[PATCH net-next 4/4] net: ipa: relax 64-bit build requirement
From: Alex Elder <hidden>
Date: 2021-03-17 22:30:48
Also in:
lkml
Subsystem:
networking drivers, qcom ipa driver, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Alex Elder, Linus Torvalds
We currently assume the IPA driver is built only for a 64 bit kernel. When this constraint was put in place it eliminated some do_div() calls, replacing them with the "/" and "%" operators. We now only use these operations on u32 and size_t objects. In a 32-bit kernel build, size_t will be 32 bits wide, so there remains no reason to use do_div() for divide and modulo. A few recent commits also fix some code that assumes that DMA addresses are 64 bits wide. With that, we can get rid of the 64-bit build requirement. Signed-off-by: Alex Elder <redacted> --- drivers/net/ipa/Kconfig | 2 +- drivers/net/ipa/ipa_main.c | 10 ++++++++-- 2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ipa/Kconfig b/drivers/net/ipa/Kconfig
index b68f1289b89ef..90a90262e0d07 100644
--- a/drivers/net/ipa/Kconfig
+++ b/drivers/net/ipa/Kconfig@@ -1,6 +1,6 @@ config QCOM_IPA tristate "Qualcomm IPA support" - depends on 64BIT && NET && QCOM_SMEM + depends on NET && QCOM_SMEM depends on ARCH_QCOM || COMPILE_TEST depends on QCOM_RPROC_COMMON || (QCOM_RPROC_COMMON=n && COMPILE_TEST) select QCOM_MDT_LOADER if ARCH_QCOM
diff --git a/drivers/net/ipa/ipa_main.c b/drivers/net/ipa/ipa_main.c
index 97c1b55405cbf..d354e3e65ec50 100644
--- a/drivers/net/ipa/ipa_main.c
+++ b/drivers/net/ipa/ipa_main.c@@ -735,8 +735,14 @@ MODULE_DEVICE_TABLE(of, ipa_match); static void ipa_validate_build(void) { #ifdef IPA_VALIDATE - /* We assume we're working on 64-bit hardware */ - BUILD_BUG_ON(!IS_ENABLED(CONFIG_64BIT)); + /* At one time we assumed a 64-bit build, allowing some do_div() + * calls to be replaced by simple division or modulo operations. + * We currently only perform divide and modulo operations on u32, + * u16, or size_t objects, and of those only size_t has any chance + * of being a 64-bit value. (It should be guaranteed 32 bits wide + * on a 32-bit build, but there is no harm in verifying that.) + */ + BUILD_BUG_ON(!IS_ENABLED(CONFIG_64BIT) && sizeof(size_t) != 4); /* Code assumes the EE ID for the AP is 0 (zeroed structure field) */ BUILD_BUG_ON(GSI_EE_AP != 0);
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2.27.0