From 3b724909a380fddb44dfa0072fc459c698a52658 Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Tue, 14 May 2024 10:20:54 -0700 Subject: [PATCH 0524/1625] drm/mipi-dsi: Reduce driver bloat of mipi_dsi_*_write_seq() Through a cooperative effort between Hsin-Yi Wang and Dmitry Baryshkov, we have realized the dev_err() in the mipi_dsi_*_write_seq() macros was causing quite a bit of bloat to the kernel. Let's hoist this call into drm_mipi_dsi.c by adding a "chatty" version of the functions that includes the print. While doing this, add a bit more comments to these macros making it clear that they print errors and also that they return out of _the caller's_ function. Without any changes to clients this gives a nice savings. Specifically the macro was inlined and thus the error report call was inlined into every call to mipi_dsi_dcs_write_seq() and mipi_dsi_generic_write_seq(). By using a call to a "chatty" function, the usage is reduced to one call in the chatty function and a function call at the invoking site. Building with my build system shows one example: $ scripts/bloat-o-meter \ .../before/panel-novatek-nt36672e.ko \ .../after/panel-novatek-nt36672e.ko add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-4404 (-4404) Function old new delta nt36672e_1080x2408_60hz_init 10640 6236 -4404 Total: Before=15055, After=10651, chg -29.25% Note that given the change in location of the print it's harder to include the "cmd" in the printout for mipi_dsi_dcs_write_seq() since, theoretically, someone could call the new chatty function with a zero-size array and it would be illegal to dereference data[0]. There's a printk format to print the whole buffer and this is probably more useful for debugging anyway. Given that we're doing this for mipi_dsi_dcs_write_seq(), let's also print the buffer for mipi_dsi_generic_write_seq() in the error case. It should be noted that the current consensus of DRM folks is that the mipi_dsi_*_write_seq() should be deprecated due to the non-intuitive return behavior. A future patch will formally mark them as deprecated and provide an alternative. Reviewed-by: Dmitry Baryshkov Reviewed-by: Neil Armstrong Reviewed-by: Linus Walleij Signed-off-by: Douglas Anderson Link: https://lore.kernel.org/r/20240514102056.v5.4.Id15fae80582bc74a0d4f1338987fa375738f45b9@changeid Signed-off-by: Neil Armstrong Link: https://patchwork.freedesktop.org/patch/msgid/20240514102056.v5.4.Id15fae80582bc74a0d4f1338987fa375738f45b9@changeid --- drivers/gpu/drm/drm_mipi_dsi.c | 56 ++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c index 795001bb7ff1..4d2685d5a6e0 100644 --- a/drivers/gpu/drm/drm_mipi_dsi.c +++ b/drivers/gpu/drm/drm_mipi_dsi.c @@ -764,6 +764,34 @@ ssize_t mipi_dsi_generic_write(struct mipi_dsi_device *dsi, const void *payload, } EXPORT_SYMBOL(mipi_dsi_generic_write); +/** + * mipi_dsi_generic_write_chatty() - mipi_dsi_generic_write() w/ an error log + * @dsi: DSI peripheral device + * @payload: buffer containing the payload + * @size: size of payload buffer + * + * Like mipi_dsi_generic_write() but includes a dev_err() + * call for you and returns 0 upon success, not the number of bytes sent. + * + * Return: 0 on success or a negative error code on failure. + */ +int mipi_dsi_generic_write_chatty(struct mipi_dsi_device *dsi, + const void *payload, size_t size) +{ + struct device *dev = &dsi->dev; + ssize_t ret; + + ret = mipi_dsi_generic_write(dsi, payload, size); + if (ret < 0) { + dev_err(dev, "sending generic data %*ph failed: %zd\n", + (int)size, payload, ret); + return ret; + } + + return 0; +} +EXPORT_SYMBOL(mipi_dsi_generic_write_chatty); + /** * mipi_dsi_generic_read() - receive data using a generic read packet * @dsi: DSI peripheral device @@ -852,6 +880,34 @@ ssize_t mipi_dsi_dcs_write_buffer(struct mipi_dsi_device *dsi, } EXPORT_SYMBOL(mipi_dsi_dcs_write_buffer); +/** + * mipi_dsi_dcs_write_buffer_chatty - mipi_dsi_dcs_write_buffer() w/ an error log + * @dsi: DSI peripheral device + * @data: buffer containing data to be transmitted + * @len: size of transmission buffer + * + * Like mipi_dsi_dcs_write_buffer() but includes a dev_err() + * call for you and returns 0 upon success, not the number of bytes sent. + * + * Return: 0 on success or a negative error code on failure. + */ +int mipi_dsi_dcs_write_buffer_chatty(struct mipi_dsi_device *dsi, + const void *data, size_t len) +{ + struct device *dev = &dsi->dev; + ssize_t ret; + + ret = mipi_dsi_dcs_write_buffer(dsi, data, len); + if (ret < 0) { + dev_err(dev, "sending dcs data %*ph failed: %zd\n", + (int)len, data, ret); + return ret; + } + + return 0; +} +EXPORT_SYMBOL(mipi_dsi_dcs_write_buffer_chatty); + /** * mipi_dsi_dcs_write() - send DCS write command * @dsi: DSI peripheral device -- 2.52.0