On 01/03/2018 19:11, Andy Shevchenko wrote:
On Tue, 2018-02-27 at 00:40 +0800, John Garry wrote:
From: Zhichang Yuan <yuanzhichang@xxxxxxxxxxxxx>
In commit 41f8bba7f555 ("of/pci: Add pci_register_io_range() and
pci_pio_to_address()"), a new I/O space management was supported. With
that driver, the I/O ranges configured for PCI/PCIe hosts on some
architectures can be mapped to logical PIO, converted easily between
CPU address and the corresponding logicial PIO. Based on this, PCI
I/O devices can be accessed in a memory read/write way through the
unified in/out accessors.
But on some archs/platforms, there are bus hosts which access I/O
peripherals with host-local I/O port addresses rather than memory
addresses after memory-mapped.
To support those devices, a more generic I/O mapping method is
introduced
here. Through this patch, both the CPU addresses and the host-local
port
can be mapped into the logical PIO space with different logical/fake
PIOs.
After this, all the I/O accesses to either PCI MMIO devices or host-
local
I/O peripherals can be unified into the existing I/O accessors defined
in
asm-generic/io.h and be redirected to the right device-specific hooks
based on the input logical PIO.
A bit more small comments.
Hi Andy,
+#ifndef __LINUX_LOGIC_PIO_H
+#define __LINUX_LOGIC_PIO_H
+
+#ifdef __KERNEL__
Hmm... How the header in include/linux/ can be non-kernel?
I did doubt the legitimacy of this. I think it should be ok to remove.
+ list_for_each_entry_rcu(range, &io_range_list, list) {
+ if (range->flags == LOGIC_PIO_CPU_MMIO &&
+ new_range->flags ==
LOGIC_PIO_CPU_MMIO) {
It's rather fancy indentation.
Right, I should align these.
+ if (start >= range->hw_start + range->size ||
+ end < range->hw_start)
Misses {}
Right, I will fix.
+ allocated_mmio_size += range->size;
+ else {
+ ret = -EFAULT;
+ goto end_register;
+ }
+ if (allocated_mmio_size + new_range->size - 1 >
+ MMIO_UPPER_LIMIT) {
Fancy indentation.
+ if (allocated_mmio_size + SZ_64K - 1 >
+ MMIO_UPPER_LIMIT) {
Ditto.
Will fix both
+ if (allocated_iio_size + new_range->size - 1 >
+ IO_SPACE_LIMIT) {
While this is nothing wrong, like above I would consider to check how
long it is and consider putting on one line.
Fine. Some symbol names can be shortened to aid this.
+/**
+ * logic_pio_to_hwaddr - translate logical PIO to HW address
+ * @pio: logical PIO value
+ *
+ * Returns HW address if valid, -1 otherwise
It can't return -1 when the return type is unsigned.
+ *
+ * Translate the input logical pio to the corresponding hardware
address.
+ * The input pio should be unique in the whole logical PIO space.
+ */
+resource_size_t logic_pio_to_hwaddr(unsigned long pio)
+{
+ struct logic_pio_hwaddr *range;
+ resource_size_t hwaddr = (resource_size_t)-1;
Ditto.
ok, I should have changed this to ~0 also.
+ return hwaddr;
+}
+ list_for_each_entry_rcu(range, &io_range_list, list) {
+ if (range->flags != LOGIC_PIO_CPU_MMIO)
+ continue;
+ if (addr >= range->hw_start &&
+ addr < range->hw_start + range->size)
Perhaps you may copy'n'paste in_range() macro from fs/ext* files and use
in this module. At some point it would be good to make it generic.
OK, I should be able to copy. It would not be good to include
fs/ufs/util.h, but a generic helper would be useful.
+ return addr - range->hw_start +
+ range->io_start;
+ }
Thanks very much,
John
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