,ast2600-uart
  dt-bindings: dmaengine: Add AST2600 UDMA bindings
  dmaengine: aspeed: Add AST2600 UART DMA driver
  serial: 8250: Add AST2600 UART driver
  ARM: dts: aspeed-g6: Add UDMA node

 .../bindings/dma/aspeed,ast2600-udma.yaml     |  56 ++
 .../devicetree/bindings/serial/8250.yaml      |   1 +
 arch/arm/boot/dts/aspeed-g6.dtsi              |   9 +
 drivers/dma/Kconfig                           |   9 +
 drivers/dma/Makefile                          |   1 +
 drivers/dma/ast2600-udma.c                    | 528 ++++++++++++++++++
 drivers/tty/serial/8250/8250_aspeed.c         | 224 ++++++++
 drivers/tty/serial/8250/Kconfig               |   8 +
 drivers/tty/serial/8250/Makefile              |   1 +
 include/dt-bindings/dma/ast2600-udma.h        |  40 ++
 10 files changed, 877 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/aspeed,ast2600-udma.yaml
 create mode 100644 drivers/dma/ast2600-udma.c
 create mode 100644 drivers/tty/serial/8250/8250_aspeed.c
 create mode 100644 include/dt-bindings/dma/ast2600-udma.h

Comments

ChiaWei Wang March 20, 2023, 2:54 a.m. UTC | #1 
> From: Hillf Danton <hdanton@sina.com>
> Sent: Saturday, March 18, 2023 11:01 AM
> 
> On 14 Mar 2023 10:18:15 +0800 Chia-Wei Wang
> <chiawei_wang@aspeedtech.com>
> > +static irqreturn_t ast2600_udma_isr(int irq, void *arg) {
> 
> [...]
> 
> > +	/* handle RX interrupt */
> > +	sts = readl(udma->regs + UDMA_RX_INT_STS);
> > +	for_each_set_bit(ch_bit, (unsigned long *)&sts, udma->n_ucs / 2) {
> > +		ch_id = (ch_bit << 1) + 1;
> > +		wptr = readl(udma->regs + UDMA_CH_WPTR(ch_id));
> > +
> > +		uc = &udma->ucs[ch_id];
> > +		ud = &uc->ud;
> > +		tx = &ud->tx;
> > +
> > +		uc->residue = (ud->size & ~UDMA_CH_CTRL_BUFSZ) - wptr;
> > +
> > +		/* handle non-4B-aligned case */
> > +		if (ud->addr & 0x3) {
> > +			p = phys_to_virt(dma_to_phys(uc->chan.device->dev,
> ud->addr));
> 
> This does not work if the dma address has no corresponding struct page.

Will add the error check for dma_to_phys to prevent further unexpected memory accesses.

Thanks,
Chiawei

> 
> > +			memcpy(p, uc->buf, wptr);
> > +		}
> > +
> > +		ast2600_udma_terminate(&uc->chan);
> > +
> > +		dma_cookie_complete(tx);
> > +		dma_descriptor_unmap(tx);
> > +		dmaengine_desc_get_callback_invoke(tx, NULL);
> > +	}
> > +
> > +	return IRQ_HANDLED;
> > +}