[PATCH v3 1/7] linux/log2.h: Add roundup/rounddown_pow_two64() family of functions

Nicolas Saenz Julienne
2019-11-26T09:21:06Z

Some users need to make sure their rounding function accepts and returns
64bit long variables regardless of the architecture. Sadly
roundup/rounddown_pow_two() takes and returns unsigned longs. Create a
new generic 64bit variant of the function and cleanup rougue custom
implementations.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>

---

Changes since v2:
- Use u64
- Rename function to roundup/down_pow_two_u64()
- Use 1ULL instead of 1UL
- Include function usage in of/device.c and acpi/arm64/iort.c

drivers/acpi/arm64/iort.c | 2 +-
drivers/net/ethernet/mellanox/mlx4/en_clock.c | 3 +-
drivers/of/device.c | 2 +-
.../pci/controller/cadence/pcie-cadence-ep.c | 7 +--
drivers/pci/controller/cadence/pcie-cadence.c | 7 +--
drivers/pci/controller/pcie-rockchip-ep.c | 9 ++--
include/linux/log2.h | 52 +++++++++++++++++++
kernel/dma/direct.c | 3 +-
8 files changed, 65 insertions(+), 20 deletions(-)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 33f71983e001..4809d3757d71 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -1090,7 +1090,7 @@ void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
* firmware.
*/
end = dmaaddr + size - 1;
- mask = DMA_BIT_MASK(ilog2(end) + 1);
+ mask = roundup_pow_of_two_u64(end) - 1;
dev->bus_dma_limit = end;
dev->coherent_dma_mask = mask;
*dev->dma_mask = mask;
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
index 024788549c25..ba5368e221f3 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
@@ -33,6 +33,7 @@

#include <linux/mlx4/device.h>
#include <linux/clocksource.h>
+#include <linux/log2.h>

#include "mlx4_en.h"

@@ -252,7 +253,7 @@ static u32 freq_to_shift(u16 freq)
{
u32 freq_khz = freq * 1000;
u64 max_val_cycles = freq_khz * 1000 * MLX4_EN_WRAP_AROUND_SEC;
- u64 max_val_cycles_rounded = 1ULL << fls64(max_val_cycles - 1);
+ u64 max_val_cycles_rounded = roundup_pow_of_two_u64(max_val_cycles);
/* calculate max possible multiplier in order to fit in 64bit */
u64 max_mul = div64_u64(ULLONG_MAX, max_val_cycles_rounded);

diff --git a/drivers/of/device.c b/drivers/of/device.c
index e9127db7b067..418d7d014af1 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -149,7 +149,7 @@ int of_dma_configure(struct device *dev, struct device_node *np, bool force_dma)
* set by the driver.
*/
end = dma_addr + size - 1;
- mask = DMA_BIT_MASK(ilog2(end) + 1);
+ mask = roundup_pow_of_two_u64(end) - 1;
dev->coherent_dma_mask &= mask;
*dev->dma_mask &= mask;
/* ...but only set bus limit if we found valid dma-ranges earlier */
diff --git a/drivers/pci/controller/cadence/pcie-cadence-ep.c b/drivers/pci/controller/cadence/pcie-cadence-ep.c
index 1c173dad67d1..f6e37eb67c68 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-ep.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c
@@ -10,6 +10,7 @@
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/sizes.h>
+#include <linux/log2.h>

#include "pcie-cadence.h"

@@ -61,11 +62,7 @@ static int cdns_pcie_ep_set_bar(struct pci_epc *epc, u8 fn,

/* BAR size is 2^(aperture + 7) */
sz = max_t(size_t, epf_bar->size, CDNS_PCIE_EP_MIN_APERTURE);
- /*
- * roundup_pow_of_two() returns an unsigned long, which is not suited
- * for 64bit values.
- */
- sz = 1ULL << fls64(sz - 1);
+ sz = roundup_pow_of_two_u64(sz);
aperture = ilog2(sz) - 7; /* 128B -> 0, 256B -> 1, 512B -> 2, ... */

if ((flags & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {
diff --git a/drivers/pci/controller/cadence/pcie-cadence.c b/drivers/pci/controller/cadence/pcie-cadence.c
index cd795f6fc1e2..2ddda5ac60c4 100644
--- a/drivers/pci/controller/cadence/pcie-cadence.c
+++ b/drivers/pci/controller/cadence/pcie-cadence.c
@@ -4,6 +4,7 @@
// Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>

#include <linux/kernel.h>
+#include <linux/log2.h>

#include "pcie-cadence.h"

@@ -11,11 +12,7 @@ void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u8 fn,
u32 r, bool is_io,
u64 cpu_addr, u64 pci_addr, size_t size)
{
- /*
- * roundup_pow_of_two() returns an unsigned long, which is not suited
- * for 64bit values.
- */
- u64 sz = 1ULL << fls64(size - 1);
+ u64 sz = roundup_pow_of_two_u64(size);
int nbits = ilog2(sz);
u32 addr0, addr1, desc0, desc1;

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index d743b0a48988..343f9683b540 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -16,6 +16,7 @@
#include <linux/platform_device.h>
#include <linux/pci-epf.h>
#include <linux/sizes.h>
+#include <linux/log2.h>

#include "pcie-rockchip.h"

@@ -70,7 +71,7 @@ static void rockchip_pcie_prog_ep_ob_atu(struct rockchip_pcie *rockchip, u8 fn,
u32 r, u32 type, u64 cpu_addr,
u64 pci_addr, size_t size)
{
- u64 sz = 1ULL << fls64(size - 1);
+ u64 sz = roundup_pow_of_two_u64(size);
int num_pass_bits = ilog2(sz);
u32 addr0, addr1, desc0, desc1;
bool is_nor_msg = (type == AXI_WRAPPER_NOR_MSG);
@@ -172,11 +173,7 @@ static int rockchip_pcie_ep_set_bar(struct pci_epc *epc, u8 fn,
/* BAR size is 2^(aperture + 7) */
sz = max_t(size_t, epf_bar->size, MIN_EP_APERTURE);

- /*
- * roundup_pow_of_two() returns an unsigned long, which is not suited
- * for 64bit values.
- */
- sz = 1ULL << fls64(sz - 1);
+ sz = roundup_pow_of_two_u64(sz);
aperture = ilog2(sz) - 7; /* 128B -> 0, 256B -> 1, 512B -> 2, ... */

if ((flags & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {
diff --git a/include/linux/log2.h b/include/linux/log2.h
index 83a4a3ca3e8a..0db47b78faa2 100644
--- a/include/linux/log2.h
+++ b/include/linux/log2.h
@@ -67,6 +67,24 @@ unsigned long __rounddown_pow_of_two(unsigned long n)
return 1UL << (fls_long(n) - 1);
}

+/**
+ * __roundup_pow_of_two_u64() - round 64bit value up to nearest power of two
+ * @n: value to round up
+ */
+static inline __attribute__((const)) u64 __roundup_pow_of_two_u64(u64 n)
+{
+ return 1ULL << fls64(n - 1);
+}
+
+/**
+ * __rounddown_pow_of_two_u64() - round 64bit value down to nearest power of two
+ * @n: value to round down
+ */
+static inline __attribute__((const)) u64 __rounddown_pow_of_two_u64(u64 n)
+{
+ return 1ULL << (fls64(n) - 1);
+}
+
/**
* const_ilog2 - log base 2 of 32-bit or a 64-bit constant unsigned value
* @n: parameter
@@ -194,6 +212,40 @@ unsigned long __rounddown_pow_of_two(unsigned long n)
__rounddown_pow_of_two(n) \
)

+/**
+ * roundup_pow_of_two_u64 - round the given 64bit value up to nearest power of
+ * two
+ * @n: parameter
+ *
+ * round the given value up to the nearest power of two
+ * - the result is undefined when n == 0
+ * - this can be used to initialise global variables from constant data
+ */
+#define roundup_pow_of_two_u64(n) \
+( \
+ __builtin_constant_p(n) ? ( \
+ (n == 1) ? 1 : \
+ (1UL << (ilog2((n) - 1) + 1)) \
+ ) : \
+ __roundup_pow_of_two_u64(n) \
+)
+
+/**
+ * rounddown_pow_of_two_u64 - round the given 64bit value down to nearest power
+ * of two
+ * @n: parameter
+ *
+ * round the given value down to the nearest power of two
+ * - the result is undefined when n == 0
+ * - this can be used to initialise global variables from constant data
+ */
+#define rounddown_pow_of_two_u64(n) \
+( \
+ __builtin_constant_p(n) ? ( \
+ (1UL << ilog2(n))) : \
+ __rounddown_pow_of_two_u64(n) \
+)
+
static inline __attribute_const__
int __order_base_2(unsigned long n)
{
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 6af7ae83c4ad..8dd59e51b4dc 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -15,6 +15,7 @@
#include <linux/vmalloc.h>
#include <linux/set_memory.h>
#include <linux/swiotlb.h>
+#include <linux/log2.h>

/*
* Most architectures use ZONE_DMA for the first 16 Megabytes, but some use it
@@ -53,7 +54,7 @@ u64 dma_direct_get_required_mask(struct device *dev)
{
u64 max_dma = phys_to_dma_direct(dev, (max_pfn - 1) << PAGE_SHIFT);

- return (1ULL << (fls64(max_dma) - 1)) * 2 - 1;
+ return rounddown_pow_of_two_u64(max_dma) * 2 - 1;
}

static gfp_t __dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
--
2.24.0