Commit 8b3d5a47 authored by Jakub Kicinski's avatar Jakub Kicinski Committed by David S. Miller

nfp: support long reads and writes with the cpp helpers

nfp_cpp_{read,write}() helpers perform device memory mapping (setting
the PCIe -> NOC translation BARs) and accessing it.  They, however,
currently implicitly expect that the length of entire operation will
fit in one BAR translation window.  There is a number of 16MB windows
available, and we don't really need to access such large areas today.

If the user, however, manages to trick the driver into making a big
mapping (e.g. by providing a huge fake FW file), the driver will
print a warning saying "No suitable BAR found for request" and a
stack trace - which most users find concerning.

To be future-proof and not scare users with warnings, make the
nfp_cpp_{read,write}() helpers do accesses chunk by chunk if the area
size is large.  Set the notion of "large" to 2MB, which is the size
of the smallest BAR window.
Signed-off-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 321b5e9a
......@@ -42,6 +42,7 @@
#include <linux/ctype.h>
#include <linux/types.h>
#include <linux/sizes.h>
#ifndef NFP_SUBSYS
#define NFP_SUBSYS "nfp"
......@@ -59,6 +60,8 @@
#define PCI_64BIT_BAR_COUNT 3
#define NFP_CPP_NUM_TARGETS 16
/* Max size of area it should be safe to request */
#define NFP_CPP_SAFE_AREA_SIZE SZ_2M
struct device;
......
......@@ -924,18 +924,9 @@ area_cache_put(struct nfp_cpp *cpp, struct nfp_cpp_area_cache *cache)
mutex_unlock(&cpp->area_cache_mutex);
}
/**
* nfp_cpp_read() - read from CPP target
* @cpp: CPP handle
* @destination: CPP id
* @address: offset into CPP target
* @kernel_vaddr: kernel buffer for result
* @length: number of bytes to read
*
* Return: length of io, or -ERRNO
*/
int nfp_cpp_read(struct nfp_cpp *cpp, u32 destination,
unsigned long long address, void *kernel_vaddr, size_t length)
static int __nfp_cpp_read(struct nfp_cpp *cpp, u32 destination,
unsigned long long address, void *kernel_vaddr,
size_t length)
{
struct nfp_cpp_area_cache *cache;
struct nfp_cpp_area *area;
......@@ -968,18 +959,43 @@ int nfp_cpp_read(struct nfp_cpp *cpp, u32 destination,
}
/**
* nfp_cpp_write() - write to CPP target
* nfp_cpp_read() - read from CPP target
* @cpp: CPP handle
* @destination: CPP id
* @address: offset into CPP target
* @kernel_vaddr: kernel buffer to read from
* @length: number of bytes to write
* @kernel_vaddr: kernel buffer for result
* @length: number of bytes to read
*
* Return: length of io, or -ERRNO
*/
int nfp_cpp_write(struct nfp_cpp *cpp, u32 destination,
unsigned long long address,
const void *kernel_vaddr, size_t length)
int nfp_cpp_read(struct nfp_cpp *cpp, u32 destination,
unsigned long long address, void *kernel_vaddr,
size_t length)
{
size_t n, offset;
int ret;
for (offset = 0; offset < length; offset += n) {
unsigned long long r_addr = address + offset;
/* make first read smaller to align to safe window */
n = min_t(size_t, length - offset,
ALIGN(r_addr + 1, NFP_CPP_SAFE_AREA_SIZE) - r_addr);
ret = __nfp_cpp_read(cpp, destination, address + offset,
kernel_vaddr + offset, n);
if (ret < 0)
return ret;
if (ret != n)
return offset + n;
}
return length;
}
static int __nfp_cpp_write(struct nfp_cpp *cpp, u32 destination,
unsigned long long address,
const void *kernel_vaddr, size_t length)
{
struct nfp_cpp_area_cache *cache;
struct nfp_cpp_area *area;
......@@ -1011,6 +1027,41 @@ int nfp_cpp_write(struct nfp_cpp *cpp, u32 destination,
return err;
}
/**
* nfp_cpp_write() - write to CPP target
* @cpp: CPP handle
* @destination: CPP id
* @address: offset into CPP target
* @kernel_vaddr: kernel buffer to read from
* @length: number of bytes to write
*
* Return: length of io, or -ERRNO
*/
int nfp_cpp_write(struct nfp_cpp *cpp, u32 destination,
unsigned long long address,
const void *kernel_vaddr, size_t length)
{
size_t n, offset;
int ret;
for (offset = 0; offset < length; offset += n) {
unsigned long long w_addr = address + offset;
/* make first write smaller to align to safe window */
n = min_t(size_t, length - offset,
ALIGN(w_addr + 1, NFP_CPP_SAFE_AREA_SIZE) - w_addr);
ret = __nfp_cpp_write(cpp, destination, address + offset,
kernel_vaddr + offset, n);
if (ret < 0)
return ret;
if (ret != n)
return offset + n;
}
return length;
}
/* Return the correct CPP address, and fixup xpb_addr as needed. */
static u32 nfp_xpb_to_cpp(struct nfp_cpp *cpp, u32 *xpb_addr)
{
......
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