Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

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

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

drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cpp.h

+3 −0
Original line number Diff line number Diff line
@@ -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;

drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c

+69 −18
Original line number Diff line number Diff line
@@ -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;
@@ -968,16 +959,41 @@ 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,

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)

{
@@ -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)

{