From 7df898b1a70b13c3a8892625f4ead929d9554293 Mon Sep 17 00:00:00 2001 From: Ben Skeggs Date: Tue, 31 Jan 2012 09:16:59 +1000 Subject: drm/nouveau/disp: check that panel power gpio is enabled at init time Reported-by: Yuriy Khomchik Signed-off-by: Ben Skeggs --- drivers/gpu/drm/nouveau/nouveau_bios.h | 5 +++-- drivers/gpu/drm/nouveau/nouveau_display.c | 10 ++++++++++ 2 files changed, 13 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/gpu/drm/nouveau/nouveau_bios.h b/drivers/gpu/drm/nouveau/nouveau_bios.h index 1e382ad5a2b8..a37c31e358aa 100644 --- a/drivers/gpu/drm/nouveau/nouveau_bios.h +++ b/drivers/gpu/drm/nouveau/nouveau_bios.h @@ -54,9 +54,10 @@ struct bit_entry { int bit_table(struct drm_device *, u8 id, struct bit_entry *); enum dcb_gpio_tag { - DCB_GPIO_TVDAC0 = 0xc, + DCB_GPIO_PANEL_POWER = 0x01, + DCB_GPIO_TVDAC0 = 0x0c, DCB_GPIO_TVDAC1 = 0x2d, - DCB_GPIO_PWM_FAN = 0x9, + DCB_GPIO_PWM_FAN = 0x09, DCB_GPIO_FAN_SENSE = 0x3d, DCB_GPIO_UNUSED = 0xff }; diff --git a/drivers/gpu/drm/nouveau/nouveau_display.c b/drivers/gpu/drm/nouveau/nouveau_display.c index 3cb52bc52b21..795a9e3c990a 100644 --- a/drivers/gpu/drm/nouveau/nouveau_display.c +++ b/drivers/gpu/drm/nouveau/nouveau_display.c @@ -219,6 +219,16 @@ nouveau_display_init(struct drm_device *dev) if (ret) return ret; + /* power on internal panel if it's not already. the init tables of + * some vbios default this to off for some reason, causing the + * panel to not work after resume + */ + if (nouveau_gpio_func_get(dev, DCB_GPIO_PANEL_POWER) == 0) { + nouveau_gpio_func_set(dev, DCB_GPIO_PANEL_POWER, true); + msleep(300); + } + + /* enable polling for external displays */ drm_kms_helper_poll_enable(dev); /* enable hotplug interrupts */ -- cgit v1.2.3 From ce2e7895faba8fabaa917f52293126e5f4174fa9 Mon Sep 17 00:00:00 2001 From: Ben Skeggs Date: Wed, 1 Feb 2012 15:08:59 +1000 Subject: drm/nouveau/mxm: pretend to succeed, even if we can't shadow the MXM-SIS There's at least one known case where our shadowing code is buggy, and we fail init. Until we can be confident we're doing all this correctly, lets succeed and risk crazy bios tables rather than failing for perfectly valid configs too. Signed-off-by: Ben Skeggs --- drivers/gpu/drm/nouveau/nouveau_mxm.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'drivers') diff --git a/drivers/gpu/drm/nouveau/nouveau_mxm.c b/drivers/gpu/drm/nouveau/nouveau_mxm.c index 8bccddf4eff0..e5a64f0f4cb7 100644 --- a/drivers/gpu/drm/nouveau/nouveau_mxm.c +++ b/drivers/gpu/drm/nouveau/nouveau_mxm.c @@ -656,7 +656,16 @@ nouveau_mxm_init(struct drm_device *dev) if (mxm_shadow(dev, mxm[0])) { MXM_MSG(dev, "failed to locate valid SIS\n"); +#if 0 + /* we should, perhaps, fall back to some kind of limited + * mode here if the x86 vbios hasn't already done the + * work for us (so we prevent loading with completely + * whacked vbios tables). + */ return -EINVAL; +#else + return 0; +#endif } MXM_MSG(dev, "MXMS Version %d.%d\n", -- cgit v1.2.3 From 1eb8a619b43c1e99179ebadbc9c614ed37358f2d Mon Sep 17 00:00:00 2001 From: Ben Skeggs Date: Sat, 7 Jan 2012 16:48:52 +1000 Subject: drm/nouveau: fix typo on mxmdcb option Signed-off-by: Ben Skeggs --- drivers/gpu/drm/nouveau/nouveau_drv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.c b/drivers/gpu/drm/nouveau/nouveau_drv.c index e4a7cfe7898d..81d7962e7252 100644 --- a/drivers/gpu/drm/nouveau/nouveau_drv.c +++ b/drivers/gpu/drm/nouveau/nouveau_drv.c @@ -124,7 +124,7 @@ MODULE_PARM_DESC(ctxfw, "Use external HUB/GPC ucode (fermi)\n"); int nouveau_ctxfw; module_param_named(ctxfw, nouveau_ctxfw, int, 0400); -MODULE_PARM_DESC(ctxfw, "Santise DCB table according to MXM-SIS\n"); +MODULE_PARM_DESC(mxmdcb, "Santise DCB table according to MXM-SIS\n"); int nouveau_mxmdcb = 1; module_param_named(mxmdcb, nouveau_mxmdcb, int, 0400); -- cgit v1.2.3 From 525895ba388c949aa906f26e3ec5cb1ab041f56b Mon Sep 17 00:00:00 2001 From: Ben Skeggs Date: Tue, 10 Jan 2012 10:18:28 +1000 Subject: drm/nouveau/gem: fix fence_sync race / oops Due to a race it was possible for a fence to be destroyed while another thread was trying to synchronise with it. If this happened in the fallback non-semaphore path, it lead to the following oops due to fence->channel being NULL. BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] nouveau_fence_update+0xe/0xe0 [nouveau] *pde = a649c067 SMP Modules linked in: fuse nouveau(O) ttm(O) drm_kms_helper(O) drm(O) mxm_wmi video wmi netconsole configfs lockd bnep bluetooth rfkill ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack ip6table_filter ip6_tables snd_hda_codec_realtek snd_hda_intel snd_hda_cobinfmt_misc uinput ata_generic pata_acpi pata_aet2c_algo_bit i2c_core [last unloaded: wmi] Pid: 2255, comm: gnome-shell Tainted: G O 3.2.0-0.rc5.git0.1.fc17.i686 #1 System manufacturer System Product Name/M2A-VM EIP: 0060:[] EFLAGS: 00010296 CPU: 1 EIP is at nouveau_fence_update+0xe/0xe0 [nouveau] EAX: 00000000 EBX: ddfc6dd0 ECX: dd111580 EDX: 00000000 ESI: 00003e80 EDI: dd111580 EBP: dd121d00 ESP: dd121ce8 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 Process gnome-shell (pid: 2255, ti=dd120000 task=dd111580 task.ti=dd120000) Stack: 7dc86c76 00000000 00003e80 ddfc6dd0 00003e80 dd111580 dd121d0c fa96371f 00000000 dd121d3c fa963773 dd111580 01000246 000ec53d 00000000 ddfc6dd0 00001f40 00000000 ddfc6dd0 00000010 dc7df840 dd121d6c fa9639a0 00000000 Call Trace: [] __nouveau_fence_signalled+0x1f/0x30 [nouveau] [] __nouveau_fence_wait+0x43/0xd0 [nouveau] [] nouveau_fence_sync+0x1a0/0x1c0 [nouveau] [] validate_list+0x176/0x300 [nouveau] [] ? ttm_bo_mem_put+0x30/0x30 [ttm] [] nouveau_gem_ioctl_pushbuf+0x48a/0xfd0 [nouveau] [] ? die+0x31/0x80 [] drm_ioctl+0x388/0x490 [drm] [] ? die+0x31/0x80 [] ? nouveau_gem_ioctl_new+0x150/0x150 [nouveau] [] ? file_has_perm+0xcb/0xe0 [] ? drm_copy_field+0x80/0x80 [drm] [] do_vfs_ioctl+0x86/0x5b0 [] ? die+0x31/0x80 [] ? selinux_file_ioctl+0x62/0x130 [] ? fget_light+0x30/0x340 [] sys_ioctl+0x6f/0x80 [] syscall_call+0x7/0xb [] ? die+0x31/0x80 [] ? die+0x31/0x80 Signed-off-by: Ben Skeggs Cc: stable@vger.kernel.org --- drivers/gpu/drm/nouveau/nouveau_gem.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c index 5f0bc57fdaab..7ce3fde40743 100644 --- a/drivers/gpu/drm/nouveau/nouveau_gem.c +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c @@ -379,6 +379,25 @@ retry: return 0; } +static int +validate_sync(struct nouveau_channel *chan, struct nouveau_bo *nvbo) +{ + struct nouveau_fence *fence = NULL; + int ret = 0; + + spin_lock(&nvbo->bo.bdev->fence_lock); + if (nvbo->bo.sync_obj) + fence = nouveau_fence_ref(nvbo->bo.sync_obj); + spin_unlock(&nvbo->bo.bdev->fence_lock); + + if (fence) { + ret = nouveau_fence_sync(fence, chan); + nouveau_fence_unref(&fence); + } + + return ret; +} + static int validate_list(struct nouveau_channel *chan, struct list_head *list, struct drm_nouveau_gem_pushbuf_bo *pbbo, uint64_t user_pbbo_ptr) @@ -393,7 +412,7 @@ validate_list(struct nouveau_channel *chan, struct list_head *list, list_for_each_entry(nvbo, list, entry) { struct drm_nouveau_gem_pushbuf_bo *b = &pbbo[nvbo->pbbo_index]; - ret = nouveau_fence_sync(nvbo->bo.sync_obj, chan); + ret = validate_sync(chan, nvbo); if (unlikely(ret)) { NV_ERROR(dev, "fail pre-validate sync\n"); return ret; @@ -416,7 +435,7 @@ validate_list(struct nouveau_channel *chan, struct list_head *list, return ret; } - ret = nouveau_fence_sync(nvbo->bo.sync_obj, chan); + ret = validate_sync(chan, nvbo); if (unlikely(ret)) { NV_ERROR(dev, "fail post-validate sync\n"); return ret; -- cgit v1.2.3 From a9d993882008a1ae2c953064f0c2ca7e604b1333 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Wed, 4 Jan 2012 10:20:47 +0300 Subject: drm/nv50/pm: signedness bug in nv50_pm_clocks_pre() calc_mclk() returns zero on success and negative on failure but clk is a u32. v2: Martin Peres: - clk should be an int, not a u32 Signed-off-by: Martin Peres Signed-off-by: Dan Carpenter Signed-off-by: Ben Skeggs --- drivers/gpu/drm/nouveau/nv50_pm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/gpu/drm/nouveau/nv50_pm.c b/drivers/gpu/drm/nouveau/nv50_pm.c index 03937212e9d8..ec5481dfcd82 100644 --- a/drivers/gpu/drm/nouveau/nv50_pm.c +++ b/drivers/gpu/drm/nouveau/nv50_pm.c @@ -495,9 +495,9 @@ nv50_pm_clocks_pre(struct drm_device *dev, struct nouveau_pm_level *perflvl) struct drm_nouveau_private *dev_priv = dev->dev_private; struct nv50_pm_state *info; struct pll_lims pll; - int ret = -EINVAL; + int clk, ret = -EINVAL; int N, M, P1, P2; - u32 clk, out; + u32 out; if (dev_priv->chipset == 0xaa || dev_priv->chipset == 0xac) -- cgit v1.2.3 From 86698c20f71d488b32c49ed4687fb3cf8a88a5ca Mon Sep 17 00:00:00 2001 From: Seth Forshee Date: Tue, 31 Jan 2012 19:06:25 -0600 Subject: drm/radeon/kms: disable output polling when suspended Polling the outputs when the device is suspended can result in erroneous status updates. Disable output polling during suspend to prevent this from happening. Signed-off-by: Seth Forshee Reviewed-by: Alex Deucher Cc: stable@vger.kernel.org Signed-off-by: Dave Airlie --- drivers/gpu/drm/radeon/radeon_device.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers') diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c index cec51a5b69dd..49f7cb7e226b 100644 --- a/drivers/gpu/drm/radeon/radeon_device.c +++ b/drivers/gpu/drm/radeon/radeon_device.c @@ -883,6 +883,8 @@ int radeon_suspend_kms(struct drm_device *dev, pm_message_t state) if (dev->switch_power_state == DRM_SWITCH_POWER_OFF) return 0; + drm_kms_helper_poll_disable(dev); + /* turn off display hw */ list_for_each_entry(connector, &dev->mode_config.connector_list, head) { drm_helper_connector_dpms(connector, DRM_MODE_DPMS_OFF); @@ -972,6 +974,8 @@ int radeon_resume_kms(struct drm_device *dev) list_for_each_entry(connector, &dev->mode_config.connector_list, head) { drm_helper_connector_dpms(connector, DRM_MODE_DPMS_ON); } + + drm_kms_helper_poll_enable(dev); return 0; } -- cgit v1.2.3 From 1b61925061660009f5b8047f93c5297e04541273 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Michel=20D=C3=A4nzer?= Date: Wed, 1 Feb 2012 12:09:55 +0100 Subject: drm/radeon: Set DESKTOP_HEIGHT register to the framebuffer (not mode) height. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The value of this register is transferred to the V_COUNTER register at the beginning of vertical blank. V_COUNTER is the reference for VLINE waits and goes from VIEWPORT_Y_START to VIEWPORT_Y_START+VIEWPORT_HEIGHT during scanout, so if VIEWPORT_Y_START is not 0, V_COUNTER actually went backwards at the beginning of vertical blank, and VLINE waits excluding the whole scanout area could never finish (possibly only if VIEWPORT_Y_START is larger than the length of vertical blank in scanlines). Setting DESKTOP_HEIGHT to the framebuffer height should prevent this for any kind of VLINE wait. Fixes https://bugs.freedesktop.org/show_bug.cgi?id=45329 . CC: stable@vger.kernel.org Signed-off-by: Michel Dänzer Reviewed-by: Alex Deucher Signed-off-by: Dave Airlie --- drivers/gpu/drm/radeon/atombios_crtc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c index 891935271d34..742f17f009a9 100644 --- a/drivers/gpu/drm/radeon/atombios_crtc.c +++ b/drivers/gpu/drm/radeon/atombios_crtc.c @@ -1184,7 +1184,7 @@ static int dce4_crtc_do_set_base(struct drm_crtc *crtc, WREG32(EVERGREEN_GRPH_ENABLE + radeon_crtc->crtc_offset, 1); WREG32(EVERGREEN_DESKTOP_HEIGHT + radeon_crtc->crtc_offset, - crtc->mode.vdisplay); + target_fb->height); x &= ~3; y &= ~1; WREG32(EVERGREEN_VIEWPORT_START + radeon_crtc->crtc_offset, @@ -1353,7 +1353,7 @@ static int avivo_crtc_do_set_base(struct drm_crtc *crtc, WREG32(AVIVO_D1GRPH_ENABLE + radeon_crtc->crtc_offset, 1); WREG32(AVIVO_D1MODE_DESKTOP_HEIGHT + radeon_crtc->crtc_offset, - crtc->mode.vdisplay); + target_fb->height); x &= ~3; y &= ~1; WREG32(AVIVO_D1MODE_VIEWPORT_START + radeon_crtc->crtc_offset, -- cgit v1.2.3 From 3f7e363249ad5f4070025f6c09fd264f93f24eab Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Tue, 31 Jan 2012 09:55:21 +0100 Subject: drm/radeon/kms: Fix device tree linkage of DP i2c buses too Properly set the parent device of DP i2c buses before registering them too. Signed-off-by: Jean Delvare Reviewed-by: Alex Deucher Signed-off-by: Dave Airlie --- drivers/gpu/drm/radeon/radeon_i2c.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers') diff --git a/drivers/gpu/drm/radeon/radeon_i2c.c b/drivers/gpu/drm/radeon/radeon_i2c.c index e2a393ff0c44..98a8ad680109 100644 --- a/drivers/gpu/drm/radeon/radeon_i2c.c +++ b/drivers/gpu/drm/radeon/radeon_i2c.c @@ -958,6 +958,7 @@ struct radeon_i2c_chan *radeon_i2c_create_dp(struct drm_device *dev, i2c->rec = *rec; i2c->adapter.owner = THIS_MODULE; i2c->adapter.class = I2C_CLASS_DDC; + i2c->adapter.dev.parent = &dev->pdev->dev; i2c->dev = dev; snprintf(i2c->adapter.name, sizeof(i2c->adapter.name), "Radeon aux bus %s", name); -- cgit v1.2.3 From de47a9cd62771e3e78954d855d2304fbad4c5a44 Mon Sep 17 00:00:00 2001 From: Dave Airlie Date: Thu, 2 Feb 2012 15:25:16 +0000 Subject: drm/radeon: fix use after free in ATRM bios reading code. Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=45503 Reported-and-Debugged-by: mlambda@gmail.com Signed-off-by: Dave Airlie --- drivers/gpu/drm/radeon/radeon_atpx_handler.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/gpu/drm/radeon/radeon_atpx_handler.c b/drivers/gpu/drm/radeon/radeon_atpx_handler.c index 13ac63ba6075..98724fcb0088 100644 --- a/drivers/gpu/drm/radeon/radeon_atpx_handler.c +++ b/drivers/gpu/drm/radeon/radeon_atpx_handler.c @@ -59,8 +59,9 @@ static int radeon_atrm_call(acpi_handle atrm_handle, uint8_t *bios, obj = (union acpi_object *)buffer.pointer; memcpy(bios+offset, obj->buffer.pointer, obj->buffer.length); + len = obj->buffer.length; kfree(buffer.pointer); - return obj->buffer.length; + return len; } bool radeon_atrm_supported(struct pci_dev *pdev) -- cgit v1.2.3 From 304a48400d9718f74ec35ae46f30868a5f4c4516 Mon Sep 17 00:00:00 2001 From: Alex Deucher Date: Thu, 2 Feb 2012 10:18:00 -0500 Subject: drm/radeon/kms: fix TRAVIS panel setup Different versions of the DP to LVDS bridge chip need different panel mode settings depending on the chip version used. Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=41569 Signed-off-by: Alex Deucher Cc: stable@vger.kernel.org Signed-off-by: Dave Airlie --- drivers/gpu/drm/radeon/atombios_dp.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) (limited to 'drivers') diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c index a71557ce01dc..552b436451fd 100644 --- a/drivers/gpu/drm/radeon/atombios_dp.c +++ b/drivers/gpu/drm/radeon/atombios_dp.c @@ -564,9 +564,21 @@ int radeon_dp_get_panel_mode(struct drm_encoder *encoder, ENCODER_OBJECT_ID_NUTMEG) panel_mode = DP_PANEL_MODE_INTERNAL_DP1_MODE; else if (radeon_connector_encoder_get_dp_bridge_encoder_id(connector) == - ENCODER_OBJECT_ID_TRAVIS) - panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE; - else if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) { + ENCODER_OBJECT_ID_TRAVIS) { + u8 id[6]; + int i; + for (i = 0; i < 6; i++) + id[i] = radeon_read_dpcd_reg(radeon_connector, 0x503 + i); + if (id[0] == 0x73 && + id[1] == 0x69 && + id[2] == 0x76 && + id[3] == 0x61 && + id[4] == 0x72 && + id[5] == 0x54) + panel_mode = DP_PANEL_MODE_INTERNAL_DP1_MODE; + else + panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE; + } else if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) { u8 tmp = radeon_read_dpcd_reg(radeon_connector, DP_EDP_CONFIGURATION_CAP); if (tmp & 1) panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE; -- cgit v1.2.3 From 52b53a0bf8026a322cfa6cfec6a10dd31fef8752 Mon Sep 17 00:00:00 2001 From: Ilija Hadzic Date: Thu, 2 Feb 2012 10:26:24 -0500 Subject: drm/radeon/kms/blit: fix blit copy for very large buffers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Evergreen and NI blit copy was broken if the buffer maps to a rectangle whose one dimension is 16384 (max dimension allowed by these chips). In the mainline kernel, the problem is exposed only when buffers are very large (1G), but it's still a problem. The problem could be exposed for smaller buffers if anyone modifies the algorithm for rectangle construction in r600_blit_create_rect() (the reason why someone would modify that algorithm is to tune the performance of buffer moves). The root cause was in i2f() function which only operated on range between 0 and 16383. Fix this by extending the range of i2f() function to 0 to 32767. While at it improve the function so that the range can be easily extended in the future (if it becomes necessary), cleanup lines over 80 characters, and replace in-line comments with one strategic comment that explains the crux of the function. Credits to michel@daenzer.net for pointing out the root cause of the bug. v2: Fix I2F_MAX_INPUT constant definition goof and warn only once if input argument is out of range. Edit the comment a little bit to avoid some linguistic confusion and make it look better in general. Signed-off-by: Ilija Hadzic Reviewed-by: Alex Deucher Reviewed-by: Michel Dänzer Signed-off-by: Dave Airlie --- drivers/gpu/drm/radeon/r600_blit_kms.c | 35 ++++++++++++++++++++++++---------- 1 file changed, 25 insertions(+), 10 deletions(-) (limited to 'drivers') diff --git a/drivers/gpu/drm/radeon/r600_blit_kms.c b/drivers/gpu/drm/radeon/r600_blit_kms.c index d996f4381130..accc032c103f 100644 --- a/drivers/gpu/drm/radeon/r600_blit_kms.c +++ b/drivers/gpu/drm/radeon/r600_blit_kms.c @@ -468,27 +468,42 @@ set_default_state(struct radeon_device *rdev) radeon_ring_write(ring, sq_stack_resource_mgmt_2); } +#define I2F_MAX_BITS 15 +#define I2F_MAX_INPUT ((1 << I2F_MAX_BITS) - 1) +#define I2F_SHIFT (24 - I2F_MAX_BITS) + +/* + * Converts unsigned integer into 32-bit IEEE floating point representation. + * Conversion is not universal and only works for the range from 0 + * to 2^I2F_MAX_BITS-1. Currently we only use it with inputs between + * 0 and 16384 (inclusive), so I2F_MAX_BITS=15 is enough. If necessary, + * I2F_MAX_BITS can be increased, but that will add to the loop iterations + * and slow us down. Conversion is done by shifting the input and counting + * down until the first 1 reaches bit position 23. The resulting counter + * and the shifted input are, respectively, the exponent and the fraction. + * The sign is always zero. + */ static uint32_t i2f(uint32_t input) { u32 result, i, exponent, fraction; - if ((input & 0x3fff) == 0) - result = 0; /* 0 is a special case */ + WARN_ON_ONCE(input > I2F_MAX_INPUT); + + if ((input & I2F_MAX_INPUT) == 0) + result = 0; else { - exponent = 140; /* exponent biased by 127; */ - fraction = (input & 0x3fff) << 10; /* cheat and only - handle numbers below 2^^15 */ - for (i = 0; i < 14; i++) { + exponent = 126 + I2F_MAX_BITS; + fraction = (input & I2F_MAX_INPUT) << I2F_SHIFT; + + for (i = 0; i < I2F_MAX_BITS; i++) { if (fraction & 0x800000) break; else { - fraction = fraction << 1; /* keep - shifting left until top bit = 1 */ + fraction = fraction << 1; exponent = exponent - 1; } } - result = exponent << 23 | (fraction & 0x7fffff); /* mask - off top bit; assumed 1 */ + result = exponent << 23 | (fraction & 0x7fffff); } return result; } -- cgit v1.2.3