How to send custom size payload in PCIe TLP?

In my PCIe driver, after pci_ioremap_bar() to map BARs to memory spaces, I can use:

    unsigned int ioread8(void __iomem *addr);
    unsigned int ioread16(void __iomem *addr);
    unsigned int ioread32(void __iomem *addr);
    void iowrite8(u8 value, void __iomem *addr);
    void iowrite16(u16 value, void __iomem *addr);
    void iowrite32(u32 value, void __iomem *addr);

• Each call generates a single MRd/MWr TLP with a maximum payload of 4B/32b.

• My PCIe device supports TLP payload up to 1024 Bytes.

How can I take advantage of that and being able to send more bytes in a single TLP from CPU to my device?

My question puts aside the DMA. Simply PIO from the host/CPU. From my device, I can send 1KB TLP to dma_alloc_coherent() memory without any problem. I'd like to do the same way without using descriptors.

I know it isn't possible, but I read somewhere recent CPUs might have new features that would allow me to send more than one DWORD.